Search

Our research focuses on using silicon microfabrication to develop quantitative, high throughput and realtime techniques for measuring biomolecular interactions. Over the last year, we have developed a new detection method where specific biomolecules adsorb to the walls of a suspended microchannel resonator and thereby lower its resonant frequency. Confining the fluid to the inside of the resonator significantly increases sensitivity by eliminating high damping and viscous drag. It also enables direct integration with conventional microfluidic systems and allows the resonator to be actuated by electrostatic forces. In this presentation, I will introduce the resonator, show recent progress towards achieving its fundamental limit of detection, and outline a path towards high throughput measurement for systems biology.

We report the selective and real-time detection of label-free DNA using an electronic readout. Microfabricated silicon field-effect sensors were used to directly monitor the increase in surface charge when DNA hybridizes on the sensor surface. The electrostatic immobilization of probe DNA on a positively charged poly-l-lysine layer allows hybridization at low ionic strength where field-effect sensing is most sensitive. Nanomolar DNA concentrations can be detected within minutes, and a single base mismatch within 12-mer oligonucleotides can be distinguished by using a differential detection technique with two sensors in parallel. The sensors were fabricated by standard silicon microtechnology and show promise for future electronic DNA arrays and rapid characterization of nucleic acid samples. This approach demonstrates the most direct and simple translation of genetic information to microelectronics.