Cellular interactions on nano-structured polyelectrolyte multilayers

Cellular interactions onto the polymeric surfaces which prepared with polyelectrolytes by layer-by-layer process using H-bonding interactions were studied. Hydrogen-bonded multilayers containing polyacrylamide (PAAm) that assembled with weak polyelectrolytes, such as poly(acrylic acid) (PAA) or polyaspartic acid (PASA) were investigated for their surface–cell interactions. The assembled films were lightly crosslinked thermally in order to render them stable in a physiological environment. Both PAA/PAAm and PASA/PAAm multilayers were found to exhibit a high resistance to the adhesion (cytophobicity) of mammalian cells (epithelial cell and blood cell), even with only a few nanometer-thick coating. PASA is a biodegradable polymer; therefore, the unmodified form may not be stable as a surface coating. However, the well-blended PASA/PAAm multilayer films exhibit the cell-adhesion resistance property without a significant film deformation at least more than a week. More interestingly, one additional coating of polycationic layer rendered the cell-resistant surface into the cell-adhesive surface. Using the reactive carboxylic acid groups remaining after the multilayer assembly, antibacterial nanoparticles were also synthesized.