Patches Provide Painless Drug Testing

Microneedles on a sticking-plaster-like patch could provide a painless and safer way to test for drugs and some infections in the future, following work carried out at Queen’s School of Pharmacy where samples of the rough, absorbent patches are being tested by award-winning researcher, Dr Ryan Donnelly.

The experiments, which received funding from the Engineering and Physical Sciences Research Council (EPSRC) are showing that the forest of tiny polymer needles on the underside of the patch, originally developed for injecting pre-loaded vaccine or drug compounds into the skin, can also be developed to absorb targeted fluids and other biological fluids from surface tissue.

“The important thing is that we typically find the same compounds in this interstitial fluid as you would find in the blood,” Dr Donnelly explains. “But, compared with drawing blood, our patches can get their samples in a minimally invasive way. And it’s far safer than using a conventional needle. These microneedles, once they have been used, become softened, so that there’s no danger of dirty needles transferring infection to another patient, or one of the healthcare workers. Two million healthcare workers are infected by needlestick injuries every year.”

Real-time monitoring could be a realistic option in the future possibly by combining the microneedle technology with simple laser-based detection (“SERS”) of drug compounds inside the gel. The Queen’s University Belfast group already has proof-of-concept for this idea and have been looking to extend the range of drug concentrations that can be detected in this manner. Electrochemical detection is another attractive possibility that might allow patients to use the technology in their own homes with medicine levels adjusted according to the microneedle readings, both enhancing patient care and saving NHS resources.