AEROSOL-GENERATED SOL-GEL-DERIVED THIN-FILMS AS BIOSENSING PLATFORMS

We have incorporated an antibody into a sol-gel-derived thin film comp osite and demonstrated that it retains affinity for its hapten. An ine xpensive apparatus to produce and deposit, aerosol-generated sol-gel-d erived thin films was also developed. The antibody antifluorescein (AF ) was entrapped between two sol-gel thin films (0.62+/-0.05 mu m) in a sandwich architecture. The fluorescent hapten 5-(-and 6-)-carboxy-4', 5'-dimethylfluorescein (Me(2)F) was used to determine the accessibilit y and viability of the entrapped AE Results demonstrate that a populat ion of the entrapped antibodies recognizes and binds Me(2)F for up to 13 weeks when stored in pH 8 phosphate buffer at 4 degrees C. An intri guing result is that the response times of these AF-doped thin films a ctually improve as a function of storage time. We explain this observa tion in terms of decreased viability of AF molecules sequestered betwe en the upper and lower films of the sandwich. Partial regeneration (40 -50%) of the biosensor was obtained using a mild chaotropic reagent (N aCl) and the AF-doped films could be reset/regenerated up to six times .