Flexible hydrophilic-hydrophobic array detection patch integrated with Au NPs/Cu-TCPP(Fe) biomimetic cascade...

The detection and quantification of glucose in human biofluids are critical for the early diagnosis and management of metabolic disorders such as hypoglycemia and diabetes. Non-invasive wearable sensors for sweat glucose monitoring have emerged as promising alternatives to traditional blood glucose testing due to their ease of use, rapid response, and portability. However, the development of stable, cost-effective, and enzyme-free wearable platforms capable of reliable sweat glucose detection remains a significant challenge. Current enzyme-based sensors often suffer from poor stability under ambient conditions, complex fabrication processes, and high costs, limiting their widespread applicability in resource-constrained settings.

Au NPs/Cu-TCPP(Fe) nanozymes exhibiting dual peroxidase-like and glucose oxidase-like catalytic activities were synthesized and characterized. These nanozymes catalyze a cascade reaction: glucose oxidation generates H₂O₂, which is then decomposed to produce hydroxyl radicals that oxidize 3,3',5,5'-tetramethylbenzidine (TMB), yielding a blue-colored product for colorimetric detection. A flexible, multi-layer hydrophilic-hydrophobic array patch was fabricated by integrating the nanozymes and TMB into a paper-based matrix. This design enables efficient in situ sweat collection, concentration, and colorimetric analysis. The patch exhibits a linear detection range of 20-200 μM with a detection limit of 12.72 μM, suitable for physiological sweat glucose levels. Selectivity tests confirmed negligible interference from common sweat components. A smartphone application was developed to enable real-time, quantitative analysis of colorimetric signals. Clinical validation on multiple volunteers across different skin locations (chest, back, forearm, forehead) showed strong correlation with reference methods (HPLC-MS, commercial glucose detection kit), with relative errors <10 %.

This study presents a low-cost and enzyme-free sweat glucose detection platform based on Au NPs/Cu-TCPP(Fe) nanozymes. The integration of smartphone technology enables point-of-care testing, making the platform particularly suitable for personalized health monitoring. The successful validation in human subjects demonstrates its potential for real-world applications in diabetes management and early disease detection. This work bridges the gap between nanozyme catalysis and wearable sensor technology, providing a versatile platform for non-invasive biomarker detection.