Gao_2025_Anal.Chim.Acta_1379_344729

Urinary tract infection (UTI) is a significant global health issue. Urine bacterial culture is time-consuming, prone to misdiagnosis, and the existing sample pretreatment methods are cumbersome, relying on centralized laboratories and specialized equipment. Colorimetric sensing provides a faster alternative. However, its accuracy is often compromised by the variable color of the patient's urine samples. Therefore, it is clear that a rapid, simple, gentle, and environmentally friendly pretreatment method is needed that effectively eliminates color interference in colorimetric detection and is compatible with smartphones, enabling real-time, quantitative on-site monitoring of UTI. (90) RESULTS: In this study, we describe a unique smartphone-assisted diagnostic method for quantifying nitrite, leukocyte esterase (LE), and bacteria in urine samples. The method employs activated carbon composite hydrogel spheres for urine pretreatment, which effectively removes background color interference and improves sensor performance, and combined with a smartphone-based microplate analyzer independently developed by our group previously, allows for precise colorimetric examination. This will aid in the prompt detection and dynamic monitoring of urinary tract infections in clinical settings. Furthermore, the bacterial detection time was shortened to 2 h, enhancing the accuracy and timeliness of the diagnostic process. The detection limits of nitrite, LE, and E. coli were 0.0584 mg L(-)(1), 0.0775 Leu microL(-)(1), and 2.94 CFU mL(-)(1), respectively, meeting clinical requirements. Validation of 147 clinical samples indicated high consistency with the Sysmex UC-3500 Automatic Urine Analyzer, demonstrating the sensor's durability and accuracy. (141) SIGNIFICANCE: Activated carbon hydrogel beads with high adsorption properties were used for the pretreatment of urine samples for the first time, effectively removing background color interference in colorimetric detection. Integration of a smartphone-based microplate analyzer with a hydrogel slow-release system enables quantitative detection of nitrite, LE, and bacteria. This strategy offers a portable, low-cost solution for home-based UTI monitoring, enabling more timely management and appropriate administration of therapy to improve patient outcomes. (71).