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A paper describing research in the MEMS Sensors and Actuators Laboratory has been published in Biosensors and Bioelectronics, the principal international journal devoted to research, design, development and application of biosensors and bioelectronics.
?A microfluidic-based electrochemical biochip for label-free diffusion-restricted DNA hybridization analysis? was written by Postdoctoral Fellow Hadar Ben-Yoav; alumnus Peter Dykstra (ECE Ph.D. 2011); Robert E. Fischell Distinguished Professor and Chair William Bentley (BioE); and ISR Director Reza Ghodssi, the Herbert Rabin Distinguished Chair in Engineering (ECE/ISR). It describes a new biosensing approach that applies a diffusion-restriction model to a microfluidic-based nanovolume reactor in order to accurately characterize DNA hybridization events. This is significant for improved performance of the next generation of biosensors using Lab-on-a-Chip devices and systems.
DNA hybridization detection in microfluidic devices can reduce sample volumes, processing times, and can be integrated with other measurements. However, as device footprints decrease and their complexity increase, the signal-to-noise ratio in these systems also decreases and the sensitivity is thereby compromised. Device miniaturization produces distinct properties and phenomena with greater influence at the micro-scale than at the macro-scale. In the research, a diffusion-restriction model was applied to a miniaturized biochip nanovolume reactor to accurately characterize DNA hybridization events that contribute to shifts in both charge transfer resistance and diffusional resistance. These effects are shown to play a significant role in electrochemical impedance spectroscopy (EIS) analyses at these length scales. The resulting highly functional microfluidic biosensor enables the detection of ssDNA targets selectively, with a calculated detection limit of 3.8 nM, and cross-reactivity of 13% following 20 min incubation with the target. This new biosensing approach can be further modeled and tested elucidating diffusion behavior in miniaturized devices and improving the performance of biosensors.
August 1, 2012
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