Bioanalytical and Biophysical Studies of Chemical Microenvironments
The research of the Shear Labs is directed toward design and implementation of optical strategies for investigating the chemistry of neurotransmission at the greatest level of reduction -- the individual synapse. An ideal approach for probing neurotransmission on this scale would provide chemical profiles of many neurotransmitter species with millisecond time resolution and with sufficient sensitivity to assay the contents of the smallest packets (or "vesicles") of neurotransmitter -- approximately 1000 molecules. Toward these goals, Dr. Shear and his collaborators are actively involved in development of rapid microcolumn chemical separation procedures and novel detection approaches that draw on recent advances from a range of disciplines. They have investigated the use of nonlinear absorption as a means to excite fluorescence and photochemistry in femtoliter volumes, a strategy that yields significant improvements in the mass detectability of many neuroactive species. In one example, the mechanisms responsible for multiphoton-excited "photoderivatization" of hydroxyindoles were studied, and then this process was used to enhance the optical properties of serotonin and related metabolites.
"Electronic Tongue" Sensors
The Shear Labs is involved in collaborative research with several other groups in Chemistry and Engineering to develop microfabricated arrays capable of rapidly analyzing complex solutions for the presence of many analytes. These devices -- dubbed "electronic tongues" because of their conceptual similarity to the multicomponent sensors we carry in our mouths -- may eventually offer a highly flexible and rapid approach to the sensing of toxins, drug metabolites, and numerous biological components present at low concentrations in very small sample volumes.