A 3D-printed dual-mode gel microspheres kit for multipath smart detection of multiple targets in urine

Accurate and timely detection of ions and metabolites in urine is essential for health monitoring. However, traditional methods face challenges in integrating multiplexity, signal stability, and portability. To address these issues, this study developed a 3D-printed portable dual-mode gel microspheres kit. The hydrogel microspheres were prepared by encapsulating the respective indicators: Urine pH Indicator (UpHI) for pH detection, Urine Calcium Ion Indicator (UCaI) for Ca 2+ detection, and Urine Creatinine Indicator (UCrI) for creatinine detection. Each indicator was optimized for its specific target to ensure high sensitivity and selectivity. The system employs dual-mode UV and visible light analysis, combined with smartphone imaging and RGB data processing, ensuring rapid, intelligent, and high-throughput detection. The integration of gel microspheres with a 3D-printed microdevice enhances the portability and user-friendliness of the detection system. This design facilitates long-term storage and transportation while ensuring usability for non-technical individuals in home settings. The kit demonstrated excellent encoding capacity, maintained stable signals for up to a week, and achieved integrated detection, data acquisition, and analysis within approximately 6 min. The cost per microsphere is under $0.20, making it a cost-effective solution. In conclusion, this method offers an effective solution for portable and timely urine health monitoring in home settings and provides a promising approach for the future development of portable kits with expanded detection pathways.