Richard B. Brown - Research
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Electron-Relay Enabled Immunosensor Using Magnetic Microprobes
Graduate Student Researchers: Daniel J. Burke, Robert Franklin

Illustration of Immunosensor Concept; (a) magnetic bead with gold monolayer. (b) immobilization of molecular wires and antibody Fab fragments on gold. (c) simplified conductimetric sensing concept.

This project's goal is to develop a new immunosensor technology that will form the core of a rapid-analysis immunoassay microsystem. The sensing approach requires the self-assembly of both antibody Fab fragments and electron-relay enhanced polymers onto gold-coated magnetic microspheres. During the sensing process, the beads are magnetically confined to an interdigitated gold electrode surface once their antibodies have selectively bound and immobilized their target analyte. The aggregate electrical conductivity of the electron-relay-enhanced microspheres can then be measured through currents resulting from the applica­tion of small DC potentials (10-500mV), the magnitude of which depend on the molecular wire used. Disulfide-terminated poly-L-lysine molecular wires have been successfully synthesized for experiments of self-assembly on gold surfaces. Additionally, a non-planar electroless gold plating process has been developed in order to achieve uniform gold-coating of commercial magnetic beads. Recent studies have investigated the fabrication of microfluidic test structures with inno­vative and inexpensive PCB technology, as well as optimization of the various component assembly processes. This project is funded by the Michigan Life Sciences Corridor, MLSC, under project number 001560.