Silica By Chemical Vapor Deposition (CVD): Towards Functional and Durable Bio-Interfaces

Abstract

It has clearly been demonstrated over the years that electricity can be derived from fuel cells that employ biological species such as enzyme, organelle or cells as the catalytic element. These fuel cells offer several advantages including high specificity, bio-friendly, ease of synthesis, and more over do not employ precious metal catalyst. Although bio based fuel cells possess these numerous advantages, however they are marred with issues such as lack of long-term stability, poor transport characteristics, and partial oxidation of most fuels resulting in overall low output of electrons. The design of fuel cells today is governed by obtaining parameters including minimal over potential, high current density, minimum transport losses and most importantly long-term stability. In order to achieve the desired properties we need to (a) control electron transport (mediated or direct) (b) effective immobilization technique for enzyme stabilization (3) high surface area and porous electrodes for high energy density and optimum fuel transport. In this talk, I will go over the promising new sol-gel based techniques to encapsulate biological entities that range from a few nm (enzymes, lipid bilayers) up to micron-sized species (cells and organelles) We have developed two novel techniques that are compatible and have been integrated with fuel cell technologies. The two approaches mainly are (a) CVD approach: chemical vapor deposition of inorganic silica precursors onto the electrodes that contain biological species (b) microwave approach: a rapid biocompatible approach that results in bulk-immobilization of biomolecules in solution and substrates. These process allows precise temporal and spatial control of silica polymerization kinetics through the control of precursor delivery at room temperature and does not require or produce high concentrations of injurious chemicals that can compromise the function of biomolecular assemblies therefore result in optimum immobilization of desired species.Secondly, I will talk about recent development in our lab of use of paper-based fuel cell that can power real devices including clock and LED. I will discuss the compatibility of immobilization techniques with paper based fuel cells and microbial fuel cells.