Dec 6, 2007
Carbon nanopipettes for cell probes and intracellular injection
Cells are the basic building blocks of life. The ability to probe and affect cell machinery is essential for gaining a better understanding of cell function and for developing new drugs and therapeutics. Due to the small size of cells, cell probing is a challenge.
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.
About the author
Haim H Bau is a professor of mechanical engineering and applied mechanics at the University of Pennsylvania, Philadelphia, USA. He is currently conducting research on micro and nanofluidics phenomena with applications in biology and medicine. The article was co-authored by Michael Schrlau, a PhD candidate in the Micro-Nano Fluidics Laboratory. The work was carried out in collaboration with Professor B Ziober and Erica Falls from Penn’s School of Medicine. The work was supported, in part, by grant NSF IIP 0637786 to Vegrandis, LLC, with a subcontract to the University of Pennsylvania and by the State of Pennsylvania through the Nano Technology Institute, Seed Grant No. UP028.