Wrapping wound dressings around fingers and toes can be tricky, but for burn victims, guarding them against infection is critical. Recently, scientists reported creating novel, ultrathin coatings called nanosheets that can cling to the bodys most difficult-to-protect contours and keep bacteria at bay.
The researchers presented their materials Aug. 10 at the 248th National Meeting & Exposition of the American Chemical Society in San Francisco. So far, the materials have been tested on mice.
According to scientist Yosuke Okamura, PhD, existing wound dressings work well when it comes to treating burns on relatively flat and broad areas.
But the human body has curves, wrinkles and ridges. So Okamuras team developed a novel biomaterial out of tiny pieces of nanosheets that are extremely flexible and sticky.
The nanosheets can adhere not only to flat surfaces, but also to uneven and irregular surfaces without adding any adhesives, Okamura said in a news release.
That would make a big difference in the way burn victims are treated. According to the CDC, someone is injured by fire every 30 minutes.
Burn wounds are vulnerable to infection, and keeping them sealed off from bacteria is essential for a successful recovery.
Okamuras team at Tokai University, Tokyo, makes the nanosheets out of a biodegradable polyester called poly(L-lactic acid), or PLLA. They put the material into a test tube with water and spin it, which breaks up the sheets into smaller pieces. When they pour the liquid onto a flat surface, the tiny fragments overlap in a patchwork and dry as a single nanosheet.
The researchers tested the nanosheets ability to coat small and irregular shapes by dipping different items into the mixture, including a metal needle and a mouses toes. The nanosheets patchwork effectively covered even the smallest bumps and wrinkles on the mouses digits, and after the material dried, it clung in place.
When the researchers tested the nanosheets on burns, the dressing effectively kept out the common bacteria Pseudomonas aeruginosa. This species of pathogen often is a culprit in skin infections, and is notorious for causing hospital-acquired infections that can be deadly. Multi-drug resistant strains also can be problematic.
The dressing protected wounds from infection for three continuous days. With an additional coating, the nanosheets kept bacteria out for a total of six days. That means the material, if eventually approved for human patients, could cut down the number of times dressings have to be changed. With an eye toward human clinical trials, the researchers are planning large-scale animal tests and safety tests.
Okamuras group also has started developing a novel set of similar, highly flexible, patchwork coatings composed of polymers with a phosphorylcholine group. They have shown these materials are compatible with blood and could act as coatings for medical devices, such as catheters.