Chapel Hill, NC--Researchers from North Carolina State University have developed microneedles that can be used to deliver quantum dots into skin--an advance that opens the door to new techniques for diagnosing and treating a variety of medical conditions.
"We were able to fabricate hollow plastic microneedles using a laser-based rapid-prototyping approach," says Roger Narayan, one of the lead researchers. Narayan is a professor in the joint biomedical engineering department of North Carolina State's College of Engineering and the University of North Carolina at Chapel Hill.
Deeper layers of skin
"Our findings are significant in part because this technology will potentially enable researchers to deliver quantum dots, suspended in solution, to deeper layers of skin," says Narayan. "That could be useful for the diagnosis and treatment of skin cancers, among other conditions."
The researchers created the plastic microneedles and tested them using pig skin, which has characteristics closely resembling human skin. Using a water-based solution containing quantum dots, the researchers were able to capture images of the quantum dots entering the skin using multiphoton microscopy. The images showed the mechanism by which the quantum dots enter the layers of skin, allowing the researchers to verify the effectiveness of the microneedles as a delivery mechanism.
Two-photon polymerization
The microneedles were created using two-photon polymerization, an approach pioneered by North Carolina State and Laser Zentrum Hannover for use in medical-device applications. "Our use of this fabrication technology highlights its potential for other small-scale medical device applications," says Narayan.
A paper describing the study, "Multiphoton microscopy of transdermal quantum dot delivery using two photon polymerization-fabricated polymer microneedles," will be published in the September issue of Faraday Discussions. The work was funded by the National Science Foundation and the National Institutes of Health.
The research was co-authored by Nancy Monteiro-Riviere, professor of investigative dermatology and toxicology at North Carolina State's Center for Chemical Toxicology Research and Pharmacokinetics; North Carolina State Ph.D. students Shaun Gittard, Philip Miller and Ryan Boehm; Aleksandr Ovsianikov and Boris Chichkov of Laser Zentrum Hannover; and researchers from Ceramatec Inc. and MicroLin LLC & Technology Holding LLC.
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