Micromachined Linear Brownian Motor: Transportation Of Nanobeads By Brownian Motion Using Three-phase Dielectrophoretic Ratchet

摘要

Nanosystems operating in liquid media may suffer from random Brownian motion due to thermal fluctuations. Biomolecular motors exploit these random fluctuations to generate a controllable directed movement. Inspired by nature, we proposed and realized a nano-system based on Brownian motion of nanobeads for linear transport in microfluidic channels. The channels limit the degree-of-freedom of the random motion of beads into one dimension, which was rectified by a three-phase dielectrophoretic ratchet biasing the spatial probability distribution of the nanobead towards the transportation direction. We micromachined the proposed device and experimentally traced the rectified motion of nanobeads and observed the shift in the bead distribution as a function of applied voltage. We identified three regions of operation; (1) a random motion region, (2) a Brownian motor region, and (3) a pure electric actuation region. Transportation in the Brownian motor region required less applied voltage compared to the pure electric transport.