Entrapment of enzymes in nanoporous sol-gels

The prerequisite for many successful enzyme-based biotechnologies is the preparation of highly stable and active biocatalysts, which can be achieved effectively by immobilization. This chapter introduces the immobilization of enzymes by entrapment in nanoporous silica particles made in a sol-gel process. These easily tailorable materials have been proven very beneficial for a broad variety of applications of biocatalysts. Besides the spatial confinement in silica sol-gels, another advantage is given by the easy possibility of fine-tuning the physicochemical properties of the matrix itself to provide the ideal environment for the reaction and the biocatalyst. Preparation details are demonstrated using the process of immobilizing a lipase in a sol-gel matrix, which is chemically modified by using methyl-, ethyl-, propyl-, and i-butyltrimethoxysilane. The transesterification of canola oil with methanol is used as a model reaction.

Bioencapsulation within synthetic polymers (Part 1): sol-gel encapsulated biologicals

Since its inception a decade ago, sol-gel encapsulation has opened up an intriguing new way to immobilize biological materials. An array of substances, including catalytic antibodies, DNA, RNA, antigens, live bacterial, fungal, plant and animal cells and whole protozoa, have been encapsulated in silica, metal-oxide, organosiloxane and hybrid sol-gel polymers. The advantages of these 'living ceramics' might give them applications as optical and electrochemical sensors, diagnostic devices, catalysts, and even bioartificial organs. With rapid advances in sol-gel precursors, nanoengineered polymers, encapsulation protocols and fabrication methods, this technology promises to revolutionize bioimmobilization.