Engineered nanofluidic platforms for single molecule detection, analysis and manipulation

Abstract

Since the pioneering studies on single ion-channel recordings in 1976, single molecule methods have evolved into powerful tools capable of probing biological systems with unprecedented detail. In this work, we build on the versatility of a type of nanofluidic devices, called nanopipettes, to explore novel modes of single molecule detection and manipulation with the aim of improving spatial and temporal control of biomolecules. In particular, a novel nanopore configuration is presented, where biomolecules were individually confined into a zeptoliter volume bridging two adjacent nanopores at the tip of a nanopipette. As a result of this confinement, the transport of biomolecules such as DNA and proteins was slow down by nearly three orders of magnitude, leading to an improved sensitivity and superior signal-to-noise performances compared to conventional nanopore sensing. Active ways of controlling the transport of biomolecule by combining the advantages of nanopore single-molecule sensing and Field-Effect Transistors are also presented. These hybrid platforms were fabricated in a simple two step process which integrates a gold electrode at the apex of a nanopipette. We show that these devices were effective in modulating the charge density of the nanopore and in actively switching "on" and "off" the transport of DNA through the nanopore. Finally, a nanoscale dielectrophoretic nanotweezer device has been developed for high resolution manipulation and interrogation of individual entities. Two closely spaced carbon nanoelectrodes were embedded at the apex of a nanopipette. Voltage and frequency applied to the electrodes generated a highly localized force capable of trapping and manipulating a broad range of biomolecules. These dielectrophoretic nanotweezers were suitable for probing complex biological environments and a new technique for minimally invasive single-cell nanobiopsy was established. Such study provides encouraging results on how nanopipettebased platforms can be integrated as a future tool for routinely interrogating molecules at the nanoscale.Open Acces