Symposium Organizers
Kevin Plaxco University of California-Santa Barbara
Ted Tarasow Tethys Bioscience
Magnus Berggren Linkoping
Ananth Dodabalapur University of Texas-Austin
BB3: Sensor Materials and Technology
Session Chairs
Magnus Berggren
Luisa Torsi
Wednesday PM, March 26, 2008
Room 3010 (Moscone West)
3:00 PM - **BB3.1
Responsive Nanoporous Colloidal Materials with Controlled Molecular Transport.
Ilya Zharov 1
1 Chemistry, University of Utah, Salt Lake City, Utah, United States
Show Abstract3:30 PM - BB3.2
Electrostatic Detection of DNA.
Khalid Salaita 1 2 , Nathan Clack 3 , Jay Groves 1 2 3
1 Chemistry, University of California, Berkeley, Berkeley, California, United States, 2 Physical Biosciences, Lawrence Berkeley National Laboratories , Berkeley, California, United States, 3 Biophysics Graduate Group, University of California, Berkeley, Berkeley, California, United States
Show AbstractWe describe a sensitive and label-free electrostatic readout of DNA or RNA hybridization in a microarray format. The electrostatic properties of the microarray are measured using the positions and motions of charged microspheres randomly dispersed over the surface. This approach enables non-destructive electrostatic imaging over centimeter length-scales, which is four orders of magnitude larger than that practically achievable with electric force microscopy. Changes in surface charge density as a result of specific DNA hybridization can be detected and quantified with 50 pM sensitivity, single base-pair mismatch selectivity, and in the presence of a complex background. Moreover, no more than a magnifying glass is needed to read out the microarray, potentially enabling the broad application of inexpensive genome-scale assays for point-of-care applications.
3:45 PM - BB3.3
Electrochemical In-Situ Micropatterning of Cells and Conducting Polymers.
Matsuhiko Nishizawa 1 , Takahiro Kitazume 1 , Takashi Kamiya 1 , Hirokazu Kaji 1
1 , Tohoku Univ., Sendai Japan
Show AbstractWe will report techniques to make biocompatible, conductive micropatterns on insulating substrates such as glass or polyimide by controlling the lateral growth rate of polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) upon the electropolymerization at microelectrodes formed on the substrates. We found that pre-modification of the substrate surface with self-assembled monolayer (SAM) of alkylsilane or heparin induces anisotropic (more than 10 times faster) lateral growth of conducting polymers along the substrate surface [1, 2]. This controllable anisotropic growth of conducting polymers has enabled the following studies, including the formation of hybrid micropatterns of cells and conducting polymers:1) The PPy film laterally grown around the electrode anchors the whole film and significantly enhances film adhesion. The anchored PPy film was stable even during a long-term cultivation, and serves as an electrode for reproducible, noninvasive, external stimulation of a cultured excitatory cells. For example, the myocytes on the microelectrode substrate were electrically conjugated to form a sheet, and showed synchronized beating upon stimulation (Fig. 1). The threshold charge for effective stimulation of an 0.8 cm2 sheet of myocytes was systematically evaluated to be around 0.2 µC.2) The micropatterns with SAM of alkylsilane or heparin lead to a micropatterns of PPy upon the polymerization (Fig. 2). Importantly, the electropolymerization of PPy can be conducted even during cell cultivation without significant damage to the existing cells (data will be shown in presentation). Therefore, in-situ electrical wiring to cultured cells would be possible (Fig. 3).3) The surface modification with heparin can be easily detached by a non-invasive electrochemical biolithography, and thus we can draw micropatterns of PPy by using a needle-type microelectrode as a “pen” (Fig. 4). Since we have achieved the in-situ cellular micropatterning by this electrochemical biolithography (Fig. 5) [3, 4], we can expect the formation of hybrid micropatterns of conducting polymer and living cells.-----------------------References:Micropatterning of Conducting Polymers:[1] M. Nishizawa, H. Nozaki, H. Kaji, T. Kitazume, N. Kobayashi, T. Ishibashi and T. AbeBiomaterials, (2007) 28, 1480.[2] M. Nishizawa, T. Kamiya, H. Nozaki and H. KajiLangmuir, (2007) 23, 8304.Cellular Micropatterning:[3] H. Kaji, K. Tsukidate, T. Matsue and M. NishizawaJ. Am. Chem. Soc., (2004) 126, 15026.[4] H. Kaji, T. Kawashima, M. NishizawaLangmuir, (2006) 22, 10784.
4:00 PM - BB3: Materials
BREAK
4:30 PM - **BB3.4
Signal Transduction Using Nanobio Materials: Application to Biological Sensing.
Basil Swanson 1 , Aaron Anderson 1 , Andrew Beveridge 2 , Andrew Dattelbaum 3 , Karen Grace 4 , Wynn Grace 1 , Jennifer Martinez 3 , Harshini Mukundan 1 , Jurgen Schmidt 2
1 Chemistry, Los Alamos National Laboratory, Los Alamos, New Mexico, United States, 2 Bioscience Division, Los Alamos National laboratory, Los Alamos, New Mexico, United States, 3 Center for Integrated Nanotechnology, Los Alamos National laboratory, Los Alamos, New Mexico, United States, 4 International Space and Response Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States
Show Abstract5:00 PM - BB3.5
Spatially and Temporally Controlled Release of Biomolecules using an Organic Electronic Ion Pump.
Klas Tybrandt 1 3 , Karin Larsson 2 3 , Joakim Isaksson 1 3 , Daniel Simon 1 3 , Sindhulakshmi Kurup 2 3 , Peter Kjäll 2 3 , Edwin Jager 1 3 , Agneta Richter-Dahlfors 2 3 , Magnus Berggren 1 3
1 Department of Science and Technology, Linköping University, Norrköping Sweden, 3 , Strategic Research Center for Organic Bioelectronics (OBOE), Norrköping Sweden, 2 Department of Neuroscience, Karolinska Institutet, Stockholm Sweden
Show AbstractThe use of conducting polymers in biological applications has received significant attention lately. Desirable properties such as electronic and ionic conductivity, flexibility and biocompatibility make some polymers well suited for use in biological systems. We demonstrate an electrophoretic organic ion pump for controlled release of biologically relevant molecules. A film of the polymer poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulphonate) (PEDOT:PSS), on a flexible and transparent plastic substrate, is used both as the electronic and ionic conductor. By applying a voltage across the device, ions are transported from one container to another through the polymer film. The pumping rate is controlled by the applied voltage and the amount of pumped ions agrees with the integrated electrical current. The ion pump has already been successfully used to electronically control Ca2+ signalling in neuronal cells. Here we report on a novel bioelectronic device architecture, which enables both spatial and temporal control of ion release. The high degree of control makes it promising for even more advanced biological studies.
5:15 PM - BB3.6
Protein Detection Using Dual Recognition Aptamers and Continuous Magnetic-Activated Separation.
Aren Gerdon 1 , H. Soh 1
1 , University of California, Santa Barbara, Santa Barbara, California, United States
Show Abstract5:30 PM - BB3.7
New Platform of Artificial Nanochannels for Detecting DNA Translocation.
Zhu Chen 1 , Yingbing Jiang 2 , David Adams 2 , Carter Hodges 2 , Michael Vasile 2 , Nanguo Liu 3 , C. Brinker 2 1
1 , University of New Mexico, Albuquerque, New Mexico, United States, 2 , Sandia National Laboratories, Albuquerque, New Mexico, United States, 3 , Dow Corning Corporation, Midland, Michigan, United States
Show Abstract
Symposium Organizers
Kevin Plaxco University of California-Santa Barbara
Ted Tarasow Tethys Bioscience
Magnus Berggren Linkoping
Ananth Dodabalapur University of Texas-Austin
BB5: Devices and Circuits to Sense and Actuate Systems in Biology
Session Chairs
Ananth Dodabalapur
David Martin
Thursday PM, March 27, 2008
Room 3010 (Moscone West)
2:30 PM - **BB5.1
Conducting Polymer Transistors for Sensor Applications.
George Malliaras 1
1 Materials Science, Cornell University, Ithaca, New York, United States
Show AbstractThe application of organic semiconductor devices to chemical and biological sensors seems to be a great fit. Organics offer facile processing, which can result into low fabrication costs - a requirement for sensor proliferation. Chemical synthesis can be used to tune their electronic properties and to attach chemical and biological receptor sites, leading to high sensitivity and specificity. Low-end performance, which prohibits organics semiconductors from competing with silicon in some technology areas, is not a limitation for sensors. Also, lifetime issues which usually plague organics, are not relevant for disposable sensors. A promising approach towards organic-based sensors involves the use of conducting polymer transistors. These devices act as efficient ion-to-electron converters, therefore they help interface the worlds of biology and electronics. I will examine the mechanism of operation of conducting polymer transistor-based sensors and discuss several different approaches for introducing specificity towards target analytes.
3:00 PM - **BB5.2
Nanoscale Chracterization of Metalized Microtubules.
Ghassan Jabbour 1
1 , Flexible Display Center at Arizona State University, Tempe, Arizona, United States
Show AbstractWe will present our work in the area of metalized microtubules based on organic materials. Complete morphology studies as well as electrical characterization using conductive AFM will be presented. Potential applications in nureal networks and nanoelectronics will be discussed.
3:30 PM - BB5.3
Electrically Modulated Conducting Polymer Ion Pumps for Precision Bio-electronics.
Daniel Simon 1 4 , David Nilsson 2 4 , Klas Tybrandt 1 4 , Edwin Jager 1 4 , Sindhulakshmi Kurup 3 4 , Karin Larsson 3 4 , Joakim Isaksson 1 4 , Peter Kjäll 3 4 , Agneta Richter-Dahlfors 3 4 , Magnus Berggren 1 4
1 Dept of Science and Technology (ITN), Linköping University, Norrköping Sweden, 4 , Strategic Research Center for Organic Bioelectronics (OBOE), Stockholm Sweden, 2 , Acreo AB, Norrköping Sweden, 3 Dept of Neuroscience, Karolinksa Institute, Stockholm Sweden
Show Abstract3:45 PM - BB5.4
Active, Non-Flow Chemical Delivery.
Jules VanDersarl 1 , Nicholas Melosh 1
1 Materials Science and Engineering, Stanford University, Stanford, California, United States
Show Abstract4:00 PM - BB5: Devices
Break
4:15 PM - **BB5.5
Enhanced Sensing Capabilities of Organic Thin-film Transistors.
Luisa Torsi 1 , Francesco Marinelli 1 , Eliana Ieva 1 , Daniela Angione 1 , Francesco Palmisano 1 , Pier Giorgio Zambonin 1
1 Chemistry, Università degli Studi di Bari, Bari Italy
Show Abstract4:45 PM - BB5.6
Liquid Field Effect Transistors for Signal Transduction at the Biology-Electronics Interface.
Andrew Steckl 1 , Duk Kim 1 , Srikoundinya Punnamaraju 1
1 Nanoelectronics Laboratory, University of Cincinnati, Cincinnati, Ohio, United States
Show AbstractWe have recently demonstrated transistor action in the liquid state. Control of current flow in a liquid-state field effect transistor (LiquiFET) was achieved through the electrowetting (EW) effect. The LiquiFET current-voltage characteristics exhibit many similarities (and some differences) to those of conventional semiconductor MOSFETs. We are currently investigating the interaction of LiquiFETs with biochemical species in fluidic systems. LiquiFETs have great potential for bioapplications - they can directly detect, manipulate and analyse liquids and they can be immersed in liquids. Control of current flow in the LiquiFET was achieved by EW between competitive insulating/conducting fluids. Applying a voltage across the solid-liquid interface can change the shape of a water droplet placed on a hydrophobic surface. The LiquiFET operates by the competitive electrowetting effect between an electrolyte (typically saline water solution) and a non-conducting fluid (such as non-polar oils), placed on the surface under the control of the gate voltage. With no gate voltage to the electrode, the oil layer settles itself in between the water layer and the hydrophobic surface because of the surface tension between the two liquids. Under this condition, the oil prevents any current from flowing between source and drain and the transistor is in the OFF state. When gate voltage is applied to the water droplet, electrowetting occurs, which means that the water droplet pushes the oil layer away and provides a conducting path between the source and drain electrodes. At this point the LiquiFET switches ON. Moreover, the LiquiFET drain current increases with the gate voltage, as in a conventional FET, so the device displays the two fundamental actions of a transistor: switching and gain.For our proof-of-concept LiquiFETs, ON/OFF current ratios > 10,000:1 were measured. Using the LiquiFET transconductance values and the approximate channel capacitance, we calculate an effective channel mobility of ~1 cm2/V-s. This indicates that charge transport in the LiquiFET is predominantly electronic, as ionic mobility is much lower (10-4 - 10-3 cm2/V-s).LiquiFETs can be customized or modified in real time by simply inserting a different fluid. Therefore, LiquiFETs could represent the ultimate “just-in-time” device family. Furthermore, this customization will not require a special fabrication factory or sophisticated equipment. Indeed, it will be possible to customize the LiquiFET under very basic working conditions and at very low cost. A second application is in the integration of LiquiFETs with microfluidic devices. In this case the LiquiFET can provide real time continuous electronic read-out describing the fluids flowing through channel. Finally, the LiquiFET can be embedded into a biological medium (in-vitro or in-vivo) where it can provide information on the nature and properties of the organisms present in the liquid.
5:00 PM - BB5.7
Towards Passive Microfluidic Logic Devices.
Tarun Malik 1 , Nicholas Fang 1
1 , University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
Show Abstract5:15 PM - BB5.8
Arrayed Microfluidic Cell Traps for the Study of Cell Signaling.
Surendra Ravula 1 , Conrad James 1 , Matt Moorman 1 , Bryan Carson 1 , Jeff Lucero 1 , Igal Brener 1
1 Applied Photonic Microsystems, Sandia National Labs, Albuquerque, New Mexico, United States
Show Abstract5:30 PM - BB5.9
Isoelectric Focusing and Separation of Proteins by pH and Potential Gradient in a Nanofluidic Field Effect Transistor Device.
Youn-Jin Oh 1 , Danny Bottenus 2 , Cornelius Ivory 2 , Sang Han 1
1 Chemical & Nuclear Engineering, University of New Mexico, Albuquerque, New Mexico, United States, 2 Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington, United States
Show AbstractWe have fabricated Si multiple internal reflection infrared waveguides embedded with a parallel array of nanofluidic channels (100 nm W ×500 nm D) and studied field-effect-transistor (FET) flow control and separation of proteins, using scanning laser confocal fluorescence microscopy (SL-CFM) and multiple internal reflection Fourier transform infrared spectroscopy (MIR-FTIRS). For fluidic FET control, a DC potential is applied to a highly doped gate region in the mid-section of the channels, while an electroosmotic flow is induced by a longitudinal electric field along the nanochannels. The gate potential controls the surface charge on SiO2 channel walls and therefore the ζ-potential. Depending on the polarity and magnitude, the gate potential can accelerate, decelerate, or reverse the flow of proteins. We also monitor a pH shift in the nanochannels according to the surface charge modulation and longitudinal electrical field, using Fluorescein as a pH indicator. Our MIR-FTIR analysis shows that Fluorescein dye molecules are hydrogenated and dehydrogenated in response to the gate bias and subsequent pH shift. Based on monitoring pH changes, we demonstrate that the pH shift causes abnormal flow characteristics during the FET flow control. We conduct isoelectric focusing and separation of proteins with different isoelectric points (pIs) by generating a pH gradient along the nanochannels. A longitudinal pH gradient is induced using controlled water electrolysis under longitudinal electrical field and applying different potentials to multiple gates to differentially control the surface charge on the SiO2 channel walls. In this presentation, the effects of protein’s isoelectric point and net charge on separation and focusing by the pH gradient will be further discussed in terms of transverse electromigration and electroosmosis flow in nanofluidic channels.