Dynamic Cellular Adhesion Mediated by Copolymeric Nanofilm Substrates

Amphiphilic block copolymers are finding increased potential in biological and medical research due to their innate alternating hydrophilic and hydrophobic blocks/segments that can be used to package therapeutics, or coat a broad array of biological interfaces. Some studies are already directed toward using these copolymers' ability to form micelles or vesicles to develop novel methods of drug delivery to prevent inflammation or pro-cancer activity. Our study, however, aims to investigate the more fundamental cell—block copolymer interaction for use in protective nanofilms to prevent biofouling of non-tissue-based implantable devices. Block copolymers could potentially fill the demand for biologically inert, highly functionalizable biomaterials desirable for this type of application. Two such polymers used in our study include polymethyloxazoline—polydimethylsiloxane—polymethyloxazoline (PMOXA—PDMS—PMOXA) triblock copolymer and polyethylene oxide-poly(methyl methacrylate) (PEO—PMMA) diblock copolymer. Each block copolymer possesses hydrophilic and hydrophobic blocks that enable it to mimic the cell lipid membrane. So far we have shown that triblock copolymer is capable of inhibiting the accumulation of murine macrophages onto glass substrates. Preliminary evidence has suggested that the triblock copolymer has anti-adsorptive and noninflammatory capabilities during short incubation periods (7 days) in vitro. While the diblock copolymer displays minimal anti-adsorptive activities, nanofilms comprising a mixture of the two copolymers were able to significantly reduce macrophage accumulation onto glass substrates. The disparate behavior of macrophages on the different materials may be due to specific inherent properties such as preference for hydrophobic versus hydrophilic surfaces and/or rough versus smooth nanotextures. Furthermore, the specific endgroups of the two polymers may exhibit varying capacities to resisting non-specific protein adsorption. Continued investigation outlining the physical and chemical properties desirable for an anti-adsorptive nanofilm coating will serve as a basis to design durable implant—tissue interfaces that can react to various external stimuli.