Fabrication of permeable separator as a nano-porous scaffold for bio-reactor

In this study, nano-porous membrane of silicate hydrogel was developed as a separator wall of nanometer-sized bioreactor chambers. Thin silicate polymer membrane was fabricated on a silicon support structure by spin coat technique. Monomer concentration and pH of silicate reaction mixture was investigated to obtain appropriate porosity and mechanical strength of the membrane. The silicate gel membrane can be used as a semi-permeable membrane that controls the diffusion rate of substrate molecules. It also can be employed as a matrix for enzyme immobilization. Chemical stability and established surface modification techniques of silicate polymer are suitable for protein immobilization material. Silicate hydro-gel is, however, very fragile and it's use as an thin wall of a bioreactor separator is difficult. To reinforce the silicate membranew, it was spin coated on a silicon support structure with micrometer sized through holes, which was fabricated by anisotropic wet etching process. The immobilization density of enzyme molecules on the silicate gels was also investigated with various polymerization conditions. Results shows the enhancement of immobilization density by the factor of c.a. 20.