Dr. John E. Baur
Office – SLB 215, Lab SLB 214 Phone – 8-2663, Email – jebaur@ilstu.edu
Microscopic Sensors for Neurochemical Measurements
Research in our group focuses on the design, characterization, and application of microscopic chemical sensors. These sensors, only a few µm in size (the diameter of a strand of hair is about 100 µm), can measure concentration changes of chemical species in real time with high spatial resolution. Typical applications for the sensors developed in this lab are in vivo and in vitro measurements of neurotransmitters, chemical characterization of surfaces, and investigations into the mechanisms of corrosion. Members of this research group develop skills in advanced instrumentation, fabrication of microscopic structures, and computer interfacing and data acquisition.
Scanning Electrochemical Microscopy
The Scanning Electrochemical Microscope (SECM) is a valuable new tool for studying the distribution of chemical species near a surface. This instrument is a type of scanning probe microscope (SPM) in which the probe is a microelectrode (an electrode with dimensions of a few µm). A significant advantage of the SECM over other types of microscopes is that topographical and chemical imaging can take place simultaneously. See the tutorial at http://www.msstate.edu/Dept/Chemistry/dow1/secm/secm.html for an introduction to this technique.
In this project, we are developing probes and methods capable of imaging single biological cells withchemical selectivity and high resolution. The ultimate goal is to image model neuronal cells and
simultaneously monitor site-specific neurotransmitter release. We are presently using PC12 cells as the model neuron. When exposed to nerve growth factor (NGF) these cells extend neurites. These neurites present imaging challenges, as they are much lower and narrower than the cell proper, but reach lengths of tens or hundreds of µm. We are working to overcome these challenges by implementing constant height imaging, a technique in which the probe is moved vertically to trace the contour of the cells.