Tuesday, May 26, 2015

Biophotonics Faculty Candidate Seminar: "Stimulated Raman: Building Better Biosensors, Making Medical Discoveries, and Understanding Fundamental Biophysics" by Dr. Ryan M. Gelfand 5.28.15/11:00am-12:00pm/CREOL RM 102

Seminar: "Stimulated Raman: Building Better Biosensors, Making Medical Discoveries, and Understanding Fundamental Biophysics" by Dr. Ryan M. Gelfand
Thursday, May 28, 2015 11:00 AM to 12:00 PM
CREOL Room 102

Celebrating the International Year of Light 2015

Dr. Ryan M. Gelfand 

For over a century optical spectroscopy has been an integral tool for determining the structure, composition, and function of biological molecules. When small molecules bind together to form macromolecules the intermolecular resonances are found between 0.3 to 10 THz: the terahertz gap. Current sources and detectors at these frequencies are impractical for large scale, fast, sensitive and inexpensive molecular studies. By using the beat frequency between two laser sources one can perform high resolution spectroscopy across a very large frequency range (including the THz regime) while still using readily available visible and NIR optical components. This frequency difference creates a strong electrostriction force that excites Raman active vibrational modes. Once excited, the increased motion of the particle influences the optical signal which can be recorded by using a lock-in amplifier. To increase the efficiency and sensitivity of this technique it is coupled to a single nanoparticle optical aperture trap. Within this trap one can study the structure of proteins without tethers and in their native environment; comparing how different therapies impact the behavior of these important biological molecules. Development of this technique will enable researchers to gain insight into both protein-protein and protein-small molecule interactions leading to advances in disease treatments, potentially for neurodegenerative disorders. Furthermore, because the setups are versatile they can be used to study other nanoparticle systems as well (for example: semiconductors, carbon materials, florescent molecules, etc).
These stimulated Raman methods are not only simply limited to optical traps. By using them in conjunction with an AFM, this spectroscopic functionality can be added to force microscopy measurements. By looking at the effect of an excited particle near a plasmonic hotspot fabricated onto the facet of one of the lasers, sensitive and selective optical detection can be achieved by looking at the change in differential resistance of the laser. This would eliminate the need for bulky, cooled photodetectors and enable compact, portable, and potentially disposable biosensor devices. Two photon stimulated Raman techniques will allow us to more easily access the THz region, add extra spectroscopic functionality to already existing methods, and provide researchers with a new tool to study fundamental sciences.

Dr. Ryan M. Gelfand is an NSF funded postdoctoral researcher in electrical engineering at the University of Victoria with Prof. Reuven Gordon and Northwestern University. He received his Ph.D. in electrical engineering (solid state and photonics division) from Northwestern with Prof. Hooman Mohseni, and his B.S. in physics from Carnegie Mellon. Between those degrees he worked as a pharmaceutical chemist for Abbot Labs in Chicago. Ryan was awarded an NSF Fellowship in Biology in 2013 for a program entitled: Intersections of Biology and Mathematical and Physical Sciences and Engineering. His research interests and experiences have always been at the intersection between the physical sciences and biology.

For additional information:
Dr. Aristide Dogariu


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