A Single-Protein Wet Biotransistor

A single-protein wet biotransistor has been devised by physicists at the INFM-S3 Center in Modena, Italy. Metalloproteins help to shuttle electrons among molecules, a necessary task for powering such life-critical functions as respiration, photosynthesis, and enzyme reactions. To do this the protein bristles with side chains where binding can be achieved.

Why not harness all this functionality normally used for keeping an organism alive for performing digital information processing? Paolo Facci (p.facci@unimo.it, 39-059-205-5654) and his colleagues use a particular bacterial protein called azurin in a strategic position between two gold electrodes, which act as the source and drain of a transistor. A third electrode, acting as the gate, enables the centrally located azurin to allow the passage of an electrical current (see figure at www.aip.org/png).

The whole process takes place in a wet environment, the first time a single-protein bio-transistor has been operated in this way. Facci believes that with the addition of bio-inorganic electrodes, his bio-transistor could be implemented in various wet situations, such as serving in brain-machine interfaces or for sensing cellular events. (Alessandrini et al., Applied Physics Letters, 28 March, 2005; lab site at www.s3.infm.it )