How microneedle sensors could watch your blood chemistry

Patches of tiny needles have already been shown to effectively deliver medications painlessly, and without a bloody mess. Now the tiny needles could also be used to monitor body chemistry in real time.

The new tech, developed by a team of biomedical engineers out of North Carolina State University, the University of California at San Diego, and Sandia National Laboratories, employs electrochemical sensors in the hollow channels of microneedles to detect certain molecules. The researchers reported their findings in the chemistry journal Talanta.

Current body chemistry monitoring involves taking samples, often before or after an event. Wearable micro-sensors, on the other hand, could monitor a diabetic's glucose levels in real time to help scientists explore precisely what causes high or low levels, or to warn the user as levels rise or fall.

Customized microneedle sensor arrays could be incorporated into wearable devices such as wristwatches, says Roger Narayan, a biomedical engineering professor at North Carolina State.

The team's proof-of-concept array uses three sensors to measure acidity (pH), glucose, and lactate, but Narayan says other sensors will likely be developed to measure a wider range of molecules.

"Microneedle-based sensors could be used to monitor a variety of physiologically-relevant molecules," Narayan says. "For example ... [to detect] glutamate, an excitatory neurotransmitter."

And because the needles are so small, you might be able to wear such a sensor safely and comfortably even in the middle of strenuous activities. For instance, it could measure lactate levels (which can indicate exertion) in athletes, soldiers, or the elderly.

Narayan says the team's next steps will include testing these devices in a variety of settings.