Light-controlled nanoscale buzz saws kill cancer cells by drilling holes in them

Rice University scientists broke records in 2005 when they constructed the world’s smallest car, a single-molecule “nanocar” boasting a chassis, axles, and four wheels. More than a decade later, the same research lab is still working at the nanoscale level — although its latest project could provide a whole lot more benefit than just nanoscale car races. With help from researchers in the U.K. and at North Carolina State University, what Rice scientists have developed are tiny nanoscale motorized molecules that are designed to drill holes in the membrane of individual cells. Depending on whether these cells are bad or good, it can then kill them or, potentially, deliver healing drugs.

“In [our work], we showed that these molecular machines can selectively kill cancer cells,” Gufeng Wang, an assistant professor in analytical chemistry at N.C. State, told Digital Trends. “We expect that molecular machines could also be used in vivo to cure diseases. In general, this technology can be used as a highly efficient, highly specific drug-delivery method, or, simply as a way to kill cells directly by disrupting their material exchange with the environment.”

Wang hypothesizes that skin cancer is one condition that could be treated using the tiny molecular machines to kill its associated malignant cells. The molecular machines are activated using ultraviolet (UV) light to control their movements through fiber optics. Like tiny buzz saws, they are then able to spin at an astonishing 2 million to 3 million rotations per second to slice open the cell membranes.

At present, there are still limitations for the diminutive technology. For one thing, the shallow penetration depth of UV light means that currently only cells at the surface of tissues can be treated — limiting it to areas like skin. There are also concerns about potential overuse of the technology since overexposure to UV light is harmful.

“We are working on two directions to make this new method more viable,” Wang said. “The first is that we are developing visible light or even near infrared (IR) light-activated motors. The second is that we are trying to activate the same motor using near IR light through a process called multiphoton excitation. In this process, the motor will absorb two photons simultaneously, and get enough energy to start the rotor. If we are able to use red to near IR light to actuate the molecular machines, we are no longer limited to the surface of the tissue.”

A paper describing the work was recently published in the journal Nature.

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