The Effects of Doping on the Behavior of Sol-Gel Entrapped Proteins

Abstract

<p> Research in the field of sol-gel derived materials has evolved dramatically over the past forty years. The developments in the past decade, in the field of bioanalytical chemistry, have revolutionized this field. Early research, as well as that done by our group, has confirmed that the commonly used alkoxysilane precursors (tetraethylorthosilicate - TEOS or tetramethylorthosilicate - TMOS) are not ideal for entrapment of biomolecules. They produce materials that are brittle, often undergo cracking due to hydration stresses and in some cases, can block the accessibility of the analyte to the entrapped biomolecules. My research project therefore focuses on the development of new sol-gel processing methods through the use of an additive-glycerol, which will produce new "second generation" glasses. I have focused on obtaining a basic understanding of glycerol-doped sol-gel derived materials and the effect they have on the entrapped biomolecules. Glycerol-doped sol-gel materials display larger pore size, decreased shrinkage and cracking as compared to the TEOS-based materials. Biocatalysts entrapped in glycerol-doped materials showed significantly smaller decreases in activity over a period of one month relative to enzyme entrapped in TEOS. Also, to gain further insight into the effects of glycerol doping on the properties of entrapped proteins, both steady-state and time-resolved fluorescence of Trp 214 was used to examine the conformation, dynamics, accessibility, thermal/chemical stability and the degree of ligand binding of human serum albumin (HSA) in solution and after entrapment of the protein in glycerol-doped TEOS-based materials.</p>