Method to sense single-particle motion using a tapered-gap microcapacitor

摘要

We present an approach to study the real-time dynamics of single molecules using capacitance measurements. The method is based on a nonparallel-plate microcapacitor, which has a tapered-gap geometry. A particle moving within such a capacitor induces capacitance changes that depend on its position. Monitoring these changes allows motion to be traced at a resolution which is higher than the smallest fabricated feature of the device. The detection scheme also enables the distinction between particles of different dielectric constants and the exertion of dielectrophoretic forces on the particles. This approach provides a means for studying various aspects of single-particle dynamics at high resolution, in real time, and under conditions compatible with biological systems.