A research team at North Carolina State University has created incredibly small microneedles to be used in the treatment of medical conditions by inserting nanoscale dyes called quantum dots into the skin. This new procedure could advance a doctor’s ability to diagnose and treat a variety of conditions, including skin cancer.

Microneedles are very small needles, where in one dimension, such as length or width, the size is less than one millimeter (0.04-inches). Dr. Roger Narayan, professor and leading researcher at North Carlonia State University explained, "The motivation for the study was to see whether we could use microneedles to deliver quantum dots into the skin. 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 went on to explain how the findings were remarkable since this new technology would enable doctors to insert quantum dots (within a solution) into deeper layers of the skin, thus proving a possible treatment for serious conditions such as melanoma. Quantum dots are nanoscale crystals with unique properties in terms of light emission and greatly assist with diagnosis.

The research team carried out tests on pig skin, which closely resembles human skin. Using plastic miscroneedles and a water-based solution with quantum dots the researchers inserted the solution into the pig skin and recorded the findings using a multiphoton microscope. By being able to watch the procedure the team could analyze the effectiveness of the microneedles in delivering quantum dots.

The study also illustrated that a laser-based rapid prototyping approach provides for the manufacture of microneedles of varying lengths and shapes. This could allow surgeons to create customized microneedles specific for the treatment of a particular condition. By creating microneedles using two-photon polymerization, an approach pioneered by NC State and Laser Zentrum Hannover for use in medical device applications, allowed the researchers to create specifically purpose-designed microneedles. "Our use of this fabrication technology highlights its potential for other small-scale medical device applications," Narayan says.

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.