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With funding from the National Institutes of Health, Dr. David Dandy has led an interdisciplinary team in the successful development of a novel integrated optical waveguide biosensor platform. Recent laboratory results are so compelling that the premier micro-analytical methods journal, Lab on a Chip, will feature the work as the cover article in its August 7, 2009 issue.

The article, “Label-free silicon photonic biosensor system with integrated detector array,” is the result of an ongoing collaboration between Dr. Dandy and Dr. Kevin Lear, a faculty member in electrical engineering who guided these latest experiments.

The article describes an integrated, inexpensive, label-free photonic waveguide biosensor system with multi-analyte capability has been implemented on a silicon photonics integrated circuit from a commercial CMOS line and tested with nanofilms. The local evanescent array coupled (LEAC) biosensor is based on a new physical phenomenon that is fundamentally different from the mechanisms of other evanescent field sensors. Increased local refractive index at the waveguide's upper surface due to the formation of a biological nanofilm causes local modulation of the evanescent field coupled into an array of photodetectors buried under the waveguide. The planar optical waveguide biosensor system exhibits sensitivity of 20%/nm photocurrent modulation in response to adsorbed bovine serum albumin (BSA) layers less than 3 nm thick. In addition to response to BSA, an experiment with patterned photoresist as well as beam propagation method simulations support the evanescent field shift principle. The sensing mechanism enables the integration of all optical and electronic components for a multi-analyte biosensor system on a chip.

Additional information and publications may be found on Dr. Dandy’s web site.




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Department of Chemical and Biological Engineering
Colorado State University
1370 Campus Delivery
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