Functional Aerogels

Aerogels, the world`s lightest solids, possess extraordinary traits. They have immense surface area, high porosity and ultra-low heat conductivity. These traits made aerogels favorable in various fields, from aerospace to building insulation. Nonetheless, the use of aerogels for the entrapment of biomolecules remains relatively undeveloped. In this work I present progress in this field, demonstrating entrapment of enzymes in aerogel, controlled release of a microbicidal agent and synthesis of magnetic aerogel, suitable for biomolecule entrapment. First, I present the successful entrapment of acid phosphatase, horseradish peroxides, glucose oxidase and protease in silica aerogel. Not only do the enzymes retain their catalytic activity, but they also exceed the activity of a similar entrapment in xerogel. This illustrates the advantage of enzyme entrapment in aerogel, where the highly porous structure enables diffusion of the substrates in and out of the scaffold. Second, the adjustable, controlled release of chlorhexidine digluconate salts is shown. Chlorhexidine digluconate, a common disinfectant, was entrapped in silica aerogel and its release pattern was controlled, by modifying the hydrophobicity of the matrix. High loading was achievable, owing to the aerogels high surface area. Finally, the only oxide used for encapsulation of biomolecules currently is silica. I aim to expand this ability to other oxides such as iron and aluminum oxides. Recently, we have managed to synthesize a pure magnetic, iron oxide aerogel. This aerogel, synthesized via a bio-friendly route, displays favorable magnetic properties and can be used to entrap biomolecules.