288343 A New Type of Silicon Nanofet Detector with Single-Nanoparticle Sensitivity

Wednesday, October 31, 2012: 2:35 PM
406 (Convention Center )
Denitsa Milanova1, Peter Griffin2, Matthew B. Kerby3, Thomas Niedringhaus4, R. Fabian Pease5 and Annelise E. Barron3, (1)Mechanical Engineering, Stanford University, Stanford, CA, (2)Electrical Engineering, Stanford University, (3)Bioengineering, Stanford University, Stanford, CA, (4)Chemical Engineering, Stanford University, Stanford, CA, (5)Stanford University

The next major cost reduction in bioanalysis will be accomplished with solid-state electronic detection, eliminating the need for UV or fluorescence signals and affiliated lasers, lenses, CCDs and dyes. Jumping onto this exciting bandwagon, we have designed, fabricated, and are testing a novel type of silicon Field Effect Transistor (FET) detection system for microfluidic devices. We believe that we can integrate this detector into a low-cost platform that will be beautifully applicable to the solid-state electronic analysis of electrophoresing biomolecules from low-volume samples. We created a planar sensor—no nanopore is necessary!—and fabricated the chips using conventional, scalable CMOS techniques. These sensors can be integrated into bioanalysis devices that, in their entirety, will be the size of a USB memory stick, and which will draw their power from and download their data to a laptop computer.

        Charged particles moving down a microchannel (hydrodynamically or electrophoretically) pass over a thinly insulated gate region. We took our inspiration from a new class of  charged proteins (e.g., BSA with a charge of -18) altered the gate potential by ~ 1 mV, to change the source-drain current by an easily detectable ~1 nA. This sort of electronic detection technology has inherent sensitivity up to one million times greater than electrode sensing or nanopore-current blockade measurements, because it measures perturbations to the flow of electrons through the silicon chip itself. Computational methods will translate high-speed electronic pulses into quantitative signals that encode specific information about the bioanalytes of interest. This technology has myriad exciting applications in the fields of proteomics, biomarker discovery, and diagnostics by providing a label-free method to sensitively identify and quantify biological material (e.g., proteins, DNA, RNA, viruses, cells) at the single molecule/particle level. We are aiming to develop our detector for genetic analyses, and will present experimental results for the analysis of anionic nano- and microspheres; and if all goes well, for DNA molecules too.

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