Chemiluminescent immunoassay (CLIA) for urinary albumin

Chemiluminescence immunoassay for chloramphenicol

In recent years, various chemiluminescent clinical immunoassay kits have been widely applied to the detection of hormones. However, a kit for chloramphenicol (CAP) is often absent from most commercial product lists, even though it is important to control the levels of CAP residues in foodstuffs too. Therefore, we describe a simple, solid-phase chemiluminescence immunoassay (CLIA) for the measurement of CAP in foodstuffs. A rabbit anti-CAP IgG is passively adsorbed onto the walls of polypropylene plates. The labeled antigen is horseradish peroxidase (HRP) conjugate of CAP. Luminol solution is used as the substrate of HRP. The light yield is inversely proportional to the concentration of CAP. The method has a similar sensitivity (0.05 ng/ml), specificity, precision, and accuracy to a conventional enzyme immunoassay (EIA). The intra-assay and inter-assay CVs of ten samples were <8% and <20%, respectively, and the analytical recovery of the method was 87-100%. The experimental correlation coefficient of dilution was found to be 0.999 using milk supernatant as buffer. The detection limit for the method was 0.1-10 ng/ml, and it displayed good linearity.

Water-soluble conductive polymer homogeneous immunoassay (SOPHIA). A novel immunoassay capable of automation

Conductive polymers are extensively conjugated macromolecules able to conduct electricity in their doped state and having a UV-visible spectrum which undergoes important chromatic modifications when subjected to pH changes or to oxido-reductive processes. This article describes a novel homogeneous immunoassay in which a water-soluble conductive polymer is used as the label. When antigen-antibody binding occurs, the local pH near the complex is modified. Such a pH change is in turn able to induce modifications in the absorbance at a characteristic wavelength of a conductive polymer covalently linked to either the antigen or the antibody. Consequently, the extent of tracer binding can be directly monitored by photometry during incubation. We present examples which validate the concept and exemplify its applicability in quantitative competitive immunoassays for human C-reactive protein and human serum albumin, as performed in a Cobas-Mira automated analyzer.

Chemiluminescence and immunoassays

The principles of chemiluminescence and the application of chemiluminescent labels and substrates in immunoassays are reviewed. Various immunoassay formats and all known classes of chemiluminescent molecules, including 1,2-dioxetanes, luminol and derivatives, acridinium esters, oxalate esters and firefly luciferins are described as well as the many sensitizers and fluorescent enhancers. Recent promising developments are discussed.