Bandages are great for standard cuts and scrapes. However, when you get a cut in an area that’s not so easy to bandage — for example, between your fingers or toes — finding a bandage that will stay in place to protect the wound is serious business. New solutions require medical device testing.
Yosuke Okamura, Ph.D., had a solution to this problem in mind when he created a new kind of bandage. The new design uses ultra-thin, transparent, sticky, and extraordinarily flexible nanosheets made of the biodegradable polyester poly-L-lactic acid (PLLA). The thin coating clings to bends and wrinkles in the skin while still adhering to flat and broad surfaces. It does this without the addition of adhesives, making it an ideal bandage for any type of wound.
“The nanosheets can adhere not only to flat surfaces, but also to uneven and irregular surfaces without adding any adhesives,” said Okamura, a researcher at the Department of Life Science and Medical Bioscience Graduate School of Advanced Science and Engineering at Waseda University in Japan.
The PLLA is placed into a test tube with water and spun, disrupting the sheets and creating smaller pieces. The liquid and fiber are then poured out onto a flat surface where the fibers overlap and dry to form a thin nanosheet of material. The material’s ability to coat small and difficult contours was tested by dipping into the preparation irregularly shaped objects such as a needle and the digits from a mouse paw. The nanosheet covered each of the objects extensively, including the bends and wrinkles of the mouse digits. The material dried and stayed in place, keeping bacteria out.
But Wait, There’s More…
This discovery can change the way burn victims are cared for in hospitals. Burns are highly susceptible to infection. In order for a burn to heal properly, the bandage must be impenetrable to bacteria. The most common bacteria to infect a burn wound is Pseudomonas aeruginosa. It has also been known to cause skin infections and deadly hospital-induced infections. There are antibiotic-resistant strains that are very dangerous.
The nanosheet dressing was able to keep bacteria at bay for three days. Upon application of a second layer, the bacteria was kept out for six days. This level of protection from bacteria would significantly cut down on the number of dressing changes a burn patient will have to endure. It will also offer burn victims a chance to heal without the added worry of infection slowing the process or causing harm. The material has not yet been approved for human trials pending further medical testing for safety and efficacy.
And Even More…
The PLLA nanosheets are just the beginning. Okamura and his group have begun development on another highly flexible, fiber coating polymer with a phosphorylcholine group. The combined materials are compatible with blood and could be used as coatings on medical devices.
Thanks to the wonderful world of polymers, in the future those annoying cuts in hard-to-cover places or a burn from the grill will be covered completely, and nasty bacteria will be kept out.
Images by Yosuke Okamura.
“Cling Wrap For Burn Wounds: Biomaterial Nanosheets Coat Tricky Burns, Blocks Out Infection,” by Phys.org, www.phys.org, August 10, 2014
“Nanosheets To Protect From Burn Wound Infections,” by mangalorean, www.magalorean.com, August 11, 2014
“Fragmentation of Poly(lactic acid) Nanosheets and Patchwork Treatment for Burn Wounds,” Yosuke Okamura, et al., Advanced Materials, November 1, 2012, DOI: 10.1002/adma.201202851