Encapsulation and activity of molecules in sol-gel materials

The primary goal of the work in this dissertation is to explore the properties of molecules encapsulated silicate made by the sol-gel method. The sol-gel process is a chemical synthesis technique for preparing oxide gels, glasses, and ceramics at low temperatures. The physical encapsulation and entrapment of enzymes, proteins, and other macromolecules in the pores of the sol-gel protects the structure, prevents unfolding, and stabilizes the molecule. The sol-gel can be used in applications such as in biosensors, mesostructured energy transfer materials, and robust materials in organic solvents.; The main focus of this dissertation is the encapsulation and stabilization of biomolecules in the sol-gel matrix. We have investigated the effects of confined space, structural changes of the pore walls, and enzyme silica interaction. Creatine kinase, an important enzyme in cellular energetics, is encapsulated and stabilized in the pores of optically transparent sol-gel matrices. The activity of the monoliths is measured as a function of long-term storage and at elevated temperatures, and compared to solution. Surprisingly, a four-fold increase in activity is observed after short exposures to elevated temperatures. The stabilization of the enzyme in the sol-gel matrix is interpreted in terms of electrostatic interactions between the enzyme and the sol-gel matrix, and the conformational changes of the enzyme and the pores upon heating. Another enzyme, which also exhibits stabilization, is alanine transferase, an important enzyme in amino acid metabolism.; Utilizing the stabilization of enzymes in sol-gel matrices, other potential applications are exploited. A biosensor is developed by encapsulating creatine kinase, along with the reagents for the reaction on the tip of a fiber optic to detect creatine phosphate. Another study involves the encapsulated creatine kinase that is milled into a fine slurry for diagnostic instrumentation. Biomolecules can also be deliberately placed in mesostructured thin-films templated by surfactants to produce energy transfer between the biomolecule and a dye.; The results from this dissertation show that sol-gel matrices are practical hosts for biomolecules. Potential applications utilizing the stabilization of molecules in this material are also explored.