Title : Nanostructured biodevices based on carbon nanotubes and glyconanoparticles for bioelectrocatalytic applications
Abstract:
For four decades, the functionalization of electrodes by biomaterials based on electrogenerated polymers, carbon nanotubes and / or nano-objects, was widely used in the field of analytical chemistry and energy conversion for the design of biosensors and biofuel cells. Some new approaches for developing nanostructured biomaterials based on functionalized carbon nanotubes, will be briefly described as the compressions of carbon nanotubes, the self-assembly of carbon nanotubes in the form of buckypapers or the creation of hollow electrodes.
These different electrochemical materials combined with enzymes as catalytic element, will be applied to the design of glucose/oxygen enzymatic fuel cells and their performances will be compared. Examples of implantation of these biofuel cells in animals will be presented.
In particular, the concept of hollow bioelectrodes based on the assembly of two buckypapers was developed to generate a microcavity defined by the thickness of the glue linking the two sheets. These buckypapers are permeable only to water and enzyme substrates but not allow the permeation of enzymes. Therefore, the enzyme trapped in powder form is then solubilized inside the microcavity leading to a high density of biocatalyst in solution with an electrical connection with the buckypapers. The electrocatalytic performance of the bilirubin oxidase hollow electrode was described as a function of pH, temperature and the amount of entrapped enzyme. Owing to the complexity of optimizing a multienzyme system, this concept also constitutes an attractive strategy to design and optimize enzyme cascade reactions. Besides the easy modulation of enzyme ratios, we have also demonstrated the possibility of trapping with enzymes a redox mediator ensuring the electrical connection of an enzyme. On the other hand, the development of glyconanoparticles resulting from the self-assembly of block copolymers composed of polystyrene and cyclodextrin as an inclusion site will be also reported. These glyconanoparticles, which are stable in water, constitute a multivalent platform for binding hydrophobic fluorescent or electroactive molecules. These nanoparticles were applied to the elaboration of solubilized enzymatic fuel cell in solution or were grafted on surfaces for the development of amperometric enzyme electrodes.
