University of Pennsylvania engineers and physicians have developed a carbon nanopipette thousands of times thinner than a human hair that measures electric current and delivers fluids into cells. Researchers developed this tiny carbon-based tool to probe cells with minimal intrusion and inject fluids without damaging or inhibiting cell growth. Drexel University College of Engineering had previously developed carbon nanotube pipettes in 2007. This work is another step to realizing one aspect of the vision of nanomedicine.
Researchers believe the pipettes will be useful for concurrently measuring electrical signals of cells during fluid injection. In addition, the pipettes are transparent to X rays and electrons, making them useful when imaging even at the molecular level. Adding a functionalized protein to the pipette creates a nanoscale biosensor that can detect the presence of proteins.
“Penn’s Micro-Nano Fluidics Laboratory now mass-produces these pipettes and uses them to inject reagents into cells without damaging the cells,” Bau said. “We are ultimately interested in developing nanosurgery tools to monitor cellular processes and control or alter cellular functions. We feel CNPs will help scientists gain a better understanding of how a cell functions and help develop new drugs and therapeutics.”
Just as important as the mechanical properties of carbon nanopipettes, however, is the ease of fabrication, said Michael Schrlau, a doctoral candidate and first author of the study, “Carbon Nanopipettes for Cell Probes and Intracellular Injection,” published in the most recent issue of Nanotechnology. “After depositing a carbon film inside quartz micropipettes, we wet-etch away the quartz tip to expose a carbon nanopipe. We can simultaneously produce hundreds of these integrated nanoscale devices without any complex assembly,” he said.
The next challenge for researchers is fully utilizing the new tools in nanosurgery.
“We will need to go beyond the proof-of-concept, development stage into the utilization stage,” Schrlau said. “This includes finding the appropriate collaborations across engineering, life science and medical disciplines.”
Drexel University College of Engineering researchers had successfully developed carbon nanotube-tipped pipettes in April 2007. the pipettes could become key to cell biology in-situ DNA sequencing and organelle-targeted drug delivery. This development makes it possible to perform injections or probe the fluid, not just inside a cell, but in specific regions inside the cell, maybe even specific organelles.