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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. © 2001 Kluwer Academic Publishers

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.

Based on a molecularly imprinted polymer, a competitive binding assay analogous to competitive enzyme immunoassay has been developed. The assay is specific for the herbicide 2,4-dichlorophenoxyacetic acid and uses, for the first time, an enzyme-labelled conjugate as a tracer. The label tobacco peroxidase allowed for colorimetric and chemiluminescence detection. The molecularly imprinted polymer was synthesised in the form of microspheres by precipitation polymerisation. The polymer efficiently and selectively bound the analyte in aqueous solution. Calibration curves were obtained corresponding to analyte concentrations ranging from 40–600 μg mL⁻¹ for the colorimetric assay, and from 1–200 μg mL⁻¹ for chemiluminescence assay.

Molecular imprinting is a technology that allows for the creation of molecular recognition sites in synthetic polymers via the use of templates. Imprinted materials have been used in various applications, including stationary phases for chromatography, recognition elements in sensors, or antibody binding mimics in immunoassay-type analyses. In the present work, molecularly imprinted enantioselective polymer membranes are described. The amino acid derivative CBZ-tyrosine was chosen as the target compound. A CBZ-l-tyrosine-imprinted polymer was first tested in HPLC mode, and efficient resolution of racemic CBZ-tyrosine was obtained. Imprinted polymer membranes were prepared by casting the polymer in the pores of a polypropylene membrane, using a specifically adapted polymer recipe. In diffusion experiments across the imprinted membranes, enantioselectivity was observed with the diffusion of the l-enantiomer of CBZ-tyrosine (the original template) being faster than that of the d-enantiomer. Chirality 11:465–469, 1999. © 1999 Wiley-Liss, Inc.

Molecular imprinting is a technology that allows for the creation of molecular recognition sites in synthetic polymers via the use of templates. Imprinted materials have been used in various applications, including stationary phases for chromatography, recognition elements in sensors, or antibody binding mimics in immunoassay‐type analyses. In the present work, molecularly imprinted enantioselective polymer membranes are described. The amino acid derivative CBZ‐tyrosine was chosen as the target compound. A CBZ‐l‐tyrosine‐imprinted polymer was first tested in HPLC mode, and efficient resolution of racemic CBZ‐tyrosine was obtained. Imprinted polymer membranes were prepared by casting the polymer in the pores of a polypropylene membrane, using a specifically adapted polymer recipe. In diffusion experiments across the imprinted membranes, enantioselectivity was observed with the diffusion of the l‐enantiomer of CBZ‐tyrosine (the original template) being faster than that of the d‐enantiomer. Chirality 11:465–469, 1999. © 1999 Wiley‐Liss, Inc.

Abstract: Intracellular concentration of cAMP and phosphorylation of 15 kD protein in cultured mouse peritoneal macrophages are increased in the presence of arginine-vasopressin. Vasopressin, decreases adhesion of macrophages to plastic.