To address this challenge, the Micro-Nano Fluidics Laboratory at the University of Pennsylvania, under the direction of Professor Haim Bau, has developed integrated carbon nanopipettes (CNP) with tip diameters ranging from a few tens to a few hundreds of nanometers. The nanopipettes are made of carbon deposited inside catalyst-coated, pulled-glass capillaries. Subsequent to the carbon deposition process, the tip of the capillary is etched away to expose a carbon nanopipe. The process has the advantage of providing an integrated device without the need for cumbersome assembly. The resulting electrically conducting, nanoscale, carbon tips have good mechanical properties; they bend readily without breaking, yet they are sufficiently stiff to penetrate a cell’s membrane.

Recently, in collaboration with researchers from the School of Medicine at Penn, Michael Schrlau, a doctoral student in the Micro-Nano Fluidics Laboratory, demonstrated the utility of the CNPs for injecting reagents into cells without damaging them.

Future work will focus on measuring the cell’s electrical potential concurrently with the injection process and on developing arrays of CNPs that can concurrently interact with a large number of cells. Due to their transparency to electrons and X-rays, the CNPs might also be used as sample holders in transmission electron microscopy and X-ray studies.