Abstract:  Recent years have seen the development of a broad class of optical and electrochemical biosensors in which the binding of a specific molecular target is signaled via a large-scale conformational change in its biomolecular receptor.  The reagentless, rapidly reversible nature of this signaling mechanism supports continuous, real-time measurement of a wide variety of analytes, and, when coupled to electrochemical read-outs, its extraordinary selectivity allows this detection to be performed in even the most grossly complicated samples, such as flowing, undiluted blood serum.  Like all processes reliant on single-site binding, however, these sensors still suffer from a potentially significant limitation. Specifically, the dynamic range of any given single-site receptor is centered at a fixed target concentration (defined by the receptor’s affinity) and spans a fixed range (defined by the shape of the Langmuir binding isotherm).  In this talk, I describe a number of mechanisms that evolution has invented in order to circumvent these same limitations, and demonstrate their utility in broadening, narrowing and otherwise “tuning” the useful dynamic range of artificial biosensors over many orders of magnitude. Bio:  Prior to joining the University of California at Santa Barbara in 1998 Dr. Plaxco received his Ph.D. from Caltech and performed postdoctoral studies at Oxford and the University of Washington. Dr. Plaxco has co-authored more than 130 papers on protein folding, protein dynamics, folding-based biosensors and folding-based smart materials. He has also co-authored a popular science book on Astrobiology and numerous patents. He is actively involved in the commercialization of the novel technologies emerging from his laboratory. Research Group Website: http://www.chem.ucsb.edu/~plaxcogroup/