A portable photobleaching-resistant photothermal sensor for high-sensitivity and on-site biomarker detection

The development of sensing technology has led to significant advancements in sensors crucial for human health, environmental protection, and food safety. However, traditional signal acquisition methods are often high-cost and complex, limiting their application in resource-poor settings. In this study, we developed a photobleaching-resistant photothermal sensor utilizing a paper-supported gold nanozyme system. By integrating miniaturized infrared detectors, microcontroller boards, and smartphones, we achieved a portable and highly functional photothermal sensing platform. An RGB chip was incorporated into the device to monitor and mitigate photobleaching, thereby increasing the sensor’s accuracy. Moreover, the system stabilized gold nanoparticles, preventing aggregation, and enhanced sensor performance by facilitating rapid catalytic disengagement, reducing interference from the experimental environment. Our sensor demonstrated real-time, in situ detection with a limit of detection (LoD) of 4.83 μM for glucose in human saliva and a LoD of 0.23 µM for ascorbic acid in beverages, across wide dynamic ranges of 5–150 μM and 1–100 μM, respectively. This approach also exhibited excellent stability and reproducibility. The developed sensing platform offers broad prospects for widespread applications in healthcare, environmental monitoring, and food safety, presenting practical solutions to the challenges of deploying sensitive, efficient, and cost-effective detection technologies.