Stable sol-gel microstructured and microfluidic networks for protein patterning

We demonstrate the formation of micropatterned sol-gel structures containin g active proteins by patterning with polydimethylsiloxane (PDMS) microchann els. To transport sol solution efficiently into the hydrophobic PDMS microc hannels, a hydrophilic-hydrophobic block copolymer was used to impart hydro philicity to the PDMS microchannels. Poor adhesion of the micropatterned ge l structure onto glass slides was improved by treating the glass surface wi th a polymeric substrate. To minimize cracks in the gel microstructure, hyb rid matrices of interpenetrating organic and inorganic networks were prepar ed containing the reactive organic moieties polyvinylalcohol or polyvinylpy rrolidone. Retention of biochemical activity within the micropatterned gel was demonstrated by performing immunobinding assays with immobilized immuno globulin G (IgG) antibody. The potential application of microfluidics techn ology to immobilized-enzyme biocatalysis was demonstrated using PDMS-patter ned microchannels filled with trypsin-containing sol-gels. This work provid es a foundation for the microfabrication of functional protein chips using sol-gel processes. (C) 2001 John Wiley & Sons, Inc.