Bertrand Czarny1,Wen Jie Melvin Liew1,Abdullah Alkaff1,Atul Parikh2,3,Subramanian Venkatraman4,5
Nanyang Technological University, NTU1,University of California, Davis2,Nanyang Technological University3,National University of Singapore4,University of California, San Diego5
Bertrand Czarny1,Wen Jie Melvin Liew1,Abdullah Alkaff1,Atul Parikh2,3,Subramanian Venkatraman4,5
Nanyang Technological University, NTU1,University of California, Davis2,Nanyang Technological University3,National University of Singapore4,University of California, San Diego5
High initial burst release of biomolecules is just one of the many challenges faced by lipid based nanoparticulate formulations, even though it is widely used for drug encapsulation and delivery studies. One of the emerging potential strategies is the use of nanolipogels (NLG) to encapsulate biomolecules, which can suppress the initial burst release. This gives a level of control and sustain to the release of hydrophilic drugs. However, current works are short on characterisation of the release mechanistic. Therefore, varying molecular weight of Poly (ethylene glycol) Diacrylate (PEGDA) were used for the fabrication of PEGDA NLG, to study the mechanism for release of Dextran-Fluorescein Isothiocyanate (DFITC). Fluorescence Recovery after Photobleaching (FRAP), were performed on cell derived microlipogels (MLG), a novel system developed as a solution to limitations of FRAP with NLG. Results from the studies has shown that the NLGs’ mesh sizes are controllable via the use of different Mw of PEGDA, where a lower Mw used resulted in a smaller mesh size of the nanogel core, by having a higher crosslinking density. This in turn gave higher suppression of the initial burst release of DFITC, up to a 10-fold difference. FRAP results then gave further validation by showing that the smaller mesh size restricted the diffusion of DFITC, consequential of a lower mobile fraction. These gave clear insight into the possibility of controlling the encapsulation and release of biomolecules, by targeting the fabrication of nanogel core. From this, Chitosan Methacrylate (CMA) NLGs was then studied to expand into other ways in manipulating the nanogel core for greater control, such as a differently charged core. Results was shown that CMA NLGs are also able to suppress the initial burst release of DFITC and it can be controlled by using a different concentration of CMA. This increases the possible strategies for consideration during the design of NLG systems and especially CMA NLGs opens up the possibility of encapsulation of negatively charge biomolecules, such as siRNA. As the NLG system involves two critical components, namely the nanogel core and the bilayer coating, the membrane properties are essential for the designing of NLGs. Herein, cell membrane coating for NLG was studied, with the development of a novel Chitosan Methacrylate-Tripolyphosphate (CMATPP) nanoparticle systems, which allows for the co-extrusion with cell membrane vesicles. The coating of CMATPP nanoparticles can possibly confer the membrane properties, such as prolonged <i>in-vivo</i> circulation and improved cellular uptake, to CMATPP nanoparticles. Coating was validated through flow cytometry with characteristic membrane proteins of cell derived nanovesicles (CDN), namely CD9, CD81, TSG101, or with RBC membrane vesicles, CD47. RBC CMATPP NLGs were also shown that it can further suppress the initial burst release and sustained release compared to Liposome CMATPP NLGs. All in all, it was shown that cell mimicking NLG system was able to provide a controlled release of hydrophilic biomolecule, and the release mechanism was studied and characterized using FRAP. Relationships with changes to the nanogel core as well as membrane coatings were also explored and proven to be viable and plausible expansions to other membrane origins were discovered. This study has provided a guide on the design of NLGs for a multitude of needs with regards to encapsulation and delivery, as well as for future <i>in vivo</i> performance