Facile, Noninvasive, and Chemical-Free Hydrogen Peroxide and Glucose Detection Using a Fluorescent Cellulose Hybrid Film Embedded with PtRu/Carbon Dots

Diabetes affects over 8.8% of the global population, driving demand for noninvasive glucose detection methods. Traditional enzymatic assays are sensitive but face challenges such as high cost, complex preparation, low stability, and enzyme denaturation. This study aimed to enhance glucose detection sensitivity with a noninvasive easy-to-use technique using a fluorescent cellulose film. Lignin-derived carbon dots (LCDs) were synthesized as cost-effective, stable nanozymes for fluorescence-based glucose sensing. It was found that doping noble metal Ru onto Pt/LCDs synthesized in water mimicked peroxidase enzyme and could enhance the reactivity and sensitivity to ultralow levels for glucose detection at room temperature. To fabricate a wearable sensor, a transparent cellulose film embedded with PtRu/LCDs and glucose oxidase (GOx) was fabricated for biocompatible glucose sensing. The film achieved sensitive detection in the range of 0.05–1.0 mM (R² = 0.94) with a detection limit of 50 μM, suitable for noninvasive glucose detection in saliva, tears, and sweat. This study highlights the potential of the PtRu/LCD-based cellulose film for highly sensitive, wearable glucose sensors compatible with smartphone applications, offering a simple, real-time, noninvasive, fast, and chemical reagent-free glucose sensing for preventive healthcare.