By Marti MaGuire
Dr. Roger Narayan is trying to take the bite out of one of medicine's most common and reviled procedures: the shot.
Based at N.C. State University, Narayan's research aims to replace those unpleasant jabs with patches lined with microneedles - microscopic points so tiny they enter the skin with almost no pain.
Microneedle technology has existed in the lab for a decade, but its entry into doctors' offices, clinics and hospitals has been stymied by fears of infection and limitations on the shape of the needles.
"If it could be used, it could provide a faster, less painful way to do a shot," said Narayan, a professor in the joint biomedical engineering department of NCSU's College of Engineering and the medical school at UNC-Chapel Hill.
Narayan, who is both a medical doctor and Ph.D. in engineering, has worked with other researchers to pioneer the use of laser technology to make microneedles, solving many of the structural problems that hindered earlier research.
Among the most important innovations was to make the tiny needles hollow so they could inject medicine and test blood. Another was to add antimicrobial agents to the needles to ward off infection.
Dr. Harold Pillsbury, a UNC-CH surgeon who has worked withNarayan on several projects, said the widespread use of microneedles is eagerly anticipated in medical circles.
"I think this is going to be the new way we do a lot of things," said Pillsbury, chairman of the head and neck surgery department at UNC-CH.
The appeal of microneedles goes well beyond escaping the sting of a conventional shot. The less invasive delivery method could save time and doctor visits, particularly for chronically ill patients.
The tiny needles could also help doctors target medications more accurately.
"It allows us to deliver medications in very small doses to very specific areas of the body," Pillsbury said. "Right now, if I give a patient something for their ear, I have to give it to their whole body. If I can give it just to the ear, I can give smaller doses and minimize side effects."
The first to benefit would likely be patients with chronic diseases:
Cancer patients, for instance, could wear a band lined with microneedles that would periodically test their blood and then administer tiny doses of medicine based on the results.
A similar delivery system could be used for patients battling drug addictions.
Mass immunizations could be done using patches instead of needles, saving doctors time and patients pain.
Different lengths of microneedles could target different layers of skin, which could be useful for treating skin cancer.
"Not only are you getting a time savings in reduced interaction with the provider, but you're actually getting a better result in the end, a more targeted approach," Narayan said.
Making minuscule needles
Narayan and his team borrowed a process known as two-photon polymerization, which is used to make parts for electronics and telecommunications devices. Using this technique, needles are formed according to a computer blueprint by lasers that selectively harden liquid polymers on a motorized platform.
Other methods have been used to create medical devices as small as 50 micrometers, a unit of measure equivalent to 1millionth of a meter. With this technology, Narayan can make objects as small as 200 nanometers, or 1billionth of a meter.
The head of a pin, in comparison, measures about a million nanometers across.
The process also allows Narayan to make intricate microscopic shapes one at a time. Earlier methods of making microneedles, which are similar to the way computer chips are made, require creating an expensive and time-consuming model for each shape.
"This offers a significant amount of greater flexibility in design," Narayan said.
A tiny Statue of Liberty
The ease with which he can make these shapes has led Narayan to experiment with other uses for the laser technology - fashioning implants to fit a particular patient's ear precisely, for instance. He is even working with UNC-CH art students on a microscopic Statue of Liberty for a National Science Foundation competition.
After working with microneedles for years, Narayan has benefited from a recent spike in interest. He has published 20 academic papers on microneedles and related topics in the past year.
He is also part of several research groups studying various aspects of microneedles, using funding from the National Institutes of Health and other sources.
"We're essentially trying to find the best applications for this technology in the medical sphere, the ones that have the greatest match between the capability of the technology and clinical needs," Narayan said.