A portable hydrogel kit coupled with smartphone for point-of-care glucose testing

Glucose monitoring is a critical aspect of healthcare, particularly for the clinical diagnosis and ongoing management of diabetes mellitus. However, existing glucose assays still encounter problems such as time-consuming procedures, operational complexity, and reliance on specialized equipment. Our study introduced an innovative point-of-care testing (POCT) platform for one-step glucose detection that integrated a hydrogel kit with a nanozyme-based cascade reaction, which provides significant signal amplification for high sensitivity, and smartphone technology. The nNO 2 -MIL-101-Fe (Fe-MOF), synthesized using the electron-withdrawing ligand 2-nitroterephthalic acid, exhibited catalytic activity comparable to that of enzymes. When glucose oxidase (GOx) was immobilized onto this material, it formed a cascade catalytic system that stabilized enzymes and minimized the diffusion resistance of intermediates. The hydrogel, in its moldable form, acted as a carrier and improved enzyme stability due to its hydrophilic environment. In the cascade catalysis process, glucose from the sample triggered a reaction that converted 3,3′,5,5′-Tetramethylbenzidine (TMB) into a blue product, enabling a direct visual readout using a smartphone. Consequently, this portable POCT platform demonstrated high sensitivity and selectivity for glucose detection with a linear ranging from 0.05 to 1 mM and a detection limit of 0.035 mM. Validation in human serum samples confirmed its excellent accuracy, with recoveries ranging from 95.7 % to 101.6 %. The portable hydrogel kit-based POCT platform has the potential to significantly enhance diabetes management by providing a cost-effective, user-friendly, and accessible glucose monitoring solution.