Reading Blood Glucose from Sweat... Next-Generation Laser-Patterned Sensor [Reading Science]

KITECH and Hanyang University Develop Non-Invasive Blood Glucose Sensor Technology Without Mask Process

A Korean research team has developed a non-invasive blood glucose sensor manufacturing technology that can reduce the inconvenience of diabetes patients having to prick their fingers several times a day for blood glucose measurement. The key feature is that the electrodes are formed using only a laser, eliminating complex mask processes and achieving both high sensitivity and high durability at the same time.

The joint research team from the Korea Institute of Industrial Technology (Saenggiwon) and Hanyang University announced on the 11th that they have developed a non-enzymatic glucose sensor technology that can be fabricated solely through laser patterning without any mask process. This technology was designed with an eye toward application in wearable sensors that measure blood glucose using sweat.

Flexible sweat glucose sensor fabricated by a laser process. Provided by Saenggiwon

Conventional non-invasive blood glucose sensors require multiple steps such as mask fabrication, exposure, and etching to produce electrodes, and they have the limitation that any design change requires restarting the entire process from the beginning. In addition, enzyme-based sensors are vulnerable to heat and light, causing performance degradation when used over long periods.

To overcome these constraints, the research team applied a patterning technology that directly draws the electrode geometry with a laser. They irradiated a plastic substrate containing tin oxide (SnO₂) nanoparticles with a laser to activate the surface, then immersed it in a copper solution so that copper was selectively deposited only on the laser-irradiated regions. Nickel and gold were subsequently coated in sequence to complete a triple-protection-structure electrode.

The fine concave-convex microstructure formed by laser irradiation increased the contact area with glucose and enhanced detection performance, while also allowing application to flexible plastic substrates without high-temperature treatment or vacuum equipment. Electrode design changes can also be made simply by modifying the laser path on a computer, greatly improving manufacturing flexibility.

The research team implemented a non-enzymatic sensor by applying a metal-catalyst-based sensing layer instead of enzymes on top of the electrode. By coating a platinum (Pt) and carbon composite so that it directly reacts with glucose in sweat, they completed a structure that can be integrated with the laser process.

Performance evaluation showed that the glucose detection sensitivity of the developed sensor is about 18 times higher than that of commercial electrodes. Even after 100,000 bending cycles under a bending radius of 5 mm, changes in electrical performance remained within the durability standards for wearable sensors.

This technology is expected to have strong potential not only for non-invasive diabetes monitoring but also for broader application across wearable healthcare devices that require long-term wear. By simplifying the process, it can reduce manufacturing costs and thus offers competitiveness in terms of commercialization.

Chanwoo Yang, principal researcher at the Korea Institute of Industrial Technology, who led the study, said, "We have implemented a high-sensitivity, high-durability sweat glucose sensor using only a laser without any mask process," adding, "We plan to further develop it into a non-invasive diabetes monitoring and wearable healthcare platform."

This achievement was carried out with support from the flagship project in the root-technology field at the Korea Institute of Industrial Technology and the Mid-career Researcher Program (Creative Research type) of the National Research Foundation of Korea. The research results were published last December in ACS Applied Bio Materials, an international journal in the field of biomaterials and sensors.

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