From Murmann Mixed-Signal Group
MSEE, Stanford University, Fall 2015
BSEE, University of Connecticut, 2013
Potentiostat Array for Molecular Diagnostics
The diagnosis and treatment of disease would be enhanced by the ability to identify disease at the molecular level regardless of patient condition or location. The capabilities offered by point-of-care testing would provide precise, rapid, and affordable diagnosis, improving the chance of positive patient outcomes through timely and effective treatment. Current molecular diagnostic systems are incapable of fulfilling this need, as they require stockpiles of refrigerated chemical labels and laboratories equipped with bulky measurement tools. Despite decades of research, however, label free diagnostic techniques which do not require benchtop equipment have yet to make an impact on the healthcare industry.
This research project is a bio-inspired molecular diagnostics platform which promises to revolutionize point-of-care testing. The system works similar to the olfactory system in fruit flies, which biologists believe sense the vibrations of odorous molecules by measuring tunneling currents. Extracting vibrational information from tunneling currents is fundamentally challenging due to thermal noise, which in the past has required cryogenic cooling. To overcome this problem, we have designed and implemented a board level circuit which reduces the effective temperature of a novel electrochemical sensor through electronic noise cooling. Preliminary results show that we can distinguish biologically relevant proteins using the vibrational spectra measured using our noise-cooling circuit [1, 2]. We are currently designing an integrated potentiostat capable of driving the next-generation molecular diagnostic sensor array. Once integrated, our bio-inspired handheld molecular diagnostics platform will enable precise, rapid, and affordable point-of-care testing for the diagnosis of disease, providing remote areas of the globe with quality healthcare. Combined with IoT, our system will enable electronic monitoring for personalized medicine and population monitoring for tracking contagious disease. In laboratory environments, label free electronic molecular diagnostics will enable greater productivity and creativity for fundamental scientific research in chemistry, biology, pharmaceuticals, and medicine.
 C. Gupta, R. M. Walker, R. Gharpuray, M. M. Shulaker, Z. Zhang, M. Javanmard, R.W. Davis, B. Murmann, and R. T. Howe, “Electrochemical quantum tunneling for electronic detection and characterization of biological toxins,” Proceedings of SPIE, vol. 8373, p. 837303 (14pp), 2012.
 R. M. Walker, “Interface electronics for emerging sensor systems,” Ph.D. dissertation, Dept. Elect. Eng., Stanford Univ., Stanford, CA, 2013.