Functionalized biosensing surfaces were developed for chemiluminescent immunoassay of pesticides. Two approaches to construct functionalized surfaces were tested: (i) pesticide is immobilized to the surface and interacts with a labeled antibody; (ii) antibody is immobilized and interacts with a labeled pesticide. As labels alkaline phosphatase and peroxidase were used with their corresponding substrates CSPD and luminol, respectively. Light produced by chemiluminescent substrate was detected by a thermoelectrically cooled CCD camera or a photomultiplier. The best detection limit 0.00001 ng/ml was obtained using antibodies immobilized to dextran-enhanced surface. Completely renewable surface was obtained using reversible lectin-monosaccharide interaction, one surface was used for 200 analyses without any loss of binding capacity. Most favorable stability and cost per analysis was achieved with molecularly imprinted polymer (MIP) instead of antibody. The functionalized biosensing surfaces were prepared to detect 2,4-dichlorophenoxyacetic (2,4-D) acid as a model pesticide. The developed concepts are, however, generally applicable to other pesticides and to other optical formats, e.g. optical fiber.

Journal Article↗

PubMedDate not supplied

Biomaterials for molecular electronics development of optical biosensor for retinol.

Molecular electronics involves expertise from several branches of science. Various biomaterials and electronics are involved in the fabrication of such devices. While passive biomaterials are involved in anchoring the active biomolecules, the latter are involved in switching and/or signal transduction. In the present investigation we have used a glass-capillary-based approach to design a biosensor for retinol. The sensing element is retinol-binding protein (RBP). The affinity of retinoic-acid-horseradish peroxidase (conjugate) to RBP is tested using a surface plasmon resonance technique. A simple photomultiplier-tube-based system is exploited to monitor the chemiluminescent signal generated upon reaction of hydrogen peroxide and luminol with the conjugate bound to RBP. The photomultiplier tube is directly coupled to a computer for data logging.

Biocompatible Materials↗