Penn engineers create carbon nanopipettes that are smaller than cells and measure electric current

January 15, 2008
Penn engineers create carbon nanopipettes that are smaller than cells and measure electric current
From top to bottom: the carbon pipe tip of the CNP buckles when pushed against the wall of a glass pipette and recovers its initial shape once the force is removed. (b) From top to bottom: a CNP penetrates through the membrane of a smooth muscle cell. The cell is held in place by glass micropipette aspiration. Scale bars, 15 µm. Credit: Reprinted with permission from IOP Publishing

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.

Glass micropipettes are found in almost every cell laboratory in the world but are fragile at small scales, can cause irreparable cell damage and cannot be used as injectors and electrodes simultaneously. Haim Bau, a professor in the Department of Mechanical Engineering and Applied Mechanics at Penn, and his team developed tiny carbon-based pipettes that can be mass-produced to eliminate the problems associated with glass micropipettes.

Although they range in size from a few tens to a few hundred nanometers, they are far stronger and more flexible than traditional glass micropipettes. If the tip of a carbon nanopipette, or CNP, is pressed against a surface, the carbon tip bends and flexes, then recovers its initial shape. They are rigid enough to penetrate muscle cells, carcinoma cells and neurons.

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."

Source: University of Pennsylvania

Explore further: 'Harmful' effects paradoxically enhance solar cell efficiency

Related Stories

'Harmful' effects paradoxically enhance solar cell efficiency

November 12, 2015

(—Dissipation and decoherence are typically considered harmful to solar cell efficiency, but in a new paper scientists have shown that these effects paradoxically make the exciton lifetime in semiconducting carbon ...

Microwave field imaging using diamond and vapor cells

November 10, 2015

Microwave field imaging is becoming increasingly important, as microwaves play an essential role in modern communications technology and can also be used in medical diagnostics. Researchers from the Swiss Nanoscience Institute ...

Recommended for you

Physicists develop new technique to fathom 'smart' materials

November 26, 2015

Physicists from the FOM Foundation and Leiden University have found a way to better understand the properties of manmade 'smart' materials. Their method reveals how stacked layers in such a material work together to bring ...

Mathematicians identify limits to heat flow at the nanoscale

November 24, 2015

How much heat can two bodies exchange without touching? For over a century, scientists have been able to answer this question for virtually any pair of objects in the macroscopic world, from the rate at which a campfire can ...

New sensor sends electronic signal when estrogen is detected

November 24, 2015

Estrogen is a tiny molecule, but it can have big effects on humans and other animals. Estrogen is one of the main hormones that regulates the female reproductive system - it can be monitored to track human fertility and is ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.