Sam Houston State University

Undergraduate Research
Summer 2011

Reproducible Sensor Positioning & Automation
Nathan Baker
Sam Houston State University

The surface enhanced Raman sensors that we prepare for detecting cyanide and cyanide metabolites are not perfectly uniform. To obtain the best signal and reproducibility from measurement to measurement we map the surface structure and then use this map and coordinate transformations to reproducibly locate different sensing regions in microscopy, extinction, surface enhanced Raman and other characterization experiments. Currently we do this manually, and not always completely, due to time constraints.  My project is to improve the efficiency and experimental simplicity of this process by automating it.  Specifically, I am working to incorporate a set of 3 National Aperture stepping motors coupled to linear lead screw stages (generously loaned to us by Dr. Darren Williams), into a computer controlled stage for reproducibly positioning the glass microscope coverslips on which we build our sensing surfaces. I'm currently working on the computer control interface. Once that is complete, the next step will be to incorporate the stage into the photo capturing process for characterizing sensor surfaces as they are built up: sphere masks, mesoporous thin films and completed sensors. The automation will enable us to characterize each slide with more images, and the same pattern of images. This will help us to systematize our quality control, and will also provide data for examining correlations between experimental sensing spectra (localized surface plasmon extinction spectra, surface enhanced Raman spectra, etc.), and microscopic surface morphology in different regions of the sensor surface.

Nathan calibrating our motors Our stepping motors