Currently, our main research efforts are aimed at developing nanosensors for medical diagnostics that employ nanoscale physical and chemical effects to enhance the sensitivity of detecting ultra-low concentrations of target molecules in small sample volumes. We have basic knowledge in surface chemistry and extensive experience in packaging and integration of sensors into microfluidic platforms and the associated design and implementation of microfluidic hydraulic systems for the preparation of nanoliter volume samples.

We have recently developed a small sample volume microfluidic analytical microsystem with integrated nanowire biosensors that are being used to detect the hybridization of certain nucleic acid sequences using an all-electrical readout. We have developed a differential measurement configuration that provides the capability to cancel environmental sources of noise and interference yielding measurements that better represent hybridization events compared to single sensor configurations. The differential measurement configuration reduces sensor drift by a factor of 30x, and provides signal amplification. In connection with differential measurements, we have developed new surface chemistry methods to print receptor biomolecules on single nanowires over large areas with a spatial resolution of a couple microns and with horizontal orientation.

Over the last two decades surface plasmon resonance biosensor systems have emerged as the standard pseudo-label-free and real-time measurement technique especially for the estimation of binding affinities of different receptor-target molecular systems, such as DNA hybridization, protein-protein interactions and antibody-antigen binding. We have reported several surface plasmon resonance imaging biosensor systems with integrated multiplexed microfluidic interfaces for biomolecular screening and drug screening. Our multiplexed surface plasmon resonance imaging assays simultaneously monitor hundreds of different real-time biomolecular interactions and scaling up to larger multiplexed arrays is limited only by the availability of suitable biomarkers. We currently use surface plasmon resonance imaging extensively for the estimation of the binding affinities of large molecular weight molecules and as a standard control for high sensitivity biosensor and surface chemistry development in our laboratory.