Search

In this paper, a simple, rapid and high-throughput fluorescence polarization immunoassay (FPIA) based on polyclonal antibodies (PAb) is described for the determination of glycocholic acid (GCA) in human urine. Three fluorescein-labeled GCA (tracers) with different structures and spacer bridges were synthesized and purified by thin-layer chromatography (TLC). The structure effect of tracers on the assay was investigated and the sensitivity of best tracer in the optimized FPIA demonstrated an IC 50 value of 306 ng/mL. The working range of FPIA was 36 ∼ 2 600 ng/mL and the limit of detection (LOD) was 9 ng/mL. The developed FPIA was time-saving that could be completed within 10 min. Human urine samples spiked with GCA were analyzed by this method, followed by confirmation with commercial enzyme immunoassay analysis (EIA). Excellent recoveries and correlation between these two methods were observed (R 2  = 0.996), suggesting the developed FPIA could be applied to screening of GCA in human urine samples without complicated cleanup., (Copyright © 2018. Published by Elsevier B.V.)

To develop a sensitive fluorescence polarization immunoassay (FPIA) for detecting Diisobutyl phthalate (DIBP) in Yoghurt. Five tracers with different lengths of bridge between the hapten molecule and fluorescein isothiocyanate (FITC), fluoresceinthiocarbamyl ethylenediamine (EDF), fluoresceinthiocarbamyl hexylenediamine (HDF), were synthesized and their respective binding responses with anti-DIBP-specific antibody were evaluated. The physicochemical parameters were optimised for the FPIA. The FITC-labelled DIBP conjugate (DIBP-FITC) was found to be the optimal tracer for FPIA of Diisobutyl phthalate. The detection limit of DIBP, IC50 value and the working range were 0.82, 9.32 and 1.16–74.97 ng/mL, respectively; and the reaction time was only 5min. The average recovery from spiked Yoghurt samples was 77.80–115.60% which showed good reproducibility for FPIA. Thus, the developed FPIA method exhibited the potential for the rapid and accurate determination of DIBP in agricultural and environmental samples. Image 1 • A Fluorescence Polarization Immunoassay method to quantify Diisobutyl phthalate in Yoghurt samples. • The methods could be selectively used for rapid screening of Diisobutyl phthalate in Yoghurt. • The new method has some referential significance for the control the content of plasticizer in food. • The method was suitable for daily test of a large number of samples. [ABSTRACT FROM AUTHOR]

Trace concentrations of cholyglycine acid (CG) are useful to reflect the damage degree in liver cells, and useful in the diagnosis and prognosis of liver diseases. Therefore, developing an effective strategy to detect the concentration of CG is of great importance. A homogeneous fluorescence polarization immunoassay (FPIA) was developed for determination of CG concentrations. The effects of tracer concentration, antibody dilution and incubation time on FPIA performance were studied. The FPIA was used to detect CG in sera from 522 patients with liver diseases and 449 healthy controls. The results were compared with those obtained through enzyme multiplied immunoassay technique (EMIT). The FPIA showed a detection limit of 50.9 ng/mL for CG and the cross-reactivity of antibodies with nine structurally and functionally related analogs were negligible. Concentrations of CG in patients with chronic hepatitis B virus, liver cirrhosis and decompensated cirrhosis were 5.4, 7.9 and 6.5-fold higher than those in controls, respectively, and hence were significantly different from controls (P < 0.001). The FPIA developed in this study is a rapid, convenient, and simple method, suitable to be used as a screening tool for homogeneous detection of CG in serum. The detection results of FPIA demonstrate that concentrations of CG were much higher in liver patients than in controls. Therefore, CG may be a good biomarker for the diagnosis of liver diseases. [ABSTRACT FROM AUTHOR]