Trapping and identifying single-nanoparticles using a low-aspect-ratio nanopore

Manipulation of particles and molecules in fluid is a fundamental technology in biosensors. Here, we report electrical trapping and identification of single-nanoparticles using a low-aspect-ratio nanopore. Particle trapping and detrapping are implemented through a control of the cross-membrane electrophoretic voltage. This electrical method is found to enable placing an individual nanoparticle in vicinity of a lithographically-defined nanopore by virtue of the balance between the two counteracting factors, electrostatic and electroosmotic forces. We also demonstrate identification of trapped nanoparticles by the ionic current through the particle-pore gap space. This technique may find applications in electrode-embedded nanopore sensors. (C) 2013 AIP Publishing LLC.