A microneedle-based sensor puck designed by Sandia National Laboratories researchers to continuously monitor the levels of a ‘last line of defense’ antibiotic with less pain than a blood draw. (Credit: Craig Fritz)

Researchers have combined earlier work on painless microneedles with nanoscale sensors to create a wearable sensor patch capable of continuously monitoring the levels of certain antibiotics.

The sensor system starts with a commercially available microneedle. A polymer-coated gold wire about one-quarter the thickness of a human hair is soldered to a connector Reference and counter electrodes are constructed using coated silver and platinum wires inside commercial microneedles, respectively.

These needles are then inserted into a plastic patch. This patch includes room for nine microneedles but can be adjusted for any number desired. On the exposed, diagonal surface of each gold wire, the researchers chemically attach the nanoscale sensors.