Cotton Candy Tech Goes Nano
Kit Parker, Disease Biophysics Group at the Harvard School of Engineering and Applied Sciences
The rotary drum (left) spins out soft nanofibers (above right), which look even cooler viewed at 10µm.
Rarely do the worlds of nanotech and carnival cuisine overlap, but when they do the results can be pretty sweet. A team of engineers has created a technology for fabricating nanofibers that's half high-speed centrifuge, half cotton candy machine, spinning and stretching out ultra-thin nanofibers that measure just 100 nanometers in diameter.
Like most technologies prefixed with "nano," this one has a wide range of applications in fields ranging from textiles to air filters to biotech. Moreover, it could drastically reduce the cost and complexity of nanofiber manufacture, making the tiny threads a cost effective option in countless products.
To produce nanofibers, manufacturers generally employ a technique called electrospinning, which involves shooting a high-voltage charge through a polymer liquid to extract long nanothreads. The threads themselves are fine, but the process offers little control and isn't really scalable to mass manufacture, not to mention it's a bit energy-intensive.
The new method opts for rotary jet spinning, which closely resembles the method used in cotton candy machines to draw out long wispy threads from molten sugar. The machine rapidly feeds a polymer material into a rotating drum then spins the material out into long, thin fibers through an extrusion needle. Fibers can be easily engineered to be thicker or thinner, have varying textures, or be spun directly into molds that shape them into 3-D structures. The result is more control, higher yields, and a far simpler overall process compared with electrospinning.
The team has already tested the device on a handful of synthetic and natural polymers, including the eco-friendly polylactic acid, otherwise knows as that biodegradable plastic that comes from corn starch. They even used it to form tissue scaffolds that allow biological matter to grow in controlled ways. By integrating heart tissue from rats into the nanofibers, they were able to grow beating muscle tissue in the lab. And all that's just for starters. Unlike cotton candy, this nanofiber tech should get better with time.