KINETIC DOPING OF SILICA SOL-GEL THIN FILMS AND APPLICATION AS BIOSENSORS

Abstract

Easy to use and easy to produce biosensors would have a huge range of applications. To reach this goal many see the incorporation of a protein into a sol-gel network as one of the most viable options. The current most prevalent technique of pre-doping presents inherent limits on the concentration possible for the resulting thin film. In this study we demonstrate a new process utilizing the newly developed kinetic doping method to load silica sol-gel thin films with cytochrome C (CytC) and horseradish peroxidase (HRP). Both enzymes are shown to successfully load and have a concentration increase over their original loading solution by factors of 1300X and 2600X, respectively. Furthermore, each enzyme once loaded retained the ability to act as a catalyst for the detection of hydrogen peroxide. A new methodology for adapting the Bradford assay to determining the actual amount of accessible enzyme loaded is created and utilized. Ultimately the CytC- and HRP-loaded thin films were found to have enzyme concentrations of 11±1 mM and 6.0±0.4 mM, respectively, a 6X increase in concentration over a sample made via existing post-doping techniques under the same conditions.