Characteristics of silica-chitosan complex membrane and their relationships to the characteristics of growth and adhesiveness of L-929 cells cultured on the biomembrane

The relationships between the chemical and physical characteristics of a silica-chitosan complex membrane (SiCM) and the characteristics of growth and adhesion of fibroblast-like L-929 cells cultured on the surface of SiCM were investigated for development of a novel implant biomaterial for use as artificial skin. Silicon ethoxide was used to cross-link the chitosan complex membrane to enhance its oxygen permeability. The composition of the SiCM was stepwise controlled by adjustment of the mixing ratio between silica and chitosan, for silica contents of 20, 33, 43, and 50 wt%. The zeta potential of the SiCM varied negatively according to the silica content, from +20 mV for chitosan membrane (0%-SiCM) to -0.6 mV for 43%-SiCM. Similarly, the wet contact angle decreased from 68 degrees to 41 degrees according to the increase in the silica content up to 43%. However, significant increases in the wet contact angle and the zeta potential occurred upon further increase of the silica content to 50%. The adhesion and growth characteristics of L-929 cells on SiCM were found to be related to the surface properties of the SiCMs. The cell proliferation rate was higher on the 0, 20 and 50%-SiCMs than on a typical polystyrene culture dish. The strongest cell adhesion was obtained on 50%-SiCM among the complex membranes. Thus, the surface wet contact angle and the zeta potential of 50%-SiCM, which is highly permeable to oxygen, were found to be suitable for L-929 cell adhesion and growth, and therefore to promote tissue culture on the SiCM in vitro.