(691g) Protein-Based Bioelectronic Devices

After billions of years of evolution, many proteins have developed the ability to transfer charge in a controlled and stable fashion from the environment to the protein's active site.  Prime examples are heme-containg proteins.  Exploiting this property in multifunctional (e.g., capable of sensing and computation) electronic circuitry could result in devices that are biocompatible and have a wide range of applications. In this talk I will describe recent efforts to make electronic devices out of proteins, and in the process, learn about the fundamental mechanism responsible for electron transfer in biological systems.  One example is an attempt to fabricate single electron transistors (SETs) using myoglobin, a heme protein found in muscle fibers. SETs were fabricated by depositing the protein on nanometer scale metal junctions which were broken via electromigration on n-Si/SiO2 substrates used as back gates.  By performing control experiments on blank junctions and apo-myoglobin (myoglobin without heme group), signals were observed that indicate single electron conductivity in a few devices.  In another example, cytochrome P-450 proteins were immobilized on gold pillars less than 30 nm in diamter, and their electrical conductance was measured using conducting probe atomic force microscopy (CP-AFM).  Systematic changes in the conductance of these proteins (in dry conditions) when bound to different small molecules were found to mirror the effects of these molecules on the known metabolic activity of the protein.  These experiments show that it may be feasible to make advanced biocompatible electronic devices in the near future.  

This work was supported by the National Science Foundation (grant EPS-1003907) and the National Institutes of Health (GM-086891).