Scientists use carbon nanotube forest to capture hard-to-detect molecules

A zoomed-in view of the carbon nanotubes, arranged vertically in what the researchers describe as being "like trees in a forest"(Credit: MIT)

Researchers at MIT have developed a new method for detecting elusive molecules, using an array or "forest" of carbon nanotubes. The technique can be finely tuned, allowing it to be used for the capture of very small particles, including those of certain viruses.

Carbon nanotubes have been the subject of many studies, with researchers working to harness their potential for various purposes, from small sensors that can detect spoiled meat, to anti-icing coatings for aircraft. Now, an MIT research team has turned the material towards capturing tiny bioparticles.

The new method makes use of carbon nanotubes which have been manipulated to stand on their ends, creating an array that the team describes as being "like trees in a forest." Taking advantage of the fact that the material is 99 percent porous, the arrangement allows for the creation of a three-dimensional, highly permeable array within a microfluidic device.

The researchers coated the vertically-arranged nanotubes in successively layers of alternately charged polymer solutions, giving the array the ability to trap certain particles. This ability can be tuned by chemically treating the nanotubes, allowing select molecules to be captured.

During testing, the team treated the nanotubes with antibodies that bind to prostate specific antigen (PSA), before pumping a solution containing small amounts of PSA through the array. The coating was found to trap 40 percent more antigens than a non-coated version of the array, with molecules captured throughout the structure rather than just on the outer surface, as is common with typical microfluidic systems

Thanks to its highly versatile nature, the nanotube array could end up being an extremely useful tool. In particular, it could prove effective at targeting tiny biomarkers called exosomes, which have a width of less than 100 nanometers.

"There are smaller bioparticles that contain a very rich amount of information that we don't currently have the ability to access in point-of-care [medical testing] devices like microfluidic chips," says MIT's Brian Wardle. "Carbon nanotube arrays could actually be a platform that could target that size of bioparticle."

The findings of the research were published in the Journal of Microengineering and Nanotechnology.

Source: MIT

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