Nanodiamonds have emerged as promising agents for drug delivery and imaging due to their unique surface properties. Nanodiamond-anthracycline compounds have mediated major improvements to drug delivery efficacy and safety. Most recently, NDX, a nanodiamond-doxorubicin agent, markedly enhanced the pre-clinical treatment efficacy of multiple drug-resistant tumor models with no apparent myelosuppression, demonstrating potent drug binding and the absence of early drug release [1]. Nanodiamonds bound to gadolinium have also resulted in contrast agents that are 12 times more efficient than clinical standards with among the highest ever reported per-gadolinium relaxivity values. This lecture will highlight recent advancements in the use of nanodiamond-anthracycline complexes to address hard to treat cancers. In addition, diamond-based multimodal imaging/therapy approaches will be explored as potential clinically-relevant modalities [2]. The combination of these pre-clinical advancements in diamond-based nanomedicine and nanodiamond surface properties serves as a foundation for a promising translational roadmap which will also be discussed [3]. Furthermore, this work will highlight our recent progress towards developing improved nanodiamond drug delivery devices that can modulate the specificity of treatment to attenuate systemic toxicity.
References
[1] EK Chow, et al. Science Translational Medicine, 73ra21, 2011.
[2] LK Moore, et al. Advanced Materials, 25, 3532-3541, 2013.
[3] V Mochalin, et al. Nature Nanotechnology, 7, 2012.

Ultra Nano Crystalline Diamond (UNCD) films grown by microwave plasma chemical vapor deposition (MPCVD) exhibit a unique set of multifunctionalities and properties (Young&’s Modulus and hardness equivalent to single crystal diamond, the lowest coefficient of friction among known thin films, electrical conductivity with nitrogen incorporated in grain boundaries or boron substituting C atoms in the diamond lattice, and outstanding biocompatibility) for potential applications to mechanical, electronic, chemical and bio-medical devices, respectively.
One of the important issues related to the synthesis of UNCD films for application to the development of a new generation of multifunctional devices is achieving thickness and nanostructure uniformity over large area substrates (ge; 4 inch in diameter) with 3~5 nm grain size. Here, we report an advanced process of hot filament chemical vapor deposition (HFCVD) system to show the synthesis of UNCD films with thickness, nanostructure and chemical bonding uniformity in the range of ± 3-5 %, verified with HR-TEM, Raman spectroscopy, and XPS. We also investigated the surface morphology using SEM and AFM, which revealed extremely smooth surface (~ 3-5 nm rms). The role of Ar, CH4 and H2 relative proportions, in the gas mixture used to grow HFCVD UNCD films, will be discussed in relation to their impact to get the nanoscale grains characteristic of UNCD films produced by the MPCVD method.
This development of an HFCVD process to produce UNCD films with excellent uniformity on large area substrates has implications to accelerate the practical applications of the UNCD films for the development of a new generation of high-tech devices/systems and bio-medical devices.
To whom correspondence should be addressed. E-mail: [email protected]

Multi-shell fullerenes, known as carbon nano-onions (CNOs), were discovered in 1992, are structured by concentric shells of carbon atoms.1 They display several unique properties, such as a large surface area to volume ratio, a low density and a graphitic multilayer morphology. Analogous to carbon nanotubes, CNOs display poor solubility in both aqueous and organic solvents. We have recently reported a versatile approach for the functionalisation of CNOs, which involves the facile introduction of a number of simple functionalities onto their surface by treatment with in-situ generated diazonium compounds. We were also able to attach more complex fluorescent molecules to CNOs using “click” chemistry.2 Recently we have shown that chemical functionalization of the CNOs dramatically enhance their solubility and attenuate their inflammatory properties.3
In this work we report a robust and versatile synthetic multi-functionalisation strategy for the introduction of two different functionalities onto the surface of the CNO. We coupled the nano-onion to a receptor targeting unit and an imaging unit. The characterisation of the surface chemistry of the di-functionalised CNOs was carried out using X-ray Photoemission Spectroscopy (XPS) and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS), whilst the morphology was assessed by means of AFM and TEM.
1. Urgate D. Nature 1992, 359, 707-709.
2. Flavin K, Chaur N, Echegoyen L, Giordani S. Org Lett 2010, 12, 840-843.
3. Yang M., Flavin K., Kopf I., Radics G., Hearnden .H.A., McManus G. J., Moran B., Villalta-Cerdas A., Echegoyen L., Giordani S., Lavelle E.C. Small 2013, DOI: 10.1002/smll.201300481.

Diamond nanoparticles, also known as nanodiamonds (NDs), have been gaining popularity as molecular delivery vehicles over the last decade. The uniquely faceted, carbon nanoparticles possess a number of beneficial properties that have been harnessed for applications in biomedical imaging and drug delivery. NDs promote internalization and retention of their cargo while limiting non-specific uptake during circulation, thereby improving therapeutic efficacy while reducing the toxicity of a number of chemotherapeutic drugs (1,2). At the same time, the water shell formed around the particles is capable of mediating a more than 10-fold enhancement in per gadolinium relaxivity, which can be harnessed for magnetic resonance imaging (3). Although research demonstrates NDs are highly effective vehicles, one of the main challenges with all types of nanoparticles is biocompatibility. Preliminary studies of NDs indicate that the particles are non-toxic, however the studies have only evaluated a fraction of ND subtypes. Here we present an in depth analysis of the cellular response to multiple subtypes of NDs, including pristine, amine functionalized, fluorescent and daunorubicin-loaded NDs. Furthermore, we present the most comprehensive analysis of in vivo tolerance of nanodiamonds to date. We find that NDs, regardless of subtype, are non-toxic to multiple cell types. In addition, daunorubicin is less toxic when delivered to non-resistant cell lines by NDs. Finally, we find that systemic administration of multiple doses of NDs to rats has little impact on serum chemistry, hematological or urine indicators of organ function. Combined these results indicate that NDs are highly biocompatible and will serve as the foundation for future clinical translation of diamond-based imaging or therapeutic agents.
1. Chow, E. K. et al. Nanodiamond therapeutic delivery agents mediate enhanced chemoresistant tumor treatment. Sci. Transl. Med. 3, 73ra21 (2011).
2. Moore, L., Chow, E. K.-H., Osawa, E., Bishop, J. M. & Ho, D. Diamond-Lipid Hybrids Enhance Chemotherapeutic Tolerance and Mediate Tumor Regression. Adv. Mater. 1-10 (2013). doi:10.1002/adma.201300343
3. Manus, L. M. et al. Gd(III)-nanodiamond conjugates for MRI contrast enhancement. Nano Lett. 10, 484-489 (2010).

There is now clear evidence that many cancers contain subpopulations of cells that have enhanced tumor-initiating properties. These cells, termed CSCs, are thought to be responsible for tumorigenesis, metastasis and recurrence following initial treatment. These cells also often have intrinsic chemoresistant properties. Thus, conventional chemotherapy does not appear to be useful in fully eradicating these CSCs and alternative methods of therapy are needed to target and eliminate these tumor-initiating cells. We have previously demonstrated that CSCs express specific cell surface markers and mechanisms of chemoresistance based on the initiating oncogenes.
Nanodiamonds (NDs) are a versatile drug delivery platform that can be functionalized with a broad array of molecules, including small molecules, proteins and genetic material. The uniformity, stability and size (~4nm) of NDs lend themselves to clinical use as biocompatible drug delivery and imaging reagents. As such, we evaluated the use of NDs in targeted drug-delivery and imaging in multiple in vivo cancer models, including liver and breast cancer. We have now demonstrated over a wide range of chemotherapeutics, that NDs are a potent platform for developing novel drug formulations that can overcome the most common mechanisms of chemoresistance. This includes the specific mechanisms that mediate chemoresistance in CSCs. Complexing chemotherapeutics with nanodiamonds resulted in enhanced drug efficacy while lowering the toxic effects normally seen in standard chemotherapy treatment. Furthermore, addition of a targeting component greatly enhanced tumor treatment efficacy by ND-drug complexes with regression seen in some cases. Enhanced efficacy was seen while ND-drug association maintained lower systemic toxicity. In addition to enhancing drug-delivery, unique chemical properties in NDs make them an ideal platform for enhanced cancer imaging, particular near infrared and magnetic resonance based imaging. This work provides the preclinical base for the application of nanodiamonds in cancer therapy and diagnostics. As cancer therapy moves towards a more individualized approach where genomic-based diagnosis is combined with targeted patient-specific treatment, nanodiamonds provide a platform from which multiple targeted and therapeutic options can be derived to treat the individual more efficiently based on their unique genomic alterations.

Celecoxib (Cxb) is currently the only COX-2 (cyclooxygenase) inhibitor available on the market because other similar drugs have been withdrawn due to serious side effects. These side effects include myelosuppression, hepatotoxicity and cardiovascular complications. Hence, an oral cancer device must allow the sustained release of drug at therapeutically relevant level at target sites. Burst release often leads to drug loss into systemic circulation and subsequent toxicity.
Oral mucoadhesive devices are ideal for localized drug delivery to oral cancer lesions. This delivery method bypasses the hepatic first-pass effect and gastrointestinal degradation which greatly decrease drug concentrations. Administering the device is simple and non-invasive. While the needle injection method can bypass the first-pass effect, the procedure is traumatic for patients and not practical for frequent administration. This advantageous mucoadhesive system can be combined with nanoparticle technology to generate an effective drug delivery device. Recently, nanodiamonds (NDs) have been presented as a promising platform for drug delivery and numerous other biomedical applications. NDs are capable of sustaining drug release, targeting drugs to tumor sites after systemic circulation, and overcoming drug efflux mechanisms of cancer cells. NDs also appear to be well tolerated.
We present a multi-modular ND construct which will be gradually released from a mucoadhesive patch containing alginate hydrogel. The construct will be designed to stabilize hydrophobic Cxb, penetrate the oral mucosa, and release Cxb inside oral cancer cells in a targeted fashion. Targeting enhances specificity of activity, which will thus improve efficacy and safety. In addition, we will evaluate the effectiveness of NDs in overcoming chemoresistance by using Cxb-resistant cell lines. Release profiles of NDs from the alginate hydrogel and the mucosal penetrating ability of the NDs will also be examined.

The utilization of nanodiamonds in the field of drug delivery possesses many advantages. They&’ve been shown to be chemically inert, biocompatible, and their high surface area allows for the absorption of drugs, such as chemo, to their surface. Also, when carboxylated, nanodiamond-based systems can be functionalized with various proteins, antibodies, and other biomolecules which can give them the ability to target, image and deliver chemo to specific sites in the body, such as cancer cells, thus reducing toxicity at healthy sites and increasing the drug dosage at malignant sites. This fact, along with their ability to transfect the cell membrane has been shown to make chemo more effective when combined with the nanodiamonds as oppose to using the drug alone. Our primary goal in this study is to develop a composite drug delivery system composed of electrospun PLGA [poly(lactic-co-glycolic acid)] polymer nanofibers and detonation nanodiamonds that give a controlled and sustained release of doxorubicin as a function of polymer degradation time and weight percent nanodiamond loading. This project will also consist of the synthesis and characterization of detonation nanodiamonds with cyclo arginine-glycine-aspartic acid (RGD) peptide, which will be used to selectively target the alphaVbeta3 integrin that is over-expressed in tumor angiogenesis and certain types of cancers. This research has the potential to impact the way chemotherapy drugs are administered and to enhance the overall quality of localized cancer treatment.

Nanodiamond, a member of the nanocarbon family, exhibits the excellent mechanical, thermal and electrical properties of diamond at nanoscale. Meantime, nanodiamond has many unique features, such as small size, high specific area and optical fluorescence. Recently years, researchers give more attentions on the studies of structure&’s engineering and potential application&’s developing [1-3]. Nanodiamond is formed by sp3 carbon with very rich surface structures, especially sp2 carbon and various surface chemical groups, such as C=O, COOH, and OH. In our study, a facile method of strong oxidation has been used to remove sp2 carbon and established a homogeneous initial surface termination. Subsequently, the oxidized samples were used as the starting material to react with the coupling agents for improving filler dispersion in the polymer matrix and creating new multifunctional nanocomposites with high performances. In order to verify the effect of modification, various tools including FTIR, Raman and XANES, were employed to characterize the prepared nanodiamond samples. These results may provide some useful insights for understanding the structure of modified nanodiamond as well as its further applications.

Celecoxib (Cxb) is a hydrophobic drug with the potential to treat oral cancers. However, conventional administration of Cxb via capsule-based ingestion is inefficient due to the hepatic first-pass effect and gastrointestinal degradation, resulting in low drug concentration at oral cancer lesions. Therefore, higher drug dosages are needed, and this can cause systemic toxicity. Needle injection at tumor sites may bypass the first-pass effect, but the procedure is traumatic for patients and not practical for frequent administration.
To circumvent these issues, sustained and localized delivery of Cxb to oral cancer lesions is required. However, hydrophobic drugs like Cxb are not only unstable in the aqueous oral cavity but are also incapable of penetrating the oral mucosa. To facilitate the sustained and localized release of Cxb into oral cancer lesions, we propose a mucoadhesive buccal hydrogel patch embedded with nanodiamond-Cxb complexes. Nanodiamonds (NDs) are carbon nanoparticles that serve as effective drug carriers due to their surface functionality, biocompatibility, and drug sequestration capability. Successful in vivo studies performed with doxorubicin-loaded NDs and mice mammary tumors not only demonstrated the viability of NDs as a drug delivery platform but also showed that drug-loaded NDs can avoid drug resistance mechanisms associated with chemoresistant cancer cells. Thus, we believe that our ND-Cxb complex can overcome Cxb-resistant oral cancer cells.
Our NDs will be functionalized to enhance mucosal penetration. In addition, a final layer of targeting ligands will be used to enhance the specificity of treatment. We are also currently conducting studies involving the loading of Cxb into the multifunctional ND construct and the subsequent release of Cxb from this construct, which will be highlighted.

Nanodiamond particles (ND) have great potential in various adsorption applications, including drug delivery, chromatography, protein purification, and toxin sorption [1]. Although the potential of ND in each of these applications as been demonstrated, the general mechanisms of adsorption on NDs with different purity and surface chemistry are still less understood. In part this is due to our inability to control the purity and surface chemistry of nanodiamond in the past. Now, having well established nanodiamond purification and surface modification techniques, we are in a much better position to study the mechanisms of adsorption on clean nanodiamonds with different surface chemistry [2]. As a part of this study, in this presentation we will report our recent data on adsorption of different molecules on nanodiamonds with different and well controlled surface chemistry. These results will be important for the development of future applications for nanodiamonds in chromatography, electrophoresis, drug delivery, isolation of biomolecules, and others, where adsorption plays a crucial role.
1. Mochalin, V. N.; Shenderova, O.; Ho, D.; Gogotsi, Y., The properties and applications of nanodiamonds. Nature Nanotechnology 2012, 7, 11-23.
2. Mochalin, V. N.; Pentecost, A.; Li, X.-M.; Neitzel, I.; Nelson, M.; Wei, C.; He, T.; Guo, F.; Gogotsi, Y., Adsorption of Drugs on Nanodiamond: Toward Development of a Drug Delivery Platform. Molecular Pharmaceutics 2013, 10, 3728-3735.

Avascular necrosis is cell death of joints, jaws, hips as a result of inflammation, trauma, etc. and it often leads to bone implantations. However, insufficient vascularization around bone implants hinders bone implants performances and results in their rather short lifetime in tissue engineering. In order to initiate and promote the angiogenesis surrounding bone implants&’ surfaces and enhance biocompatibility, Federal Drug Administration (FDA) approved seven factors (Bone Morphogenetic Protein 2, Vascular Endothelial Growth Factor, Angiopoietin, Fibronectin, Arginylglycylaspartic acid,Chitosan and Heparin) are introduced for implants surface design and tissue engineering applications.
Diamond possesses incomparable chemical and biological properties, such as good chemical stabilities and biocompatibility, which makes it to be a good candidate for implants surface design. Hence, diamond can serve as delivery device for various growth factors with versatile physiological functions. Thus, the surface chemical reactivities and properties can easily be tuned by changing surface planes and terminations, so the functionalization of different growth factors can be manipulated in accordance with specific clinical situations.
The present work has focused on the surface design of medical implants for patients by investigating interactions between biomolecules and implants materials surfaces. Theoretical calculations have been performed with the purpose of predicting various biomolecules behaviors towards different materials surfaces planes and terminations. Calculations results show that for physisorption, adhesion energies of biomolecules are in proportion with their molecular weights. Concerning surface planes, diamond (111) surface plane displays higher affinity for biomolecules than diamond (100) surface. Specifically, preferences of different biomolecules towards different terminations may vary with their refined structures. The calculations results reveal the possibility of explaining experimental findings and tailor-made bio-implants surfaces for target environments and patients&’ needs.

Here, we present theoretical and experimental evidences for the feasibility of a fusion reaction of diamondoid derivatives with relatively reactive functional groups, diamantane-4,9-dicarboxylic acidto 1D diamond nanowires inside CNTs. The bisapical diamondoid diacid is more reactive than the pristine diamondoid, requiring milder reaction conditions. Unlike in 3D space, the diamantane dicarboxylic acid molecules are pulled inside a CNT by an effective “capillary force” that originates in the stabilization of the molecule inside the surrounding nanotube. This "capillary" force, in turn, compresses the enclosed molecular array of axially and aligns the molecules favorably. In this special surrounding environment, it may react in an unusual way to create an extended diamondoid cage during a mechanistically complex polymerization process. Hence, the fusion of diamantane-4,9-dicarboxylic acidto under the confinement of CNTs may be a promising choice to yield diamond nanowires.

Nanodiamond powder produced by detonation synthesis is the most promising nanofiller for composites [1]. It is made of diamond particles of ~5 nm in diameter, combining fully accessible surface with a rich and tailorable surface chemistry. Nanodiamond has unique optical, electrical, thermal, and mechanical properties, and is biocompatible and non-toxic. In order to fully benefit from the potential of nanodiamond in nanocomposites, several important issues must be addressed, such as uniformity of nanodiamond dispersion in the matrix, nanodiamond-matrix interface, and the properties of the polymer interphase formed in the vicinity of nanoparticles. These issues can be addressed by different purification, dispersion, and surface modification strategies. Covalent linking of hydrophobic molecules [2], improves dispersions of nanodiamond in hydrophobic polymers. Reactions of nanodiamond functional groups with the polymer matrix can be used to design a nanofiller-matrix interface and produce a significant volume of interphase in the composite [3]. The interphase formation depends on how nanodiamond changes the structure of polymer in the vicinity of the nanoparticle [4]. Incorporation of nanodiamond into polymers may improve their mechanical properties, thermal conductivity, UV-absorption, and other properties in many practical applications.
1. Mochalin, V. N.; Shenderova, O.; Ho, D.; Gogotsi, Y., The properties and applications of nanodiamonds. Nature Nanotechnology 2012, 7, 11-23.
2. Mochalin, V. N.; Gogotsi, Y., Wet Chemistry Route to Hydrophobic Blue Fluorescent Nanodiamond. Journal of the American Chemical Society 2009, 131, 4594-4595.
3. Mochalin, V. N.; Neitzel, I.; Etzold, B. J. M.; Peterson, A.; Palmese, G.; Gogotsi, Y., Covalent Incorporation of Aminated Nanodiamond into an Epoxy Polymer Network. ACS Nano 2011, 5, 7494-7502.
4. Guo, S.; Solares, S. D.; Mochalin, V.; Neitzel, I.; Gogotsi, Y.; Kalinin, S. V.; Jesse, S., Multifrequency imaging in the intermittent contact mode of atomic force microscopy: beyond phase imaging. Small 2012, 8, 1264-9.

The extraordinary physical properties of diamond, such as their catalytic activity, VIS/NIR optical transparency, large dielectric breakdown field, radiation hardness, p-type superconductivity, and chemical inertness make it a prime candidate for future high-performance optoelectronic devices. Consequently, diamond materials have received a substantial use in several applications such as catalysts for nitrogen reduction, optically-addressable qubits for quantum computing, long-term visible and near-infrared (NIR) in vitro cell labeling, and electrochemical double-layer capacitors. However, there are currently no well-established methods for synthesizing macroscopic (i.e., cubic-centimeter-scale) porous diamond materials. Furthermore, the performance of nanodiamonds in many applications is limited by the ability to achieve precise control over their production/processing and their ultimate atomistic microstructure. Here, we show fundamental control in nanodiamond synthesis and processing that includes the development of sol-gel assembly methods for the production of porous diamond from commercially-available detonation nanodiamond materials. Nanodiamond aerogels (NDAGs) with densities of <10mg/mL and surface areas > 400 m2/g will be discussed with characteristic volumes on the scale of cubic-centimeters. Sol-gel processing conditions also are identified that lead to rapid gelation rates, typically with time scales between 10 minutes and single-digit hours.

Porous graphitised carbon monoliths embedded with nanodiamonds (CMND) are presented in this work. Nanodiamond (ND) (sp3 carbon) has a variety of favourable properties including an interesting and tuneable surface chemistry, mechanical and thermal stability, and conductivity. CMND was prepared using a hard templating method. Bare 5 mu;m silica particles and detonation nanodiamonds (5-15 nm diameter) were added to the co-polymerisation mixture containing a resorcinol/iron(III) complex. Polymerisation of this mixture was followed by carbonisation at either 900 or 1250 °C under nitrogen. Removal of the silica template and catalyst was achieved by hydrofluoric acid etching. A blank carbon monolith (CM blank) was also prepared using bare silica templates for comparative purposes [1].
BET surface area measurements showed CMND to have a higher specific surface area than CM blank (400 m2/g and 349 m2/g respectively, with carbonisation at 900 °C). HRTEM and FESEM characterisation of CMND revealed a variety of interesting carbon nanostructures to be present in the monolith following carbonisation at 1250 °C. Apparent onion-like carbon (OLC), carbon nano-rods up to several mu;m in length and graphene sheets were observed. OLC clusters can be produced by a temperature-induced transformation of ND. The temperature of carbonisation was critical in the formation of these carbon nano-structures, as were the localised heating effects resulting from the thermal conductivity of ND. Carbon nano-structures have high surface areas and a high sorption capacity making them suitable for a variety of prospective applications. Porous graphitic carbons are also receiving significant research interest due to their high surface areas and bimodal pore structure which make them ideal for use in a variety of applications including energy storage, as electrode materials or as adsorbents in solid phase extraction.
1. He, X., Zhou, L., Nesterenko, E.P., Nesterenko, P.N., Paull, B., Omamogho, J.O., Glennon J.D., Luong, J.H.T. Anal. Chem. 2012, 84, 2531-2537.

Nanodiamonds have been detected in outer space (meteorites, interstellar dust), and synthetically produced by high pressure/high temperature (HPHT) conversion of graphite powder, detonation of carbon-containing explosives, and chemical vapor deposition (CVD). In addition to their potential technological use, the formation of nanodiamonds is of great scientific interest. While bulk graphite is more stable than bulk diamond at normal pressure and temperature, modeling has predicted that nanometer-sized particles of diamond could be thermodynamically favored at these conditions as a result of surface energy considerations [1]. However, nanodiamonds are still typically formed at extreme pressures and/or temperatures [2].
Here, we show that nanodiamonds can be produced at near ambient conditions (atmospheric pressure and less than 100 ^oC) by gas-phase dissociation and homogeneous nucleation in a novel microplasma process [3]. Microplasmas are atmospheric-pressure plasmas produced over short spatial and temporal scales that allow rapid quenching of particle growth processes [4]. To nucleate carbon clusters, mixtures of argon, ethanol, and hydrogen were continuously introduced in the microplasma. Optical emission spectroscopy (OES) indicated the presence of C₂ and atomic hydrogen species, both of which have been previously linked to CVD diamond growth. In situ aerosol measurements confirmed that carbon nanoparticles were formed with the particle diameter and number concentration dependent on the H₂ gas chemistry. Materials analysis was carried out by collecting the nanoparticles and characterizing by UV micro Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM). We find that a mixture of sp² and sp³ carbon is formed in our process, including nanodiamonds with sizes less than 3 nm in diameter and crystal structures corresponding to known phases of diamond including cubic, and the more rare lonsdaleite and n-diamond. The sp³ fraction increases with the addition of H₂ gas, consistent with etching of the non-diamond sp² fraction and stabilization of the nanodiamond product. The formation of nanodiamonds at near ambient conditions by gas-phase nucleation may allow new technologies to be realized such as polymer processing, and help explain their existence in the cosmos.
1. P. Badzaig, W. S. Verwoerd, W. P. Ellis, and N. R. Greiner, Nature 343, 244 (1990).
2. V. N. Mochalin, O. Shenderova, D. Ho and Y. Gogotsi, Nat. Nanotech. 7, 11 (2012).
3. A. Kumar, P. A. Lin, A. Xue, B. Hao, Y. K. Yap, and R. M. Sankaran, Nat. Comm., in press.
4. P. A. Lin and R. M. Sankaran, Angew. Chem. Int. Ed. 50, 10953 (2011).

The growth of B-doped diamond on foreign substrates requires a “seeding” substrate-pretreatment whereby diamond nanoparticles (seeds) are distributed across the substrate surface and act as nucleation sites to initiate the diamond growth [1]. These commercially available monodispersed diamond seeds [2] are undoped. Hence, if they remain undoped after growth of a B-doped diamond film, they will act as localized non-conductive areas at the interface of the film - substrate and thus will form a resistive barrier. This barrier can become crucial for applications using current transport from the diamond film (structure) towards the underlying substrate. Since the industrial demand for smooth, thin and pinhole-free diamond layers as electrodes calls for a high seeding density which thus adversely affects the interfacial resistance, a study of the electrical evolution of the seeds during the growth as well as the impact of the seeding density on the interfacial resistance of the diamond film is of major importance.
In this work we probe the spatial resistivity variations in the interfacial layer of B-doped diamond films with a spatial resolution of ~ 1 nm using scanning spreading resistance microscopy (SSRM) [3]. Key in our approach is the use of in-house fabricated ultra-sharp conductive diamond tips since metal tips wear off rapidly during SSRM mapping and suffer from poor resolution. Within the SSRM analysis, we show that the undoped diamond seeds clearly remain non-conductive, despite their exposure to a B-rich thermal treatment. Additionally, we use a dedicated four-point-probe (4PP) configuration to measure the influence of the seeding density for the current flow perpendicular to the film&’s surface. Our results clearly show that a highly dense seed layer exhibits a three orders of magnitude higher interfacial resistance than a low-density seed layer.
The SSRM electrical maps show that when scanning over a seed versus the surrounding grown grain the measured resistance is increasing by >4 orders of magnitude, up to 100 GOmega; from 1 MOmega; for the grain. In the corresponding topography map, the grown-diamond regions (grains), the grain boundaries and the individual seeds are clearly distinguishable. Seed-clusters of ~20-50 nm which are embedded in the interfacial area of the diamond film, are primarily observed but also the ~5 nm individual diamond nanoparticles that each cluster is composed of, can be identified. Furthermore, based on the 4PP results, we present a simple model to calculate the interfacial resistance and the film&’s additional thickness to be grown in order to arrive at a closed layer, according to the seeding density and seed size. This model defines the optimized seed layer based on the desired properties of the diamond film in terms of conductivity and thickness.
References
[1] V. N. Mochalin et al., Nat. Nanotechnol. 7 (11), 2012.
[2] E. Osawa. Pure Appl. Chem. 80 (1365), 2008.
[3] P. De Wolf et al., Appl. Phys. Lett. 66 (1530), 1995.

Highly boron-doped nanocrystalline diamond (NCD:B) thin layers are a quite promising alternative to conventional oxide-based transparent electrodes in micro-opto-electromechanical systems (MOEMS). Such films can serve as an advanced transparent p-type contact demonstrating specific conductivities up to 100 (Omega; cm)-1 [1]. Furthermore, the combination of NCD with either AlN or lead zirconium titanate (PZT) transparent piezo-actuators allows for microfabrication of mechanically stable, membrane-based micro lenses capable to operate at high repetition rates in harsh environments.
In this work, we report on NCD:B(300 nm)/AlN(300 nm) micro lenses equipped with radially segmented integrated actuators, which offer the possibility of free aspheric deformation of the lens surface. This feature is quite beneficial for tunable micro-optical components, e.g. for fine focus adjustment along with wave front or aberrations corrections as demanded in complex optical systems. In order to fabricate such devices, AlN layers were deposited by RF magnetron sputtering at room temperature on Si(100) substrates. The NCD:B films were prepared on the AlN/Si templates using a new seeding technique in combination with plasma enhanced chemical vapour deposition at 640 °C. Trimethylboron was added to the gas phase with a boron/carbon ratio of 3000 ppm resulting in boron concentration of ~10E21 cm-3.
Such bilayer structures were used to fabricate circular micro lenses consisting of AlN thin film actuator controlled through radially arranged multisegment diamond electrodes. The actuation performance of these NCD:B/AlN micro lenses were studied statically and dynamically using white light interferometry (WLI) and laser Doppler vibrometry (LDV), respectively. For the static characterization, two opposing sectors of the micro lens were DC actuated in order to achieve symmetric and asymmetric deformations of the lens surface. In these experiments, a maximum deflection of ~0.12 µm was recorded between actuated and non-actuated stages [2]. For the dynamic measurements, a sinusoidal signal with amplitude of 9 V at 110 Hz was applied to the actuators. A maximum aspheric surface deflection amplitude of ~0.1 µm was obtained, proving the independent functionality of multi-sector actuators [1].
In addition, PZT/NCD:B heterostructures have been fabricated and thoroughly analyzed with the aim to reduce the lens actuation voltage. PZT thin films were deposited by RF magnetron sputtering at 300 K. Afterwards the PZT films were annealed at 700 °C in an oxygen atmosphere to improve structural and piezoelectric properties. Processed PZT/NCD:B unimorph structures were characterized towards their optical, mechanical and piezoelectrical properties by means of optical transmission, bulge test, vibrometry and d33-piezoelectric measurements.
References
[1] V. Zuerbig et al., Diamond Relat. Mater., 38 (2013) 101.
[2] V. Zuerbig et al., IEEE Transducers & Eurosensors XXVII, (2013) 2317.

In the carbon universe a large number of different nanostructures can be found. Besides the fullerenes and carbon nanotubes this includes also nanoscale diamond and the so-called diamondoids. Their unique structures results in very special properties, a distinct reactivity and numerous (potential) applications for all these materials.
On the nanoscale, energetic differences between these allotropes vanish and transformations, namely on surfaces, become possible. It was shown, that e.g. nanoscale diamond can be transformed into (partially) graphitized objects. This process begins with the formation of small graphene-like structures on the nanoparticles&’ surface by surface reconstruction and can be induced by electron irradiation or thermal annealing. Recent XPS studies revealed the underlying structural changes at the initial stages of this transformation.[1]
Here, we discuss the structure and chemistry of different types of diamond nanomaterials. It turns out that the surface of diamond nanoparticles can be treated like an organic compound in many cases - enabling a vast portfolio of chemical transformations.[2]
Special emphasis will be given to the resulting surface chemistry of surface annealed nanodiamond.[3] Reactions like arylation using diazonium salts, Diels Alder, Bingel-Hirsch and Prato reaction on the fullerene-like surface structures can be successfully applied for the controlled surface modification of nanodiamond and the grafting of complex functional moieties.[4]
[1] T. Petit, J.-C. Arnault, H. A. Girard, M. Sennour, P. Bergonzo, Phys. Rev. B 2011, 84, 233407.
[2] A. Krueger, D. Lang, Adv. Funct. Mater. 2012, 22, 890-906.
[3] T. Meinhardt, D. Lang, H. Dill, A. Krueger, Adv. Funct. Mater. 2011, 21, 494; G. Jarre, Y. Liang, P. Betz, D. Lang, A. Krueger, Chem. Comm. 2011, 47, 544; P. Betz, A. Krueger, Chem. Phys. Chem. 2012, 13, 2578; D. Lang, A. Krueger, Diamond Relat. Mater 2011, 20, 101.
[4] G. Dördelmann, T. Meinhardt, T. Sowik, A. Krueger, U. Schatzschneider, Chem. Comm 2012, 48, 11528; M. Hartmann, P. Betz, Y. Sun. S. N. Gorb, T. K. Lindhorst, A. Krueger, Chem. Eur. J. 2012, 18, 6485.

Fluorescent nanodiamond particles have attracted important attention as a possible drug carriers for targeted cellular delivery, allowing at the same time particle tracking and even bimolecular sensing. In the centre of this application stands brightness of fND luminescence as well as the diamond surface that is used to attach various complex biomolecules [1,2]. Recently surface fluorination from gas phase has been used to stabilize NV- charge state luminescence. However, the type and structure of the F bod at the surface place detrimental influence on fND brightens, In our work we have developed a novel F- gas and liquid HF fluorinated process, allowing using novel chemistries to prepare- fND surfaces with specific bonding structures (F-fND). For example CF2 bonds or polymeric structure would lead to a surface charging and quenching of NV luminescence. The surface fluorinated was optimized based on the feedback from single particle NMR, XPS and NV luminescence characterization including anti-bunching time correlated experiments, determining the NV centre distribution, surface bond architecture and surface band bending. The obtained F-fND , where F is inserted by nucleophilic addition to benzene rings and prepared at the fND surfaces, were highly bright and forming stable colloids in biological buffers. The F-fND, grafted with peptides that is overexpressed in cancer cells have been targeted o the best cancer sells an used for intracellular bimolecular sensing.
[1] Petrakova at all, Advanced Functional Materials , 22, 2012
[2] Havlik at al, Nanoscale, 5, 2013

While many of the applications for diamond nanoparticles (nanodiamonds) are facilitated by their high specific area and adsorption capacity, future development of nanodiamond-based technologies are contingent on our ability to predict and moderate inter-particle interactions. It has been well establish that, like many other nanoparticles, the aggregation of nanodiamond is moderated by the properties of individual surface facets (such as the surface electrostatic potential, surface structure, and functionalization). However, although it is now possible to produce stable suspensions of ~3.0 nm nanodiamonds, with a narrow size distribution, no method has been identified to engineer the particle shape, nor to purify the samples based on the prevalence of different types of surface facets. Structural polydispersivity in nanodiamond samples is persistent. Therefore, in this presentation we have used facet-facet interactions potentials obtained from electronic structure simulations to parameterize a model and simulate the aggregation and assembly of ensembles of different types of nanodiamonds at the meso-scale. We will show how variations and distributions in size and shape affect the aggregation behavior, and the ultimately determine the global properties of the aggregates (such as crystalinity and porosity).

When small particles of detonation nanodiamond (DND) with 4-5 nm in diameter were found dissolved in water in 2005, we were much surprised and sought to explain the unlikely phenomenon in terms of the surface interaction with water. Korobov first presented evidence for particularly strong hydration with the surface of disintegrated DND by observing an endothermic peak at -8 degrees centigrade by DSC. In the same year Barnard found strong negative Mulliken charges mainly on the spontaneously graphitized {111} facets, which should provide a good proton-accepting sites for H-bonding with water molecules.
Then there arose two pieces of inconsistencies against the OHhellip;e solvation theory. One difficulty is to assign continuously polarized hydration layer near the surface to a single and separate DSC endothermic peak. The other is good performance of our DDS experiments using DND as the drug carrier. Bonding between doxorubicin drug molecule and carrier particle has been considered similarly Coulombic N+hellip;e, where N+ represents hydrochloride of primary amino group in the drug molecule. However, no side effect by the notorious drug was ever observed, which would be unlikely if the drug molecules were carried through polar blood while simply bound by electrostatic force to the surface of DND.
Our recent success in isolating, producing and characterizing the true primary particles of DND, 3.0±0.6 nm in diameter (PPDND) , allowed us to straighten the confusion on the surface structure and its interactions. Larger DND particles used in the earlier stages of our work proved to have been mixtures of oligomers with the primary particles having large particle-size distribution with standard deviation of about 6nm. Thus, we are now ready to solve a number of pending problems.
As a part of our study directed towards straightening the long confusion in the research of DND, here we propose that intercalation in the space created by graphitization of one (or two) layers of carbon atoms on the {111} facets of PPDND, takes place with solvent and solute molecules through holes created in the graphitic surface. The existence of holes for intercalation has not been proved by experimental approaches but geometry optimization of real-size models of PPDND provides supporting evidence. The intercalation hypothesis well explains new DSC results of PPDND and also fits the DDS performace. On the other hand, diffuse hydration layer on the surface must be responsible for dissolution of PPDND in water. It is also suggested that black color of aqueous colloid is caused by the layer of intercalated water beneath the graphene (oxide) surface.

The development of new lubricant and lubricant additives are critical from both energy conservation and environmental impact viewpoints. For example, total frictional losses in a typical diesel engine can be greater than 10% of the total fuel energy. Current oil-based technologies, which were developed with a focus on wear elimination, rely heavily on sulfur, phosphorous and/or chlorine based additives that have a propensity for bioaccumulation and environmental toxicity. Disposal and inadvertent discharge of oil-based lubricants is another major world-wide environmental concern.
To be presented in this talk are the results of several experimental and modeling studies that have used complementary approaches to compare the efficacy of different carbon nanoparticles in various solvents and under different sliding conditions on friction and wear reduction. One study used block-on-ring and ring-on-disk experiments to test the tribological properties of polyalphaolefins (PAO) and engine oils containing small amount of nanocarbon additives. Comparative analysis of coefficient of friction, wear and surface roughness was performed for PAO containing nanodiamond particles, detonation soot (a mixture of nanodiamonds and nanographitic structures), nanocarbon onions, carbon nanotubes and nano-graphene flakes. Synergistic compositions of the nanocarbon particles with molybdenum dialkyldithiophosphate (MoDDP) were also investigated. It was concluded that nanodiamond particles outperformed their sp2 counterparts in terms of reduced friction and wear. Based on roughness studies, the most probable mechanism is polishing of surface asperities in combination with the protective action of MoDDP. In a parallel effort the tribological performance of liquid-nanoparticle-interface systems was characterized using a quartz crystal microbalance. It was observed that 5nm nanodiamonds with a negative zeta potential demonstrate more efficient lubrication in water suspensions compared to positively charged nanodiamonds of the same size. Results from related experiments that are examining the influence of different textures and roughness on tribological performance will also be discussed.
To better understand the details of these various mechanisms, and how these details relate to nanodiamond and surface structure and properties, we have been carrying out molecular dynamics of solvated nanodiamonds and related nanocarbon structures.. Simulation results for nanodiamonds with different surface functional groups, agglomerated nanodiamonds and nanodiamonds reacting with metal surfaces during sliding will be mentioned, as well as studies using non-aqueous solvents.
Support for these studies comes from the National Science Foundation through the Division of Materials Research and the G8 Research Council through the National Science Foundation under Grant No. CMMI-1229889

Nanodiamonds synthesized by detonation of explosives have emerged as a promising additive to base lubricants to reduce wear and friction. Several mechanisms have been suggested for this observation, including creation of protective surface films, surface roughness reduction by abrasion and by filling in surface regions between asperities and by acting as spacers that roll and slide between contacting surfaces.
To better understand the details of these various mechanisms, and how these details relate to nanodiamond and surface structure and properties, we have been carrying out molecular dynamics of solvated nanodiamonds between sliding interfaces. Our initial simulations have focused on understanding the role of particle shape (round versus facetted) on the ordering of the water layer surrounding the nanodiamond, the motion of the nanodiamond (sliding versus rolling), and correlation time of the nanodiamond motion as a function of pressure, and the interface sliding speed and separation. For example, in preliminary simulations it was observed that a spherical particle translates faster in shear flow than an octahedral particle of comparable size, suggesting that frictional drag may be higher on faceted nanodiamond particles compared to more spherical particles. Simulation results for nanodiamonds with different surface functional groups, agglomerated nanodiamonds and nanodiamonds reacting with metal surfaces during sliding will be discussed, as well as studies using non-aqueous solvents.
This material is based upon work supported by the G8 Research Council through the National Science Foundation under Grant No. CMMI-1229889

We have developed a ReaxFF reactive force field to describe Li interactions with carbon based materials. The ReaxFF force-field parameters for Li-C systems were optimized against a density-functional theory (DFT; with van der Waals corrections) based training set, containing a collection of data (energies, geometries, charges etc.) related to adsorption and diffusion of Li on graphene and in graphite. The ReaxFF reactive force field accurately reproduces the adsorption energies for Li on pristine graphene, intralayer Li migration barriers in graphite and formation energy of stage I (LiC6) compounds in graphite in agreement with DFT data. For ‘out-of&’ training set validation we compare Li diffusion in the direction perpendicular to graphene with single and double-vacancy defects, formation energy of 1, 2 ,3 and 4 Li atom clusters over pristine graphene, graphene with single and di-vacancy defects, 5-8-5 reconstructed graphene and 5-5-5-7-7-7 reconstructed graphene given by ReaxFF and DFT calculations. The voltage profile for the Li-graphite system as a function of Li concentration obtained from grand canonical Monte Carlo simulations using ReaxFF, matches experiment and DFT data. ReaxFF describes the in-plane Li ordering and interlayer separations for stage I and II compounds in good agreement with previous DFT studies and experiment. We study Li intercalation in presence of vacancy defects in graphite and find that the presence of vacancy defects increase the ratio of Li/C and shifts the voltage profile downwards, both in proportion to the number of vacancy defects. Li intercalation and diffusion kinetics in Carbon Onions was investigated for potential applications in batteries and electrochemical capacitors and we report a different loading behavior/voltage profile for these Carbon Onions as compared to graphitic systems. The Voltage vs Li concentration for Carbon Onions has a ‘saw tooth&’ shape whereas the voltage profile for graphitic systems consists of plateaus. The free energy landscape for Li diffusion between different layers of Carbon Onions through vacancy defects were explored using metadynamics simulations.

Nanodiamond powder produced by detonation synthesis has a great potential in different applications [1]. However, the structure and structure-properties relations for this unique nanomaterial are still debated [2]. Even less is known about the details of nanodiamond interactions with the environment at the atomistic scale. For many important applications, including drug delivery, composites, and many others, it is important to understand the interactions of nanodiamond particles with surrounding media, which can be a solvent, or a polymer or metal matrix, etc. We present an atomistic study of the interactions of nanodiamonds with different surface chemistry with liquids in colloidal solutions. Structural and thermodynamic parameters of nanodiamond solvation will be discussed. This knowledge will advance our understanding of nanodiamond behavior in different liquids and polymers, which is important for drug delivery and composite applications.
1. Mochalin, V. N.; Shenderova, O.; Ho, D.; Gogotsi, Y., The properties and applications of nanodiamonds. Nature Nanotechnology 2012, 7, 11-23.
2. Osawa, E.; Ho, D., Nanodiamond and its application to drug delivery. J Med Allied Sci 2012, 2, 31-40.

According to Bowden&’s fusion theory on the origin of friction, it develops when microscopic asperities on a pair of surfaces in relative motion touch and press against each other to fuse and bind under the magnified force. Lubrication oil film that forms between the asperities under the boundary condition readily breaks, hence oil was a wrong choice to which we have adhered too long since the time of Romans. In addition, the used lubricant oils are widely recognized as one of the worst environmental hazards. However, Bowden apparently could not find replacement for oil after he solved the mystery posed by Leonardo da Vinci. Solid layered lubricants like graphite and MoS2 are no better, giving high frication constants (mu;). An ideal lubricant to substitute oil should prohibit direct contacts between the surfaces in relative motion, have very low mu;, be costly competent against oil, environmentally friendly, hopefully disposable, biocompatible, and does not cause any health risk.
In 2008, we proposed dilute aqueous colloidal solution of primary particles of detonation nanodiamond (ND) as the candidate for the general lubricant liquid of the next generation. Quasi-spherical ND particles are expected to play double roles, one as spacers, or nano ball-bearings, to prevent direct collision of asperities and also as roller to move the surfaces apart. Rolling friction is generally close to zero. NDs satisfy other requirements for nanolubricants such as hardest material, chemical inertness, low cost and non-toxicity. One remaining condition to be considered would be the ubiquity of nanospacers: enough number of spacer should be available near asperities whenever needed. We had anticipated high number density of single-nano particles. For example, our 3.2 nm ND is estimated to contain particles in the order of 1018, or Exa (thousand times Peta), per gram. If we use 0.01wt% aqueous solution of 3.2 nm ND as lubricant, 1mu;l of the solution is supposed to contain as many as 10 million particles, which seem sufficient. We tested the premise on a commercial ball-on-disk friction tester under a load of 40mN. We did obtain a very low mu; value of 0.007, but only under a ND concentration of 1%.
In this presentation we discuss two progresses: further characterization of 3.2nm primary particles of detonation nanodiamond and extensive re-designing of the commercial low-load friction tester that we used in our first experiments on the nanospacer lubrication. In the past the small load during the reciprocal movement were assumed constant, but actually varies significantly on microsecond time scale. In the improved version the effective load is considered variable. Hence the friction process is now treated as a 3D phenomenon. Friction process was analyzed in terms of Lissajous curve.

Heavy metal pollution, caused by the waste streams of metal plating facilities, mining operations, and tanneries are not biodegradable and tend to accumulate in living organisms, causing various diseases and disorders to the nervous, immune, reproductive and gastrointestinal systems.1 Electrochemical method is one of the most favorable techniques for the simultaneous determination of environmental pollutants because of its low cost, high sensitivity and easy operation. Here, we explore diamond nanowire (DNW) electrode for the electrochemical deposition of samarium hexacyanoferrate2 (SmHCF) as electroactive materials for chemical sensors. The DNW electrode has been synthesized on silicon substrate by N2-based microwave plasma enhanced chemical vapor deposition. The SmHCF deposited on the surface of the DNW electrode by potential cycling from +0.8 to -0.2 V. The SmHCF found to grow on the surface of the DNW electrode with each potential cycle, as revealed by the change of peak currents with each cycle. A well-separated voltammetric peaks for the simultaneous detection of Cd2+, Pb2+, Hg2+, Cu2+, and Zn2+ toxic metal ions are obtained using SmHCF/DNW electrodes in differential pulse voltammetry measurements. Consequently, the DNW electrode with large surface area3, good chemical stability, and SmHCF makes the electrode an efficient chemical biosensor.
Keywords: N2 incorporated diamond nanowire electrode, Samarium hexacyanoferrate, Cyclic voltammetry, Differential pulse voltammetry, Heavy metal ion

Size is a defining characteristic of nanoparticles; it influences their optical and electronic properties, as well as their interactions with molecules and macromolecules. Producing nanoparticles with narrow size distributions remains one of the main challenges to their utilization. At this time, the number of practical approaches to optimizing the size distribution of nanoparticles in many interesting materials systems, including diamond nanocrystals, remains limited. Here, we introduce a large-scale approach to rate-zonal density gradient ultracentrifugation (DGU) to obtain monodispersed fractions of nanoparticles in high yields.
Diamond nanocrystals synthesized by detonation protocols - so-called detonation nanodiamonds (DNDs) - are promising systems for drug delivery, photonics, and composites. DNDs are composed of primary particles with diameters mainly < 10 nm and their aggregates (ca.10-500 nm). We use DGU fractionation to separate a highly concentrated and stable solution of DNDs into different size ranges. Fractions were characterized with dynamic light scattering, analytical ultracentrifugation, transmission electron microscopy and powder X-ray diffraction. Our method paves the way to in-depth studies of the physical and optical properties, growth, and aggregation mechanism of DNDs. Applications requiring DNDs with specific particle or aggregate sizes are now within reach.
As an example of applications enabled by the precise size separation of nanodiamonds, DGU was used to indirectly control the number of fluorescent nitrogen-vacancy (NV) centers in high-pressure high-temperature (HPHT) nanodiamonds through fractionation. Nanodiamonds of a broad size distribution were obtained by ball-milling commercially available micrometer-sized HPHT diamonds. The particles were separated by DGU into size-controlled fractions and subsequently subjected to He+ irradiation to increase the content and enhance the uniformity of NV centers within the particles. Using a standard confocal setup, we analyzed the average number of NV centers per crystal, and obtained a quantitative relationship between the nanodiamond particle size and the NV number per crystal. In particular under the experimental conditions described in this work, diamond nanoparticles around 37 nm in size contained about one NV center per particle on average. The number of NVs per crystal decreased dramatically at sizes below 37 nm and increased rapidly at sizes above 37 nm. Since the number of NV centers per particle can be mapped to the particle size, our study suggests that particle size separation can serve to control the number of NV defects within a crystal. Our work is a milestone towards controlling the size-dependent properties of other defect color centers in nanodiamonds, which enables bottom-up strategies for the placement and self-assembly of particles with specific number of color centers.

Thin nanocrystalline diamond foils used for H- stripping at the Spallation Neutron Source (SNS) at ORNL are fabricated via plasma enhanced chemical vapor deposition. Under SNS operating conditions, these carbon foils undergo a substantial phase change with a concomitant volume change. However, the foil remains sufficiently robust such that it does not distort grossly or disintegrate. To investigate the structural characteristics of irradiated diamond foils, we have used a combination of high-resolution TEM imaging and electron energy loss spectroscopy. For our testing, damage is induced in foils through the use of a 30 keV electron beam that simulates the foil thermal load corresponding to SNS proton operations; this avoids the need to examine activated materials. We have characterized the structure of the foils at differing irradiation fluence. In the as synthesized condition, foils are composed of diamond grains with diameter as small as ~10 nm diameter. For the irradiated material, preliminary HRTEM imaging suggests possible formation of carbon nano onions.

Diamond nanoparticles or nanodiamonds (NDs) produced by detonation synthesis have attracted a lot of attention over the last years. Because its potential applications are numerous, studies of this material aim to understand, control and tailor its physical and chemical properties which are given by the combination of an inert diamond core with a surface rich in functional groups [1]. Indeed ND crystallites are composed of diamond cores of a few nanometers in diameter, partially or completely covered by a thin layer of graphitic and / or amorphous carbon, and bearing carboxyl-, hydroxyl and carbonyl functionalities on the surface.
Raman spectroscopy is commonly used for the characterization of those detonation nanodiamonds. When observable, the Raman spectrum of those nanoparticles is usually composed by a broadened and downshifted first-order Raman mode of the cubic lattice and a broad peak at about 1600 - 1650 cm-1. Previous studies have shown that this broad peak seems to be sensitive to the NDs surface chemistry. However, the assignment of this peak is still unclear [1,2 and references herein]. In this study, different chemical and thermal treatments were carried out in order to selectively modify their surface chemistry and track the resulting changes in the Raman spectrum.
Detonation NDs (provided by NanoCarbon Research Institute Ltd) were either hydrogenated using a microwave plasma [4] or annealed under air or vacuum to induce surface carboxylation or graphitisation [5]. Various visible as well as UV excitation lines were used for Raman analysis. Using excitation in the deep UV range, analysis conditions (atmosphere and incident power) must be chosen carefully. Even moderate laser powers can lead to strong and irreversible modifications in the observed spectra. To date, no clear correlation between the line shape of the spectra and the H and/or O content of the particle shells have been obtained. Only a clear signature of a “graphitized” surface has been observed. Heating in H2 atmosphere may promote sp2 bonding.
1. V. N. Mochalin et al, Nat. Nanotechnol. 2012, 7, 11.
2. V. Mochalin et al, Chem. Mater. 2009, 21, 273.
3. S. Osswald et al, J. Am. Chem. Soc., 2006, 128, 11635.
4. H. A. Girard et al, Diam. Relat. Mater. 2010, 19, 1117.
5. T. Petit et al, Nanoscale 2012, 21, 6792.

Nanodiamond particles (ND) have received much attention in biotechnology for use as sensing devices, chromatographic separation, and drug delivery [1]. ND possess desirable properties for developing drug delivery systems including low cell toxicity, biocompatibility, stable structure and surface chemistry which can be modified for different environments. The potential for ND in delivery and sustained release of anticancer drugs has been recently demonstrated, however, much is still unknown about the specifics of adsorption/desorption with different ND purity, surface chemistry, and agglomeration state. Understanding the details of adsorption and desorption on ND are critically important for the design of the ND drug delivery systems. Recently, we reported on the adsorption of doxorubicin and polymyxin B on NDs with different surface chemistries [2]. Here, we extend this study to include a broader range of drugs and conditions. These studies will result in a better understanding of the mechanisms of drug adsorption and contribute to a rational design of new nanodiamond enabled theranostic platforms.
1. Mochalin, V. N.; Shenderova, O.; Ho, D.; Gogotsi, Y., The properties and applications of nanodiamonds. Nature Nanotechnology 2012, 7, 11-23.
2. Mochalin, V. N.; Pentecost, A.; Li, X.-M.; Neitzel, I.; Nelson, M.; Wei, C.; He, T.; Guo, F.; Gogotsi, Y., Adsorption of Drugs on Nanodiamond: Toward Development of a Drug Delivery Platform. Molecular Pharmaceutics 2013, 10, 3728-3735.

Nanodiamonds (NDs) are promising nanoparticles for biomedicine applications [1]. They are scalable with sizes ranging from 100 nm down to 5 nm. NDs enable covalent grafting of various chemical moieties on their surfaces [2] resulting in stable colloidal aqueous solutions. Based on our experiments, this talk will emphasize other assets of NDs essential for biomedicine: their low toxicity, the tuning of their surface chemistry, their tritium labelling or their covalent grafting with peptide nucleic acids (PNA).
The potential of NDs as negative control in nanotoxicology studies will be demonstrated. Cytotoxicity and genotoxicity of HPHT NDs (20 nm/100 nm) were investigated on six human cell lines representative of potential target organs. NDs effectively entered the cells but any significant cytotoxic or genotoxic effects were observed up to an exposure dose of 250 mu;g/mL [3].
The intrinsic surface properties of detonation NDs can be tuned playing with their surface chemistry allowing a control of their surface charge. Behaviours of plasma hydrogenated (H-NDs) and surface graphitised (sp2-NDs) nanodiamonds dispersed in aqueous solutions will be compared [4, 5]. Besides enhanced colloidal properties, electron transfer arising from H-NDs was also found to confer therapeutic properties to NDs that could be used for biomedical applications.
Radioactive labelling of nanodiamonds is a promising approach to ensure their tracing for biolabeling or biodistribution studies. Up to now, no radioactive labelling was reported yet. Detonation nanodiamonds (3H-ND) were tritiated (β- emitter) using a microwave plasma reactor. Sequential radioactivity measurements of 3H-ND at different temperature thresholds during an air oxidation showed that stable radioactive labeling comes not only from surface C-3H bond but also from the diffusion of 3H deep inside the diamond lattice which represents 25% of tritium atoms. These results demonstrate the excellent stability of tritium incorporated into NDs.
HPHT 20 nm NDs were covalently grafted with peptide nucleic acids (PNA). The original functionalization route is based on an optimized amidation of ND carboxylic acids groups. ND-PNA conjugates were validated through a successful recognition of complementary DNA in a mixture, showing their efficiency toward nucleic acid detection [6]. Such nucleic acid functionalized NDs may contribute to the development of new biomedical tools towards genetic diseases, genomic research or early cancer diagnosis. All these results strongly support the huge potential of NDs for human nanomedicine especially nanodiamond can act as an active nanoparticle.
References
[1] V. N. Mochalin et al., Nat. Nanotech. 7 (2012) 11
[2] A. Krueger et al., Adv. Funct. Mater. 22 (2012) 890
[3] V. Paget et al., Nanotoxicology DOI:10.3109/17435390.2013.855828
[4] T. Petit et al., Nanoscale 5 (2013) 8958
[5] T. Petit et al., Nanoscale 21 (2012) 6792
[6] C. Gaillard et al., RSC Advances DOI:10.1039/C3RA45158E

The deterministic coupling of single quantum emitters to micro-photonic cavities is considered an important step towards integrated solid-state devices for quantum information processing. In this context, color centers in diamond, e.g. nitrogen- (NV) or silicon-vacancy (SiV) centers have recently attracted significant interest due to their extraordinary properties like long spin coherence times or narrow bandwidth emission, respectively. We here present two routes for the deterministic coupling of single color centers to optical cavities at the micro- and nano-scale:
In a first approach we demonstrate coupling of a single NV center in a nanodiamond to a fiber-based, tunable, Fabry-Perot-type microcavity at room temperature. Making use of the NV center&’s strongly broadened emission we operate in the regime of phonon-assisted cavity seeding and realize a widely tunable, narrow-band single photon source [1]. A master equation model well reproduces our experimental results and predicts a transition into a Purcell-enhanced emission regime at low temperatures where up to 65% of the NV emission would be channeled into the cavity mode for our given experimental parameters. We show that such a fiber-based cavity works well at cryogenic temperatures. Further reducing scattering losses from the nanodiamonds could enable schemes for cavity-enhanced spin measurements, creation of entangled states or high repetition rate single photon sources.
As second approach we use photonic crystal nano-cavities [2] directly fabricated at the predetermined position of single Silicon-Vacancy (SiV) centers in a single crystal diamond membrane. The cavities can be aligned both to the emitter&’s position and dipole orientation. We observe a large Purcell enhancement of the spontaneous emission visible from a factor of 19 increase of the zero phonon line and a reduction of the SiV center spontaneous emission lifetime by a factor of 2. Furthermore, we investigate the deterministic implantation of NV centers into photonic crystal cavities with high spatial precision using a nano-implantation technique based on a pierced AFM tip [3].
[1] R. Albrecht, A. Bommer, C. Deutsch, J. Reichel, and C. Becher, Coupling of a Single Nitrogen-Vacancy Center in Diamond to a Fiber-Based Microcavity, Phys. Rev. Lett. 110, 243602 (2013).
[2] J. Riedrich-Möller, L. Kipfstuhl, C. Hepp, E. Neu, C. Pauly, F. Mücklich, A. Baur, M. Wandt, S. Wolff, M. Fischer, S. Gsell, M. Schreck, and C. Becher, One- and two-dimensional photonic crystal micro-cavities in single crystal diamond, Nature Nanotechnology 7, 69 (2012).
[3] S. Pezzagna, D. Wildanger, P. Mazarov, A.D. Wieck, Y. Sarov, I. Rangelow, B. Naydenov, F. Jelezko, S.W. Hell, and J. Meijer, Small 6, 2117 (2010).

NV centres in diamond display remarkable spin properties, even at room temperature, and thus show promise for future quantum technologies. Their broad phonon-assisted emission spectrum, with only 4% of the light entering the zero phonon line is considered be a hindrance to this. Optical Microcavities can provide a way to manipulate their emission properties and interface with large-scale photonic networks in the future.
We report the coupling of NV centres in nanodiamond to tunable open-access optical microcavities. The microcavities are formed from Fabry-Perot mirrors with hemispherical features on one mirror, which are independently manipulated. Arrays of hemispherical features are constructed by Focused Ion Beam milling, with subsequent high-reflectivity mirror coating. The narrow ion beam diameter allows us to pattern features well below the wavelength scale. As a consequence we obtain smooth features with radii of curvature on the micron scale and thus ultra-small cavity mode volumes. This is essential for the enhancement of the light-matter interaction. When coupling to these small cavities, we observe profound changes in the observed emission spectrum of the NVs at room temperature, such that up to 60% of the photons are collected from a single cavity mode. We demonstrate coupling to cavities with mode volumes down to 10 cubic wavelengths. With precise control over the cavity length, the cavity modes are tuned across the entire wavelength range of the NV spectrum. We also show how, using scanning confocal microscopy, one can observe spatial feeding of the NV emission into different cavity modes.
Continuing refinement of the fabrication process will allow access to even smaller mode volumes. It is ultimately hoped that one can observe a change in the rate of spontaneous emission of the NV when coupled to the cavity, the Purcell effect. Efforts towards this, both and room and cryogenic temperatures, will be discussed.

An important goal of materials science is the development of interfaces that integrate the functions of living cells and materials. Nature has given us plenty of ideas on how to build composites and organized structure. The structure of a given biomaterial is crucial, when determining the cell response, and respectively the variants for its biomedical applications. Nanodiamonds satisfy the requirements of a modern material, providing strength, robustness and stability, on one hand, as well as many options for chemical surface modification, tailoring its properties and combining it with other materials, on the other hand. Physical properties of materials, in particular elastic modulus, hardness and surface topography have recently been shown to be potent factors to modulate stem cell behavior. In this study, we present technology for production of nanodiamond/ polymer composite, as well as preliminary chemical treatment of nanodiamond particles, developed for screening the effects of material physico-chemical properties on cells behavior. The obtained composites (PPHMDS) by plasma polymerization (PP) of a mixture of hexamethyldisiloxane (HMDS) monomer and detonation generated nanodiamand particles (DNDs) on solid substrate are discussed. By mixing monomer (hexamethildisiloxan, HMDS) with different nanofillers of DND and varying concentration the optimal selection could be achieved. These provide the possibility to study correlation between composition, sensitivity and selectivity to analyzing substance within the expanded range. Results from nanoindentation measurements show that by changing the amount of DNDs filler in polymer matrix the properties of the composite, particularly hardness and module of elasticity, could be influenced. The vibrational dynamics of the composites were investigated using Raman and Fourier transform infrared spectroscopy (FTIR). Static water contact angle of the composites surface was measured with Easy Drop Shape Analysis System Wetability. Surface topography and chemistry were studied by AFM and XPS respectively. Our results suggest the potential of using DND-based polymer composites for application in engineering implantable scaffolds and devices.

Integrated quantum hybrid devices, built from classical dielectric nano-structures and individual quantum systems promise to provide a scaleable platform to study and exploit the laws of quantum physics. On the one hand there are novel applications, such as efficient computation [1], secure communication and measurements with unreached accuracy. On the other hand hybrid devices might serve to explore the limits of our understanding of the physical world, i.e. the formalism of quantum mechanics.

In the recent years, in particular nitrogen vacancy (NV) centers in nanodiamond emerged as a promising quantum emitter for integrated hybrid devices. NV-centers are long-time stable and occur naturally in bulk diamond and nanocrystals. Apart from a triplet ground state with ultra long coherence times they provide a narrow optical transition at about 638 nm, which is capable to emit single photons even at room temperature [2].

Recent experiments on the manipulation of the NV's spin, like the demonstration of the quantum Zeno effect [3] are reviewed. Furthermore, novel results on the coupling of individual defect centers to resonant micro and nano structures are introduced [4,5]. These results pave the way for more complex devices and to realize entanglement of distant NV-centers on-chip. For this, a feasible scheme [6] which is robust against spectral diffusion [7] is discussed.

[1] T. D. Ladd, et al., “Quantum computers” in Nature, 464(7285), 2010.

[2] J. Wrachtrup, F. Jelezko, “Processing quantum information in diamond” in Journal of Physics: Condensed Matter, 18(21), 2006.

[3] J. Wolters, M. Strauss, R.S. Schoenfeld, and O. Benson, "Quantum Zeno phenomenon on a single solid-state spin" in Physical Review A 88, 020101 (2013).

[4] A.W. Schell, et al., "Three-dimensional quantum photonic elements based on single nitrogen vacancy-centres in laser-written microstructures" in Scientific reports 3, 1577 (2013).

[5] J. Wolters, et al., "Enhancement of the zero phonon line emission from a single nitrogen vacancy center in a nanodiamond via coupling to a photonic crystal cavity" in Applied Physics Letters 97, 141108 (2010).

[6] J. Wolters, J. Kabuss, A. Knorr, and O. Benson, "Deterministic Entanglement of Nitrogen Vacancy Centers using Low-Q Photonic Crystal Cavities". unpublished.

[7] J. Wolters, et al. "Measurement of the Ultrafast Spectral Diffusion of the Optical Transition of Nitrogen Vacancy Centers in Nano-Size Diamond Using Correlation Interferometry" in Physical Review Letters 110, 027401 (2013).

Doping of carbon nanoparticles by impurity atoms is central to their application. However, doping has proven elusive for very small carbon nanoparticles because of their limited availability and missing fundamental understanding of impurity stability in such nanostructures. Here, we show that isolated diamond nanoparticles as small as 1.6 nm, comprising only about 400 carbon atoms, are capable of housing stable photo-luminescent color centers, namely the silicon-vacancy (SiV) [1]. Surprisingly fluorescence from SiV is stable with time and few or single color centers are found per nanocrystal. Further on we observe a size dependent SiV emission supported by quantum chemical simulation of SiV energy levels in small nanodiamonds. Our work opens the way to investigate the physics and chemistry of molecular sized cubic carbon clusters and promises application of ultra-small non-perturbative fluorescent nanoparticle as markers in microscopy and sensing.
[1] I. I. Vlasov et al., Nature Nanotechnology.(accepted Oct. 2013)

As a wide band-gap material, nanodiamond (ND) can contain a variety of atomic defects or impurities as color centers. Some of the color centers are highly luminescent, while others are luminescent with a very low quantum yield. For NDs containing a high-density ensemble of vacancy-related defect centers, which can be readily generated by ion irradiation, they are useful as contrast agents for bioimaging both in vitro and in vivo. This lecture presents two examples of the applications by utilizing the nitrogen-vacancy (NVminus;) centers and the GR1 (V0) centers in NDs for photoluminescent imaging and photoacoustic (PA) imaging, respectively. First, we show how one can use fluorescence lifetime imaging microscopy to achieve background-free real-time imaging of the fluorescent NDs (denoted as FNDs) in living organisms such as C. elegans. With 100-nm FNDs conjugated with yolk lipoprotein complexes, our results demonstrate that the nanoparticles are useful as a biomolecular nanocarrier without significantly altering the functionality of the cargos for intercellular transport, cell-specific targeting, and long-term imaging applications in vivo. Second, we discuss our recent development of highly radiation-damaged or irradiated NDs (denoted as INDs) as a potential PA contrast agent for deep-tissue imaging. The damage with 40-keV He+ irradiation is so extensive that graphitization to some degree occurs concurrently with the generation of the GR1 centers. An average molar extinction coefficient of 4.2 M-1cm-1 per carbon atom was measured at 1064 nm. Compared with gold nanorods of similar dimensions (10 nm × 67 nm), the 40-nm INDs have a substantially smaller (by >4 orders of magnitudes) molar extinction coefficient per particle. However, the deficit is readily compensated by the much higher thermal stability, stronger hydrophilic interaction with water, and a lower nanobubble formation threshold (~30 mJ/cm2) of the sp3-carbon-based nanomaterial. No sign of photodamage was detected for the INDs after high-energy (>100 mJ/cm2) illumination for hours, indicating that the nanomaterial is well suited for long-term PA bioimaging applications.

The abilities of nanostructured carbon to afford very high electrical and thermal conductivity, good mechanical properties and high surface area with controlled pore size complement the capability of conductive polymers and ceramic materials to efficiently store high content of ions in small volumes. This makes carbon-containing nanocomposites attractive for high energy, high power and multi-functional applications. This talk will provide an overview of recent applications of nanodiamond and carbon onion powders in advanced electrodes for high energy and high power supercapacitors and batteries.

The thermodynamic stability of diamond nanocrystals considered in a number of papers, largely theoretically. Because in nanodiamond (ND) crystal of 4-5 nm size, the fraction of the surface atoms is ~15 %, the main influence to the enthalpy provide the chemical state of the surface atoms . Experimental data show enhanced ND enthalpy to 30.72 kJ / mol measured through combustion, far exceeding the difference for bulk diamond and graphite ( 1.8 kJ / mol) [1]. In this paper, we attempt to estimate the diamond nanooctahedra standard enthalpy in the approximation to the C - C, C = C and C -H bond energies. Obviously, the highest value of the enthalpy should have a diamond nanocrystals with unreconstructed (111 ) faces covered with broken ( ‘dangling&’ ) bonds, equiv; C. After the Pandey surface reconstruction the C = C bond formation take place with markedly enthalpy decrease. Finally, it is possible to consider unreconstructed monohydride (111 ) faces with a monolayer of C-H bonds formation with next dramatic enthalpy decreasing. In all cases, the energy of the atoms at the vertices and edges of the crystals was not considered. It is easy to show that the deviation of the considered nanocrystals from bulk diamond energy will increase with a decrease in the size a - the length of the edge of the octahedron. Assuming that the excess energy of the surface atoms on the unreconstructed (111 ) is 177.82 kJ/ mol, we can show that for an octahedron with a = 5 nm have excess relative the bulk diamond crystal enthalpy amounted 28.1 kJ/mol. Chemisorption of hydrogen provides significant reduction in surface energy and further reduction of the diamond nanocrystals enthalpy. Abovementioned looks as interesting and helpful approach to the size ranges consideration between higher diamantoids and diamond nanoparticles.
Moreever, according to many CVD diamond studies the hydrogen plays an important role in the diamond nucleation, because a significant decrease in the sub-nm crystals enthalpy and their surface energy takes place.
REFERENCES
[1]. G.V.Sakovich, et al. Detonation nanodiamond. Synthesis. Properties. Application. Science and Technology in Industry. 2011. # 4. PP. 53-61.

Nanodiamond has attracted great attention recently for its possible bio and medical applications mainly speaking about bio imaging and drug delivery. The feasibility lies in the superior biocompatibility and possibilities on surface conjugations. The spectroscopic advantages of nanodiamond, fluorescence and Raman, render nanodiamond a biocompatible bio marker for tracking the interaction of desired molecule with the biological systems. However, before any sensible application can be realized, the biodistribution and interaction of the nanodiamond with tissues and organs are important issues. To date, very limited number of publications exists concerning ND interaction with tissues and organs. However, the understanding of the interaction mechanisms of ND with tissues and organs is a necessary step for implementing ND&’s biomedical applications on the highest levels of biological system organization.
In this presentation, we discuss the interaction of ND of different sizes and ND in complex with biologically active molecules (proteins, drugs) with blood cells and blood proteins; with special focus on the ND with immune responsive macrophage cells, and with red blood cell (RBC) in vitro and in vivo. This allows discussing the mechanisms of ND interaction with RBC membrane, influence on the membrane structure and effects on the RBC mechanical properties, which in turn significantly affect the blood rheology.
The mechanisms of ND engulfment by macrophage were analyzed via alternatively blocking different possible pathways. ND was found non-cytotoxic to macrophages and can be engulfed by macrophages through the clathrin-mediated endocytosis pathway. Upon internalization, ND in cytoplasm is entrapped in lysosomes; it does not activate transcriptional factors nor induce macrophages to produce the proinflammatory
cytokines. ND effects on oxygenation and deoxygenation processes of whole RBC
and of hemoglobin solution are compared. It was shown that preliminary modification of ND
surface with blood plasma protein albumin significantly increases the biocompatibility of ND at its interaction with blood, including its effects on RBC functioning and on blood plasma
composition and properties, particularly, decreasing the uncontrollable adsorption of plasma
components. Finally, interaction with blood and ND biodistribution in vivo will also be
discussed.

Nanodiamond films exhibit many of the extreme properties of bulk diamond but in a wafer scale package over much larger areas and at significantly reduced cost. Nanodiamond film properties such as Young&’s Modulus, Coefficient of Friction and wear resistance are identical to those of single crystal diamond and in some cases enhanced by nano-crystallinity. Properties that involve carrier or phonon transport are obviously degraded by grain boundary scattering and thus carrier mobility and thermal conductivity are a function of grain size in nanodiamond films. Nanodiamond films have applications as diverse as a Micro-Electro-Mechanical Systems (MEMS), heat spreaders and electro-chemical electrodes.
Nanodiamond particles are fundamental low dimensional diamonds with extreme surface to volume fractions, as high as 400m2/g. This surface to volume fraction has a profound effect on the properties of these particles, with 20% of the carbon atoms residing at the surface. The reactivity of these particles differs substantially for bulk diamond and considerable effort is required to disperse them from their aggregated commercial source. Their applications are as diverse as the seeds for diamond film growth through drug delivery to single photon sources.
This talk will aim to review some of the technology and processes involved in utilising nanodiamond films and particles for real world applications.

Nanodiamond, a sp3 crystalline nanocarbon, has recently received increasing attentions due to its various potential applications, especially in composite and biomedicine fields. Here we will present our studies of engineering nanodiamond via different physical and chemical methods for some specific applications. The subsequently characterizations, including X-ray photon spectroscopy and transmission electron miscroscopy, as well as the advanced synchrotron radiation light source were employed to investigate the modified nanodiamond products. Some interesting results and sights were obtained, i.e. abnormal absorption behavior, unique optical and mechanical properties.

Many prospective applications of nanodiamonds (NDs), such as drug delivery or biolabeling, occur in water or physiological media. The characterization of electronic properties of NDs in aqueous solution is therefore fundamental for a better understanding of their behavior in physiologically relevant conditions. However, NDs characterization is generally performed on NDs deposited on a substrate because of the lack of experimental methods to measure electronic properties of NDs in water.
The use of soft X-ray absorption spectroscopy (XAS) and emission spectroscopy (XES) in liquid is particularly interesting for this purpose. Combination of tunable intense X-ray photon source of synchrotron with microjet technology has shown to be an efficient method to characterize electronic structure of solutes dispersed in water (1). In particular, we recently applied this technique to acetate molecule and demonstrated that the carboxylate groups of acetate could be selectively probed to investigate ion pairing with cations in solution (2). Similar experiments on NDs could help understanding drug binding mechanisms in solution for example.
In this presentation, first characterization of carboxylated detonation NDs in water by XAS and XES will be presented. Experiments were conducted at the BESSY II third-generation synchrotron facility using a liquid microjet. The carbon K-edge as well as the oxygen K-edge of NDs will be presented and compared to spectra obtained from NDs deposited on a substrate. Based on this comparison, interaction between NDs and water molecules in liquid will be discussed. This study highlights the potential of soft X-ray spectroscopy for characterization of the electronic structure of nanoparticles which can be probed directly in solution.
1. Lange, K. M. & Aziz, E. F. Electronic structure of ions and molecules in solution: a view from modern soft X-ray spectroscopies. Chem. Soc. Rev. 42, 6840-59 (2013).
2. Petit et al, Probing Ion-specific Effects on Aqueous Acetate Solutions: Ion Pairing versus Water Structure Modifications, submitted.

Our recent work in the measurements of and by carbon nanostructures, especially carbon nanotubes and graphene, provides a foundation upon which to build a vibrant nanodiamond program. NIST plans to harness the benefits of this unique, quantum mechanical system; nitrogen vacancy (NV) nanodiamond, to enable SI-traceable force, thermal and magnetic metrology. The luminescent NV impurity has been demonstrated as a magnetic and electrical fields and temperature sensor, and provides a possible vehicle for use in quantum information systems. In this work, we describe novel methods for manipulating nanoscale diamond particles leveraging the tip of an atomic force microscope (AFM). Ultimately we plan to attach the nanodiamond to the tip to sense surfaces. The resulting nanostructures enable a platform to thoroughly study the optical properties the isolated nanodiamonds. Both resonant Raman and fluorescence spectroscopy are used to establish the quality and location of the NV centers. Ultimate goals include the combination of mechanical and optical characterization for tip-enhanced Raman spectroscopy and torsional AFM measurements.

The purity of nanodiamond (ND) is of great importance for the characterization of the properties of ND. Unfortunately, there is a lack of the information on presence of elemental impurities in ND, which was connected for many years with the absence of the sensitive and robust methods for the analysis of this type of nanocarbon material.
Recently, a novel simple, rapid, sensitive and accurate method for the determination of metal impurities in detonation ND, based upon the direct aspiration of aqueous suspensions of nanodiamond into a sector field inductively coupled plasma mass spectrometer (ICP-MS) was developed. This method of direct analysis was capable of the quantification of more than 30 elements at concentration levels of 10-8 wt. %, with acceptable levels of precision and accuracy, from an aqueous suspension of just 0.1 mg mL-1 DND.
The further application of ICP-MS method to the analysis of more than 20 commercial samples allowed identification of possible sources for the contamination of various DND samples during their processing. The careful of reasons for the contamination and elimination of them caused a significant improvement in the existing technology of their purification. As a results the content of 28 most common elemental impurities in ND was dropped to the level of 0.05 mass %.
This work was supported by grants from the Australian Research Council to ACROSS (DP110102046) and CSL (LE0989539).

We have used Attenuated Total Reflectance Infra Red (ATR IR) spectroscopy to study changes to the surface vibrational spectra of nanodiamond (ND) particles while they are immersed in different solutions.
ATR IR works on the principle of total internal reflection, where incident IR radiation is directed through optics to a diamond prism, where it undergoes total internal reflection at the surface. However some of the IR radiation penetrates a region ca. 1 mu;m above the prism as an evanescent wave, where it can interact with an immobilised solid sample or a solution. If a solvated solid nanoparticle film is immobilised on the prism a vibrational spectrum of the nanoparticle material is obtained and as the IR does not have to pass through a substantial solvent layer absorption by the solvent is minimised. Indeed use of nanoparticulate materials, such as nanodiamond, allows for exquisite sensitivity towards surface processes, thanks to the high surface area.
We have monitored changes to the spectrum of solvated nanodiamond over time in water and can see changes in orientation and hydrogen bonding of surface water that take place over approximately a one hour time period as the film becomes increasingly solvated. There is some evidence also of hydrolysis of water on the surface of the nanodiamond and its reaction with the surface. Additionally we see evidence for reactions between surface functional groups. These observations are confirmed by performing the same experiment in deuterated water, but with some interesting differences. We have introduced both hydrophilic and hydrophobic molecules into the solution, where we can monitor the interaction of the molecules with the nanodiamond surface, primarly through monitoring disruption of hydrogen bonding at the nanodiamond surface and displacement of surface solvating water molecules. This fundamental study has relevance to many proposed applications of nanodiamond, where its interaction with solvents and dissolved species is of importance.

Nanodiamonds hold great potential for fluorescence microscopy and bioimaging applications. Aqueous nanodiamond solutions containing small size diamond nanocrystals have been observed to exhibit high scattering due to large index of refraction of nanodiamond. We are conducting studies to investigate spectroscopic properties of nanodiamonds of sizes ranging between 10 - 100 nm, suspended in solutions. In this work, we will present systematic studies conducted to determine the absorption, scattering and luminescent properties of various nanodiamond samples synthesized by different processing techniques for use in fluorescent labeling for bioimaging applications.

Our studies utilize photothermal spectroscopy to measure bulk absorption properties of nanodiamonds suspended in aqueous solutions. Photothermal spectroscopy gives us the advantage of independently measuring absorption properties of photoactive nanodiamonds with nitrogen vacancy (NV) centers in presence of high scattering. This method also allows us to calculate the quantum yield of scattering for different size nanodiamonds. Several different types of samples (synthesized by detonation and high pressure high temperature, type 1b) are used in the studies. Additionally, we will also present results showing room-temperature spectral fluorescence obtained for different nanodiamond samples using an instrument constructed by integrating a high light-throughput double-grating spectrophotometer with an inverted microscope.