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3D Gold Interdigitated Electrodes Array (IDEA) biosensor

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3D gold Nanogap interdigitated electrode array biosensor for highly specific and sensitive detection of biomolecular interactions Kanwar Vikas Singh, Allison M. whited, Gopichand Nandamuri, Dheeraj Bhura and Raj Solanki Department of Physics, Portland State University 1719 SW 10th Ave, Portland (Or) 97201 Described herein is a label free nanogap interdigitated electrode array impedimetric biosensor for biomolecular interactions. 3D gold interdigitated electrodes design with nanometer spacing showed better characteristics as compared to planar electrodes with device modeling. It was observed that by decreasing the gap between the electrode digits better signal generating parameters were observed for the sensor such as electric field (E)and current density (J). The nanogap interdigitated electrodes were materialized using a combination of photolithography and e-beam lithography using gold metal. Several different electrode digit gaps (G) and digit Width (W) combination were made and characterized using SEM, AFM and Electrochemical Impedance spectroscopy for physical and electrochemical attributes. A 3:1 (W:G) ratio with a 500nm interdigit gap was found to be best suitable for mass production. The 3D interdigitated gold electrodes array chip was designed with the standard digital card format electrode configuration that can be incorporated into a small handheld microfluidic device. The chip was used for detection of Transglutaminase (TG) specific Antibodies, a highly specific biomarker for detection of celiac–sprue disease (wheat allergy). The comparison of impedance changes at selective frequencies showed highly specific detection of TG specific Antibodies at concentrations as low as 10pg/mL. the sensor showed dynamic detection range between 1ng/mL to 10ug/mL. The EIS results and equivalent circuit modeling and fitting of parameters showed an increase in charge transfer resistance with increasing biomolecular interaction events at the surface of the electrode. This indicated that enhanced binding of Antibodies on the electrode surface impeded the electron flow between the electrolyte and the electrode. Poster ID: 994015779 at ALA-2010, Palm Springs, CA (USA)