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Precisely Delivering Chemical Cargo to Cells
Janelle Weaver
Posted October 21, 2010

This movie shows the manipulation of nanowires for drug delivery to a single cell. Chien and post-doc Donglei Fan led the nanowire fabrication, manipulation and positioning on the targeted cells, while Levchenko and post-doc Zhizhong Yin carried out the bio-related and simulation work.
This movie shows the manipulation of nanowires for drug delivery to a single cell. Chien and postdoc Donglei Fan led the nanowire fabrication, manipulation and positioning on the targeted cells, while Levchenko and postdoc Zhizhong Yin carried out the bio-related and simulation work. Credit: Nature Nanotechnology

The protein, tumor necrosis factor alpha (TNFα), may be powerful against cancer, but it can also be deadly to other cells. If its concentration builds up too high throughout the body, TNFα can disrupt organ function and cause septic shock. That's why it's important to move the protein and other molecules to specific cells. Until now, this has been a major biological challenge.

By partnering, two labs at Johns Hopkins University have come up with a technique for delivering chemicals to individual cells. The approach uses gold nanowires to carry the tumor-killing protein.

After several years of work, scientists in the lab of physicist Chia-Ling Chien developed electric tweezers that could manipulate gold nanowires. In 2008, they started talking to colleagues in the lab of biomedical engineer Andre Levchenko. The two groups speculated that the nanowire technology could be used to precisely deliver drugs to single cells.

For this work, they coated the wires with a negatively charged molecule. This allowed them to manipulate the orientation and movement of the wires using electric fields and, as a result, control where TNFα was released. The scientists could deliver a single nanowire at a time and drop it onto the surface of a single cell. They could also transport multiple nanowires, carrying more of the protein to each cell. They used a combination of computational modeling and experiments to confirm that single cells, rather than many, responded to TNFα.

Next, they hope to use the technology to deliver therapeutic chemicals to tumors.

Learn about related research

This page last reviewed on April 22, 2011