title: Capillary waveguide fluoroimmunosensor with improved repeatability and detection sensitivity.
abstract: An optical capillary waveguide fluoroimmunosensor based on glass capillaries internally coated with an ultrathin poly(dimethylsiloxane) (PDMS) film is presented. The evaluation of the capillaries developed was done in comparison with aminosilanized [3-(aminopropyl)triethoxysilane, APTES] glass and poly(methylpentene) (PMP) capillaries by immobilizing rabbit gamma-globulins on the internal capillary wall. Following reaction with (R)-phycoerythrin-labelled antibody, the capillary was scanned with a laser beam and the fluorescence waveguided through the capillary wall was detected by a photomultiplier placed at one of its ends. The capillaries developed provided considerably improved protein coating homogeneity (intracapillary coefficients of variation 2.9-6.6%) and repeatability (intercapillary coefficients of variation 2.1-5.0%) compared with APTES-treated ones (7.9-13.4 and 8.5-15.2%, respectively). With use of these capillaries in a sandwich-type immunosensor for the determination of rabbit gamma-globulins, the assay detection limit was improved eightfold (4.4 ng/mL) compared with that obtained using PMP capillaries (35.3 ng/mL), whereas the assay repeatability was improved threefold (intra-assay coefficients of variation 5.9-13.1%) compared with APTES-treated capillaries (15.6-36%).
authors.affiliation: Immunoassay-Immunosensors Laboratory, Institute of Radioisotopes & Radiodiagnostic Products, N.C.S.R. Demokritos, Aghia Paraskevi, 15310, Athens, Greece.
authors.forename: Aristidis E
authors.initials: AE
authors.lastname: Niotis
authors.forename: Christos
authors.initials: C
authors.lastname: Mastichiadis
authors.forename: Panagiota S
authors.initials: PS
authors.lastname: Petrou
authors.forename: Ion
authors.initials: I
authors.lastname: Christofidis
authors.forename: Athanasia
authors.initials: A
authors.lastname: Siafaka-Kapadai
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Misiakos
authors.forename: Sotirios E
authors.initials: SE
authors.lastname: Kakabakos
mesh_terms: D000818:Animals; D000906:Antibodies / Q000737:chemistry; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D015200:Fluoroimmunoassay / Q000295:instrumentation / Q000379:methods*; D008567:Membranes, Artificial; D010799:Phycoerythrin / Q000737:chemistry; D011437:Propylamines; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012821:Silanes / Q000737:chemistry; D013499:Surface Properties; D005719:gamma-Globulins / Q000032:analysis
chemical_list: D000906:Antibodies; D004129:Dimethylpolysiloxanes; D008567:Membranes, Artificial; D011437:Propylamines; D012821:Silanes; D005719:gamma-Globulins; D010799:Phycoerythrin; C013830:baysilon; C477625:amino-propyl-triethoxysilane