In an ideal situation, tese properties are tunable independently such that optimal materials can be designed with the aim of achieving a cellular response. Pactically, mchanical rigidity and bioactivity are two properties that are hard to de-couple. Fr instance, eamples from nanofilm biomaterials created through the LbL method controls rigidity via chemically cross-linking the network of polymers after assembly, wile conference of bioactivity is done via surface adsorbed or film-embedded bio-molecules. Wen film bio-activation is preceded by cross-linking, te embedded bio-molecules could be rendered inaccessible to the cells in contact with, wereas when bio-activation is followed by cross-linking, bo-molecular loadings is limited at the surface of the film (Chow & Cheng 35).
Tus, fr the current approach to making polymer nanofilm coatings, boactivity and mechanical rigidity of the coating are strongly and usually inversely coupled. Tus, i was important to develop an approach to nanofilm coatings with bioactivity and mechanical rigidity that as tunable independently. Oe of the strategies to this was surface cross-linking, i which formation of cross-links was confined to the polymer film’s surface region not to interfere with species that are bioactive in the interior of the film (Yasuda 129).
Nno-particle templating was another strategy used, hre, te nanofilm was created alongside spherical latex nano-particles with cross-linking chemically, t improve rigidity of the film and imbue it with porous morphology, wile removing nano-particles through dissolution. I this case, te idea revolved around the creation of a polymer nanofilm by hardening the polymer portion using standard methods of cross-linking followed by filling pore spaces with bioactive species (Johal 55). Bth of these activities done extents that could be controlled independently.
I using each of these strategies, tere were key questions regarding how much the film would be penetrated by various macromolecular particles and species. Uing the cross-linking method, te polymer, i bound to cross-linking agents so that it adsorbs to the film but does not penetrate it, alowing for the formation of cross-links with polymers that were already adsorbed to the surface of the film (Yang et al. I this case, te most essential question was whether the formation of cross-links before penetration the polymer. ..
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