Sean Fischer

From Murmann Mixed-Signal Group

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BSEE, University of Connecticut, 2013

MSEE, Stanford University, 2015

Ph.D. Candidacy, Stanford University, 2015 - present

Email: seanrf AT stanford DOT edu

Electronic Instrumentation for Enabling Affinity-Probe Free Protein Detection

Measurement of protein concentration in blood is important for diagnosis and treatment of disease. Conventional methods of detection use affinity probes which bind to the protein under consideration, separating it from the sample background and labeling it with an observable tag. The chemical processing steps needed for these techniques introduce significant overhead, increasing the cost per detection and degrading patient outcomes. A method of protein detection proposed in [1] addresses this problem by eliminating the need for chemical processing. In this approach, the energy of vibrational modes intrinsic to proteins in the sample modulate the conductance of a nanoscale working electrode in an electrochemical cell. Instead of chemical affinity, the target protein is isolated from the sample background using a computational algorithm. The transduction mechanism is rooted in quantum-mechanical concepts previously observed experimentally in metal-insulator-metal junctions at cryogenic temperatures [2]. In this research project, we observe similar quantum-mechanical charge transfer in an electrochemical system at room temperature. These measurements are enabled by co-design of the nanoscale working electrode and the low-noise electronics which drive it. 

[1] C. Gupta, R.M. Walker, S. Chang, S. Fischer, M. Seal, B. Murmann, and R.T. Howe, "Quantum Tunneling Currents in a Nanoengineered Electrochemical System," The Journal of Physical Chemistry, pp. 15085-15105, July 2017.

[2] J. Lambe and R.C. Jaklevic, “Molecular Vibration Spectra by Inelastic Electron Tunneling,” Phys. Rev., Vol. 165, No. 3, pp. 821-832, Jan. 1968.


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