Detection of pyrethroids by spectral correlation interferometry

Abstract

A label free method based on spectral correlation interferometry has been developed for highly sensitive detection of pyrethroids by competitive immunoassay on the surface of sensor chips made of widely available microscopy glass cover slips. It is shown that the method allows independent optimization of each step of the sensor surface modification. This fact may be used to increase the efficiency of development of protocols for a wide spectrum of immunoassays that employ glass surface as a solid phase. Detection of 3 phenoxybenzoic acid, which is one of the most stable metabolites of a large number of pyrethroids, on the surface of the optimized sensor chips has been demonstrated on the level of 15 pg/ml. That is 50 times better than the sensitivity of the enzyme linked immunosorbent assay (ELISA).

Direct immunosensing by spectral correlation interferometry: assay characteristics versus antibody immobilization chemistry

“…It is known that assay characteristics are strongly affected by immobilized bioreceptor molecules and by their orientation [34], sometimes resulting in more than 10-fold improvement in LOD [35]. In the present study, we further extend the protocols initially tested in [35] for the well-reproducible fabrication of epoxylated, biotinylated, and carboxylated sensor chips according to the scheme shown in Fig.…”

“…In the present study, we further extend the protocols initially tested in [35] for the well-reproducible fabrication of epoxylated, biotinylated, and carboxylated sensor chips according to the scheme shown in Fig. 2.…”

Development of Immunoassays Using Interferometric Real-Time Registration of Their Kinetics

“…The chemical modifications of the glass surface described below were performed according to the techniques developed for the detection of the cardiac troponin concentration based on the approaches discussed in [32]. …”

“…Determination of the observed kinetic association constant was based on the theoretical model of equilibrium association [32] adapted to the biosensor system in use. The values of the kinetic constants of association k a and dissociation k d as well as of the maximal signal R max were chosen to provide best fitting of the observed sensogram sections during passing the analyte at concentration C to the approximating function: …”

“…These methods were successfully employed for quantitative detection of conformational changes in polymers [30], identification of disease markers in blood serum [31], pyrethroids in environmental monitoring [32], and discovering the functional mechanisms of drugs [33]. …”