Wearable fitness devices have become capable of achieving ever greater feats in recent years, but one of the more interesting comes via a stretchy patch that was recently developed by a team from King Abdullah University of Science and Technology in Saudi Arabia, which is capable of analyzing our sweat as we exercise.

The work, which was documented in a recently published paper, scours our sweat for a range of organic molecules, such as glucose and lactic acid, which are reliable markers for a range of health indicators.  The patch sits on the skin and directs our sweat towards electrodes that are coated in enzymes.  These enzymes allow the sensors to then electrically detect low concentrations of various compounds.

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One of the traditional challenges faced by such technologies is that enzyme biosensors can have a short lifespan as our skin can remove the enzyme layer from the biosensor relatively quickly.  The team believe they’ve overcome this by using a graphene like technology known as MXene, which is a flat ceramic that contains a combination of carbon and titanium atoms.  The conductivity and low toxicity levels of this material make it ideal for the job.

The team went on to attach minute dye nanoparticles to the MXene in order to increase its sensitivity to hydrogen peroxide, which is known to be the main by-product of the enzymes catalyzed in our sweat.  The MXene was then placed inside carbon nanotube filters for protection, before being placed onto a membrane that was designed o draw sweat through the pooling.

The electrodes are designed to ensure they can easily be swapped in and out of a polymer patch that both absorbs our sweat and then transmits the signals recorded to an external source, such as a smartphone.  The device was tested on volunteers as they rode an indoor bicycle, and the readings did indeed come through as expected as the workout progressed.

“We are working with KAUST and international collaborators under the umbrella of the Sensors Initiative to integrate tiny electrical generators into the patch,” the researchers explain. “This will enable the patch to create its own power for personalized health monitoring.”

You can learn more about the technology via the video below.