PITA Fiscal Year 2015 Projects

Polymer-Based Protein engineering to wire enzymes to electrodes

Lead University: Carnegie Mellon University
PI: Alan Russell, ICES and Islam Mohammad, Materials Science and Engineering

Enzyme-based platforms capable of sensing or deriving electrical power from physiological compounds have been a significant topic of research for many years. Enzymatic biosensors and biofuel cells rely on the specific catalysis of a target compound, such as glucose, at an electrode surface to provide electrons to drive the devices. The exceptional selectivity and specificity of enzymes coupled with their mild operating conditions make these biological catalysts ideal for miniature devices operating under physiological conditions, for example an implantable a biofuel cell using glucose as the fuel could both detect glucose levels and power an implanted insulin pump in an artificial pancreas. In this proposal we address a key limitation suffered by the enzymatic platforms, low power densities resulting from inefficient electron transfer kinetics. We propose to attack this issue from two directions: 1) by altering the surface of the protein to be more conductive; and 2) by developing novel electrodes composed of high surface area carbon materials. The two approaches are derived from work currently underway in the Principle investigators’ labs. The Russell group has developed technologies to grow polymers from protein surfaces. This process, which we call polymer-based protein engineering, will be mused to synthesize protein polymer conjugates in which the polymer is electrically conductive. These polymers would, in essence “wire” the enzyme directly to the electrode surface greatly improving the electron transfer kinetics. The Islam group has been developing novel high surface area low density carbon materials as electrodes. These materials, which use graphene and carbon nanotubes formed as aerogels and hydrogels, are highly conductive and can accommodate binding for sufficiently large amounts of enzyme to provide current densities to power a number of medical devices. The synergy of these two technologies will result in revolutionary detectors and power supplies for the medical devices industry.