(537f) Porous Nanofilm Biomaterials: Biomolecular Adsorption and Cellular Adhesion
Hydrogel-like biomaterials are often too soft to support robust cell adhesion, yet methods to increase mechanical rigidity (e.g. covalent cross-linking of the gel matrix) can compromise bioactivity by suppressing the accessibility / activity of embedded biomolecules. Nanoparticle templating is reported here as a strategy toward porous, layer-by-layer assembled, thin (ca. 100 nm) polyelectrolyte films i) of sufficient mechanical rigidity to promote initial cell adhesion, and ii) exhibiting significant adsorption of bioactive species within the pore space. Latex nanoparticles are incorporated during layer-by-layer assembly, and following EDC-NHS cross-linking of the polyelectrolyte film, are removed via exposure to tetrahydrofuran (THF). THF exposure results in only a partial reduction in film thickness (as observed by ellipsometry), suggesting the presence of internal pore space. The attachment, spreading, and metabolic activity of pre-osteoblastic MC3T3-E1 cells cultured on templated, cross-linked films are statistically similar to those on non-templated films, and much greater than those on non-cross-linked films. Laser scanning confocal microscopy and quartz crystal microgravimetry indicate a high capacity for bioactive species adsorption (ca. 10% of film mass) wthin nanoparticle templated films. Porous nanofilm biomaterials, formed via layer-by-layer assembly with nanoparticle templating, promote robust cell adhesion and exhibit high bioactive species loading – and thus appear to be excellent candidates for cell-contacting applications.