Comparison of two fluorescence quantitative immunochromatographic assays for the detection of amantadine in chicken muscle.

The two sensitive fluorescence quantitative immunochromatographic assays (FQICAs), background fluorescence quenching immunochromatographic assay (bFQICA) and time-resolved fluorescent immunochromatographic assay (TRFICA), play an important role increasingly in rapid detection technology for food safety. Amantadine (AMD), used extensively in virus infections in livestock and poultry, has been prohibited due to hazard concerns over public human health. Therefore, AMD was used as a model molecule in the FQICAs establishment and comparison based on the same bioreagents. The outstanding performance in technical parameters of the two FQICAs indicated that they could provide rapid, precise, reliable technical support for large-scale on-site screening for AMD detection. What's more, the systematic and comprehensive comparison of the two FQICAs would give useful suggestions for scientists and users in monitoring the harmful compounds.

Establishment of heparin-binding protein time-resolved immunoassay and some potential clinical applications.

AIM: To establish a highly sensitive time-resolved fluorescence immunoassay of heparin-binding protein (HBP-TRFIA) and evaluate its application value for bacterial or fungal infections in tumor patients. METHODS: Two types of HBP monoclonal specific antibodies against different epitopes of the antigen molecule were used as coating antibodies and Eu3+-labeled antibodies, respectively. The double-antibody sandwich method was used in establishing HBP-TRFIA, and the methodology was evaluated. The established HBP-TRFIA was used in detecting HBP concentration in the plasma samples of healthy individuals, patients with bacterial or fungal infections, and infected or uninfected patients with various types of tumors. RESULTS: The linear range of HBP-TRFIA was (0.11-530 ng/mL). Plasma HBP concentrations detected through HBP-TRFIA were consistent with the results of fluorescence quantitative immunochromatography (ρ = 0.964). The plasma HBP concentrations of infected tumor patients were significantly higher than those of uninfected tumor patients (P < 0.01). CONCLUSION: This study successfully established a highly sensitive HBP-TRFIA, which was highly comparable to commercially available fluorescent quantitative immunochromatographic kits and was able to facilitate the timely diagnosis of bacterial or fungal infections in patients with tumor.

Time-resolved immunoassay based on magnetic particles for the detection of diethyl phthalate in environmental water samples.

Diethyl phthalate (DEP) is an extensively used phthalic acid diester (PAEs) with estrogenic activity and the potential for carcinogenic and teratogenic effects. To monitor trace DEP in environmental waters, a sensitive direct competitive time-resolved fluoroimmunoassay based on magnetic particles (MPs) as solid support was established. For the assay system, the anti-DEP antibody was oriented on the surface of the MPs using goat anti-rabbit antibody as linkers, and DEP-OVA was labeled using Eu3+. Several physicochemical factors that potentially influence the assay performance of the proposed method were investigated in detail, including concentration of MPs, dilution of DEP-OVA-Eu3+ and incubation time. Under the optimized conditions, the method showed: (i) low limit of detection (LOD) of 5.92ng/L; (ii) satisfactory accuracy (recoveries, 91.97-134.54%) with good reproducibility (inter-CV, 4.17-9.17%; intra-CV, 7.41-14.72%). All of which indicated that the newly established method had much higher efficiency and great potential for use in environmental water analysis for DEP. In addition, the proposed immunoassay was applied for investigation of DEP in aquatic environments at Zhenjiang City. Our results showed that DEP was detected at the concentration of 2.98-65.18ng/mL in river samples and 46.95-306.19ng/mL in wastewater treatment plants (WWTPs), which showed rather high concentrations compared with reported data. Our study provides background data important for risk assessment and contamination control of DEP in the aquatic environment of this area.

Design and validation of a novel immunological test for enterolactone.

Enterolactone (ENL) is produced by the gut microflora from lignans found in edible plants. ENL is estrogenic with no effect on the E-screen test and is a natural Selected Estrogen Receptor Modulator (SERM) with health interests that have to be checked in clinical studies with bioavailability assessment. Two haptens of ENL were synthesized, with a spacer arm at the C5 position having either 2 or 4 carbon atoms (ENLΔ2 and ENLΔ4, respectively). Hapten coupling to bovine serum albumin (BSA) was characterized by MALDI mass spectrometry. Polyclonal antibodies were obtained against the BSA conjugates. Additional conjugates were generated by coupling to swine thyroglobulin (Thyr). Homologous and heterologous competitive ELISAs were developed with Thyr or BSA conjugates as coating. The best assays were validated on biological samples from mice. Both antibodies exhibited the same IC50 at 1.5 ng mL(-1) with a detection limit below 0.5 ng mL(-1). Most cross-reactions with structurally related lignans were lower than 0.03%. This new assay type is faster, more specific and more reliable than existing ones.