Polyacrylamide gel electrophoresis of semiconductor quantum dots and their bioconjugates: materials characterization and physical insights from spectrofluorimetric detection

A new method for the characterization of quantum dots and their conjugates reveals details that go unseen with other electrophoretic methods.

Analytical characterization of IgG–cTpp and IgG–Mn-cTpp conjugates

Herein, the conjugation of carboxylated tetraphenylporphyrin or its derivative containing manganese cation and model protein — immunoglobulin G is presented. The obtained IgG–cTpp and IgG–Mn-cTpp conjugates were subsequently used for model immunoassays construction. The IgG–cTpp formation was confirmed using size-exclusion chromatography. Thanks to the unique properties of applied labels the assay analysis was carried out with both spectrophotometric and spectrofluorimetric detection. The assays were performed creating semi-quantitative detection system using 96-well plates. The incubation time, ensuring full saturation of the surface with secondary antibodies was also optimized. Moreover, in the case of IgG–Mn-cTpp conjugates we present the possibility of both direct and indirect determination of the label, the latter based on the catalytic activity of Mn-cTpp, which allows for amplification of the measured signal. We proved that both cTpp and Mn-cTpp may be successfully used for protein labeling and serve as universal tracers for various formats of affinity assays and sensors.

Low density solvent based dispersive liquid–liquid microextraction followed by vortex-assisted magnetic nanoparticle based solid-phase extraction and surfactant enhanced spectrofluorimetric detection for the determination of aflatoxins in pistachio nuts

A novel extraction method based on DLLME followed by VA-D-SPE was developed to determine total aflatoxins in pistachio.