Laser Surface Micromachining-Based PVC Diffusion Layer for Multimodal Wearable Sports Sensors

Abstract

Multimodal wearable sports sensors capable of simultaneously detecting both physical and biochemical signals represent a transformative approach to comprehensive physiological monitoring during exercise. However, most existing systems either focus solely on physical parameters or suffer from limited sensitivity and sensing range when targeting high-concentration biochemical markers. There remains a challenge for integrated platforms that can robustly monitor metabolic status in realistic sports scenarios. This work presents M-SportSense, an integrated wearable platform for real-time multimodal sweat analysis that combines lactate and pH sensing. The core innovation is a laser surface micromachined PVC diffusion layer that dramatically enhances lactate detection performance. By employing a 1064 nm laser to create a circular hole array on the honeycomb PVC surface, the detection range is expanded by 100 times while simultaneously increasing sensitivity by 127%. The M-SportSense integrates laser-induced graphene (LIG) electrodes functionalized with lactate oxidase for lactate sensing, polyaniline for pH sensing, and serpentine LIG for temperature monitoring. A three-layer microfluidic device with optimized inlet design ensures efficient sweat collection and rapid refreshing rates. On-body validation during 20-min indoor cycling demonstrates stable multimodal detection of sweat lactate and pH, validating the platform's potential for personalized exercise monitoring, fatigue assessment, and real-time training optimization.