Don’t sweat it: laser-induced graphene monitors analytes in sweat

Collecting blood provides important information about concentrations of drugs and biomarkers in modern medicine, but the process is invasive and requires trained personnel. Other biological fluids, such as sweat, tears, and saliva, present a possible noninvasive alternative for monitoring health.

Vivaldi et al. created a sweat sensor using laser-induced graphene (LIG), a relatively new porous and conductive material. The device was fabricated with laser-induced pyrolysis, which is low-cost, fast, and allows for quick prototyping and customization. Conductive tracks are drawn on insulating polymers without using masks or additional chemicals. The simple process can be scaled for large scale production.

For athletes, the sweat sensor could become a useful tool for monitoring performance. By measuring uric acid, tyrosine, conductivity, and pH, it provides insight on the subject’s physical condition.

“Uric acid is related to the oxidative stress inside the body. Tyrosine is related to the kidney’s efficiency,” said author Federico Vivaldi. “Conductivity gives information about the hydration status, while pH can be used as a parameter for the overall status of the subject.”

Modifying the surface of the LIG electrodes to include other sensing chemicals would allow the sensor to monitor more components of sweat.

“We hope that the development of LIG-based devices will come to a level where measurement of sweat — or other liquids — on skin can be used for the monitoring of diseases, for example,” said author Alexander Dallinger.

While LIG includes many important properties for chemical sensing, not all the processes related to laser parameters and the resulting structures are known. The authors plan to investigate the interactions between the material and analytes and their impacts on sensing performance.

Source: “Sweat analysis with a wearable sensing platform based on laser-induced graphene,” by F. Maria Vivaldi, A. Dallinger, N. Poma, A. Bonini, D. Biagini, P. Salvo, F. Borghi, A. Tavanti, F. Greco, and F. Di Francesco, APL Bioengineering (2022). The article can be accessed at https://doi.org/10.1063/5.0093301 .

This paper is part of the Emerging Technologies in Wearable Sensors Collection, learn more here .