A Biomimetic Process for Enzyme Immobilization within Polycation-Templated Silica

A simple and scalable procedure for enzyme entrapment, termed silica co-precipitation, has been developed. The process was initially inspired by the ability of diatoms and other marine organisms to rapidly mineralize silica through the action of polycationic peptides termed silaffins. A mixture of an enzyme and a polycationic polymer such as polyethylenimine (PEI) is added to a phosphate-buffered silicate solution (PBSi) and results in the rapid formation of a colloidal coprecipitate consisting of the enzyme, the polycation within a hydrated, amorphous silica matrix. The process has been applied to a series of enzymes and the properties of the resulting composites characterized.