Simulation of the formation of densely crosslinked polymeric networks for use as biomaterials
A method simulating the formation of densely crosslinked polymeric networks was developed that incorporates both intramolecular as well as intermolecular interactions and the subsequent effects they have on the end network structure. The all-atom nature of the model allows for the simulation of network formation in a variety of conditions including differing solvent qualities and presence of inert species, as well as non-local effects such as polymerization in the presence of a template molecule. Our all-atom kinetic gelation technique utilized an off-lattice approach that tracked the position and interaction of all atoms throughout the simulation. This model was subsequently used to study the creation of polymeric networks capable of recognizing and binding one specific molecule out of a host of competing species. Namely, our all-atom kinetic gelation model was used to study the formation of a material capable of recognizing the important biological molecule, D-glucose. One method for the formation of a glucose-responsive material is the molecular imprinting technique, whereby the target molecule is included in the polymerization and acts as a template. In the simulation of this process, electronic structure theory was first used to determine the relevant properties of the monomers of interest. Parameters for a CHARMM-style force field were then derived from these results. Finally, simulation of the imprinted network formation was done using the all-atom kinetic gelation simulation, which highlighted the interactions central to recognition. These results were then verified experimentally. The imprinting method was then modified to allow for the formation of materials capable of binding large molecules such as proteins. Microparticles capable of binding significant amounts of the protein bovine serum albumin (BSA) were synthesized using this new surface imprinting technique. Densely crosslinked microparticles of a mean diameter of 1.6 μm were formed with a controlled surface chemistry amenable to molecular recognition. Studies of equilibrium protein binding showed significant amounts (18% by weight) of BSA were adsorbed with high affinity while other model proteins were rejected. Possible applications for such materials include bioseparations media, antibody analogues, sensing elements, and recognitive elements for MEMS devices.
Thomson, Purdue University.
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