A rapid and user-friendly assay to detect the Neutrophil gelatinase-associated lipocalin (NGAL) using up-converting nanoparticles

NGAL is a promising novel biomarker for acute kidney injury (AKI) and chronic kidney disease (CKD). More rapid and user-friendly methods are needed for the timely monitoring of NGAL in human urine and serum. UCP technology-based lateral flow assay (UPT-LFA) was developed for rapid, user-friendly and quantitative detection of the NGAL in human serum specimens and urine specimens. Under optimal conditions, the UPT-LFA displayed a rapid response to NGAL with a LOD of 7.68ng/mL and detection range from 7.68 to 1000ng/mL. The UPT-LFA method was compared with commercial immunoturbidimetry (103 urine specimens), and by ELISA (26 serum specimens), respectively. The results demonstrated that the UPT-LFA was consistent with immunoturbidimetry assay, reporting a 97.92% of positive and 92.73% of negative coincidence rates, respectively. Meanwhile, the concordance rate between UPT-LFA and ELISA, as shown by correlative regression analysis, was also high (R2=0.95). The whole assay can be completed within 30min compared to 4h consuming with ELISA. The research implies that, the UPT-LFA provides a potential to be used in point of care testing (POCT) to define early acute kidney injury with advantages of user-friendly and rapid testing, promising this new assay a bright future. Sandwich-based test strip assay format. [Display omitted] •An efficient and user-friendly solvothermal method for the synthesis of β-NaYF4:Yb, Er up-converting nanoparticles.•The fluorescence assay procedure is rapid, stable and relatively easy to use.•The assay can be completed within 30min compared to traditional ELISA which needs up to 4h.•The UPT-LFA assay correlated well with both the immune turbidimetric method and the ELISA assay.