Si@D(AuPt) nanozyme-driven point-of-care testing technology for real-time monitoring of clinical urinary-related indicators

Abstract

To address the challenges of poor system compatibility, low sensitivity, and narrow detection range in traditional colorimetric lateral flow immunochromatographic assay (LFA) for dynamic monitoring of urinary tract infection (UTI) pathogens (biomacromolecules) and antibiotics (small molecules), we propose a colorimetric-enhanced LFA technique based on monodisperse bimetallic composite nanozymes (Si@D(AuPt)), achieving rapid and precise detection of different types of markers in real urinary tract infection samples. The raspberry-like Si@D(AuPt) nanozyme employs a highly stable SiO₂ core, with continuous loading of double-layer dense AuPt nanoparticles to provide rough surface area and dense spatial catalytic sites, greatly enhancing the complex sample stability and peroxidase activity of single nanolabel. Furthermore, efficient and stable antibody-nanomaterial coupling was achieved through 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB) molecule mediation, improving the universal detection capability and accuracy of the LFA system. Experimental results show that the platform achieves detection Limits of 11.64 cells/mL for Pseudomonas aeruginosa (sandwich mode), 6.70 pg/mL for gentamicin, and 3.69 pg/mL for cefalexin (competitive mode), with sensitivity at least 400 times higher than traditional colloidal AuNP-based LFA strips. Additionally, the proposed assay demonstrates excellent stability, sensitivity, and specificity in actual urine samples, providing a reliable technical means for real-time monitoring of UTI related indicators.

Graphical Abstract