The Research Laboratory of Electronics (RLE) at the Massachusetts Institute of Technology (MIT) announces that Dr. Roozbeh Ghaffari and Mr. Michael Vahey have won Helen Carr Peake Research Prizes for 2008.
Dr. Ghaffari is a February 2008 graduate of the Speech and Hearing Bioscience and Technology (SHBT) Program in the Division of Health Sciences and Technology (HST). His doctoral dissertation was supervised by Professor Dennis M. Freeman of RLE.
Dr. Ghaffari’s research addressed the behavior of the tectorial membrane, which is a microscopic gelatinous structure in the inner ear whose role in hearing is not well understood. It has long been known that sound produces traveling waves along the inner ear’s basilar membrane that are sorted by frequency in the propagation process and excite the sensory hair cells which transmit sound to the brain. However, existing models of the inner ear are unable to account for the enormous amplification that occurs in this process. Through nano-scale measurements, which required an entirely new class of measurement tools, Dr. Ghaffari demonstrated that sound induces longitudinally-propagating traveling waves in a tectorial membrane segment that was suspended between a fixed and a movable support. This hitherto unobserved phenomenon, which was reported in Proceedings of the National Academy of Science, might help explain the ear’s extraordinary spectral tuning and amplification. Moreover, this work could affect the design of hearing aids and cochlear implants, and it has implications for inherited forms of hearing loss that affect the tectorial membrane.
Mr. Vahey is a doctoral student in the MIT Department of Electrical Engineering and Computer Science (EECS) whose research is being supervised by Professor Joel Voldman in RLE.
Mr. Vahey’s doctoral research has led to a new microscale separation technique that sorts cells based upon their apparent electrical conductivity. Whereas standard separations based on dielectrophoresis suffer from effects due to variations in cell size, Mr. Vahey’s work, called iso-dielectric separation, avoids such problems by placing cells into a conductivity gradient in which they migrate until they reach the position at which their net polarization vanishes. Although conceptually simple, Mr. Vahey did careful analysis and numerical modeling to circumvent constraints and avoid the instabilities that prevented this technique from being demonstrated previously. With his devices, Mr. Vahey has successfully performed separations of both model particles and cells based upon a phenotypic marker. His research, which was just published in Analytical Chemistry, has broad implications for both biotechnology and medicine. For example, useful biological differences can manifest themselves as differences in electrical conductivity so that Mr. Vahey’s approach could then be used to reliably isolate the abnormal cells.
The selections of the award recipients were made by a committee consisting of Professor Freeman (MIT/RLE), Professor Jeffrey H. Shapiro (MIT, Director RLE), Professor M. Charles Liberman (Harvard, Director EPL), Professor William T. Peake (MIT/RLE/EPL) and Professor John L. Wyatt (MIT/RLE).