Chapter 14 - Optically Based Sol-Gel Biosensor Materials

Abstract

This chapter describes the fundamentals of sol-gel encapsulation and the history of these materials along with a review of the effects of sol-gel encapsulation on biomolecules. The sol-gel process is a chemical technique for synthesizing a silicate matrix around a biomolecule that can function as the recognition and signaling element for a sensor. Within the past decade, biologically doped sol-gel glasses have surfaced as having great potential in optical biosensor applications. The materials are transparent in the UV and visible spectra allowing for the transmission of optical signals. The glass is porous such that small analyte molecules can diffuse through the matrix and reach the large biomolecule that is physically trapped. Biological molecules including heme proteins, enzymes, and antibodies can remain active within the porous sol-gel glass. The flexibility of the method has allowed the encapsulation of a wide range of biomolecules and cells, resulting in sensor materials able to detect small molecules in both gases and in liquids. The chapter concludes with a discussion of the advantages and limitations of sol-gel optical biosensors.