Nanobiotechnology offers the possibility of new forms of medical treatments, such as implantable devices that carry out biological or mechanical functions, or deliver drugs to specific tissues. Because proteins function so efficiently at this small scale, they will likely be major components of nanodevices. However, a number of important obstacles must be overcome for nanodevices to realize their potential. One of the most critical problems is how to supply implantable nanodevices with energy. Our work on the physiology of mammalian sperm has inspired us with a strategy to address this important issue. Sperm generate ATP throughout the flagellar principal piece by using glycolytic enzymes tethered to a cytoskeletal support by means of germ cellspecific targeting domains. We hypothesize that by identifying and modifying these domains, we can generate recombinant glycolytic enzymes that can be bound to a support and retain function. As proof of principle, we have made modified forms of the first two enzymes in this pathway, and show their activities in series when coupled to the same support. To our knowledge, this is the first demonstration of sequential enzymatic activities in a multi-step pathway on a hybrid organic-inorganic device. These data also support our hypothesis that sperm provide a natural model of how to produce ATP locally on nanodevices. We propose to construct similarly modified recombinant forms of the rest of the enzymes of glycolysis, as well as an additional enzyme that will be needed for co-enzyme regeneration. We shall then test the activities of these enzymes individually, in sub-assemblies, and in series on single supports in our effort to design a system through which implantable nanodevices can produce their own energy from freely available circulating glucose. If successful, our innovative strategy will produce an enabling technology that should advance a variety of medical applications for nanobiotechnology.
