Microneedle Drug Monitoring System May Improve Patient Care

A microneedle drug monitoring system that does not pierce the skin like a standard hypodermic needle was developed by researchers at the University of British Columbia (UBC) and the Paul Scherrer Institut (PSI).

This new system is made of a small, thin patch that is pressed against a patient’s arm during medical treatment to measure drugs in the blood. The tiny needle-like projection is less than half a millimeter long, and resembles a hollow cone.

Microneedles are designed to puncture the outer layer of skin, but not the epidermis and the dermis.

“Many groups are researching microneedle technology for painless vaccines and drug delivery,” said researcher Sahan Ranamukhaarachchi, developer of the technology. “Using them to painlessly monitor drugs is a newer idea.”

Ranamukhaarachchi and his team decided to create this technology to monitor the antibiotic vancomycin, which is administered through an intravenous line. Those who take the antibiotic must undergo 3 to 4 blood draws per day, while also being closely monitored because the antibiotic can have life-threatening side effects.

“The combination of knowhow from UBC and PSI, bringing together microneedles, microfluidics, optics and biotechnology, allowed us to create such a device capable of both collecting the fluid and performing the analysis in one device," said Victor Cadarso, a research scientist and Ambizione Fellow at PSI.

Researchers discovered that the fluid just below the outer layer of skin could be used instead of blood to monitor the levels of vancomycin in the blood. The microneedle collects less than a millionth of a milliliter of the fluid, and a reaction occurs inside of the microneedle that researchers are able to detect using an optical sensor.

This approach allows researchers to determine the concentration of vancomycin both quickly and easily.

“This is probably one of the smallest probe volumes ever recorded for a medically relevant analysis," said Urs Hafeli, associate professor in UBC's faculty of pharmaceutical sciences.