A couple of months ago, we covered a microneedle antimicrobial technology developed by researchers at North Carolina State University. Now, researchers at that university have developed microneedles that can be used to deliver medical nanoscale dyes to the skin. Composed of nanoscale crystals featuring unique light-emission properties, the quantum-dot based dyes are could be used in conjunction with microneedles to diagnose and treat various medical conditions, including skin cancer.
In these tests, the microneedles were created using two-photon polymerisation, an approach pioneered by North Carolina State University and Laser Zentrum Hannover for use in medical device applications. Two-photon polymerisation allowed the researchers to create hollow, plastic microneedles with specific design characteristics. “Our use of this fabrication technology highlights its potential for other small-scale medical device applications,” explains Roger Narayan, a lead reseracher on this project and a professor at the University of North Carolina.
After creating the plastic microneedles, the researchers tested them using pig 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 on this page show the mechanism the quantum dots use to enter the layers of skin, allowing the researchers to verify the effectiveness of the microneedles as a delivery mechanism for these nanoscale dyes.
“We were able to fabricate hollow, plastic microneedles using a laser-based rapid prototyping approach and found that we could deliver a solution containing quantum dots using these microneedles,” Narayan says. “The motivation for the study was to see whether we could use microneedles to deliver quantum dots into the 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. That could be useful for the diagnosis and treatment of skin cancers, among other conditions.”
The study also shows that a laser-based rapid prototyping approach enables the creation of microneedles of varying lengths and shapes. This will allow medical device manufacturers to create microneedles that are customised for treatment of specific conditions.Brian Buntz