The antibiotic vancomycin is used to treat serious infections, but it can cause life-threatening toxic side effects. An intravenous line is used to administer vancomycin and three to four blood draws per day are required for monitoring. As you can imagine, this is not a pleasant experience.
Different microneedle technologies are being researched by many groups for painless vaccines and drug delivery systems, but Sahan Ranamukhaarachchi, a PhD student in UBC‘s faculties of applied science and pharmaceutical sciences, developed this technology to monitor drugs painlessly, specifically vancomycin.
But this new microneedle delivery system comes as a thin, small patch that is pressed against a patient’s arm during medical treatment. The patch contains a tiny needle-like projection that painlessly measures drugs in the bloodstream without drawing any blood. The needle resembles a hollow cone and is less than half a millimeter long. Unlike a standard hypodermic needle, it doesn’t pierce the skin.
Microneedles only puncture the protective shield provided by the outer layer of skin. The epidermis and the dermis, which house active immune cells, nerves and blood vessels are not touched. Ranamukhaarachchi and his colleagues discovered that they could monitor levels of vancomycin in the bloodstream by using the fluid found just below the outer layer of skin. At the time, Ranamukhaarachchi was on a research exchange at the Paul Scherrer Institut (PSI) in Switzerland.
This technique means that no blood has to be drawn for the analysis. Researchers can determine the concentration of vancomycin quickly and easily by using less than a millionth of a milliliter of this fluid collected by the microneedle. The fluid causes a reaction on the inside of the microneedle. Researchers can then detect this reaction using an optical sensor.
Urs Hafeli, associate professor in UBC’s faculty of pharmaceutical sciences, notes that this medically relevant analysis was done with one of the smallest probe volumes ever recorded.
The creation of a device capable of both collecting the fluid and performing the analysis was enabled by bringing together optics, biotechnology, microneedles and microfluidics. The combined knowhow from UBC and PSI has resulted in the creation of a microneedle drug monitoring system that will improve patient comfort and replace invasive, costly blood draws.