A bite from a tiny sand fly can cause big health problems for people in Third World countries, including U.S. troops in Iraq. The parasites can carry and transmit leishmaniasis, which in its most common form leaves slow-healing lesions on the skin.
Now, scientists from the University of Akron (Akron, Ohio) are hoping to speed the healing of these wounds with the development of nanofiber bandages.
“Through the use of electro-spun nanofibers, wounds that took months or years to heal are now showing improvement in weeks,“ said University of Akron chemistry professor Daniel Smith, PhD.
“The dressing in itself is a very exciting medical device,“ Smith told Medical Device Daily. “But what we wanted to do was to combine that dressing with a means of delivering nitric oxide [which kills the parasite, reduces inflammation and promotes the vascular flow of oxygen] because we know that a large group of people in the world have parasitic infections.“
Because the parasite in cutaneous leishmaniasis — the most common form of the disease — lives in the wound, the infected person's immune system does not function normally, and the open wounds on the skin can persist for months, leaving unsightly scars.
“Those cells normally would produce nitric oxide, which would kill the parasite and allow for normal healing,“ Smith said. “So the logic is, if you introduce into the wound something that would normally be made by humans, the drug nitric oxide added to the wound would then promote the destruction of the parasite and therefore bring the wound back to normal.“
With the help of Darrell Reneker, PhD, professor of polymer science at the university, Smith designed a highly elastic, superabsorbant 2“ x 2“ dressing made of nanofibers.
A simple design and ease of use is key to the bandage, Smith noted, because it is used in the field or jungle, where the patch is wetted with sterile water to start the chemistry for nitric oxide release, and applied to patients on a daily basis.
The nanofiber bandages are currently being studied in Bolivia and Columbia, where the University of Akron is collaborating with the Colombian Cardiovascular Foundation (Bucaramanga, Columbia) on Phase II clinical trials. The double-blind clinical trial is testing the nanofiber bandages on between 900 to 1,000 people with cutaneous leishmaniasis, Smith said.
He pointed again to the simple design and the just-add-water mechanism of the bandage for ease-of-use in the field — which isn't always a hospital. “We try to keep [our] design very simple because we're taking these out into the jungle where humidity and temperature are extremely high, so we can't take a drug out there that is extremely sensitive to temperature or has to be refrigerated,“ he said.
Smith said the trial is looking at several endpoints, including the dressing's usefulness, tolerability, ergonomic aspects and the effects of nitric oxide to promote the healing process.
“Fortunately, what we are learning is [the dressing] turns out to be extremely beneficial, that we're getting wound closure that the attending physicians say is looking extremely good,“ he said.
The Phase II trials will conclude in about six months, Smith said. If successful, a Phase III trial to obtain FDA approval for use of the technology in the U.S. to treat other types of wounds will follow.
Smith estimates leishmaniasis affects 12 million to 15 million people worldwide. Though it is not found in America, U.S. troops serving in Iraq are facing the largest outbreak of leishmaniasis among military personnel since World War II, according to Defense Department doctors.
“The military has interest in this,“ Smith said, noting that it is studying other drug candidates and even vaccines. “So there are some competing technologies,“ he said, adding that many are temperature-sensitive, an area where nanofiber bandages have an advantage.
Using the nanotechnology bandage as a preventive measure is a future goal, Smith said. “If our technology was so that we could actually put this directly on the bite itself, and we could catch it at that point, then it would be very beneficial, and likewise with the full lesions.“
The university has applied for a grant from the National Institutes of Health (Bethesda, Maryland) to look into various Third World disease states. Smith said private sources of funding may also be explored.
The bandages are inexpensive to produce, and Smith said the intention is that countries will use the university's patented technology to produce these dressings for their own society's needs, “just as a goodwill gesture.“
“There is really no financial gain by treating Third World parasitic lesions. That's not a money-making proposition, even though it affects a lot of individuals,“ he said. “What we benefit out of this is there are a lot of other types of wounds in the world, a lot of them affecting First and Second World countries.“
“What we see is a carryover of this technology to other types of wounds,“ Smith said, particularly in slow-healing wound situations such as ulcers, or the treatment of acne or warts.