title: Photoelectrochemical detection of enzymatically generated CdS nanoparticles: Application to development of immunoassay.
abstract: We report an innovative photoelectrochemical process (PEC) based on graphite electrode modified with electroactive polyvinylpyridine bearing osmium complex (Os-PVP). The system relies on the in situ enzymatic generation of CdS quantum dots (QDs). Alkaline phosphatase (ALP) catalyzes the hydrolisis of sodium thiophosphate (TP) to hydrogen sulfide (H2S) which in the presence Cd(2+) ions yields CdS semiconductor nanoparticles (SNPs). Irradiation of SNPs with the standard laboratory UV-illuminator (wavelength of 365 nm) results in photooxidation of 1-thioglycerol (TG) mediated by Os-PVP complex on the surface of graphite electrode at applied potential of 0.31 V vs. Ag/AgCl. A novel immunoassay based on specific enzyme linked immunosorbent assay (ELISA) combined with the PEC methodology was developed. Having selected the affinity interaction between bovine serum albumine (BSA) with anti-BSA antibody (AB) as a model system, we built the PEC immunoassay for AB. The new assay displays a linear range up to 20 ngmL(-1) and a detection limit (DL) of 2 ngmL(-1) (S/N=3) which is lower 5 times that of the traditional chromogenic ELISA test employing p-nitro-phenyl phosphate (pNPP).
authors.affiliation: Biofunctional Nanomaterials Unit, CIC BiomaGUNE, Parque Tecnológico de San Sebastián, Paseo Miramón 182, Donostia-San Sebastián 20009, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Barroso
authors.affiliation: Biofunctional Nanomaterials Unit, CIC BiomaGUNE, Parque Tecnológico de San Sebastián, Paseo Miramón 182, Donostia-San Sebastián 20009, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Saa
authors.affiliation: Biofunctional Nanomaterials Unit, CIC BiomaGUNE, Parque Tecnológico de San Sebastián, Paseo Miramón 182, Donostia-San Sebastián 20009, Spain.
authors.forename: Ruta
authors.initials: R
authors.lastname: Grinyte
authors.affiliation: Biofunctional Nanomaterials Unit, CIC BiomaGUNE, Parque Tecnológico de San Sebastián, Paseo Miramón 182, Donostia-San Sebastián 20009, Spain. Electronic address: vpavlov@cicbiomagune.es.
authors.forename: Valeri
authors.initials: V
authors.lastname: Pavlov
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation; D019187:Cadmium Compounds / Q000032:analysis*; D003217:Conductometry / Q000295:instrumentation*; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry; D007118:Immunoassay / Q000295:instrumentation*; D053768:Metal Nanoparticles / Q000032:analysis* / Q000737:chemistry* / Q000648:ultrastructure; D010783:Photometry / Q000295:instrumentation; D018036:Selenium Compounds / Q000032:analysis*
chemical_list: D019187:Cadmium Compounds; D004800:Enzymes, Immobilized; D018036:Selenium Compounds; D006108:Graphite; C058667:cadmium selenide; D000469:Alkaline Phosphatase
keywords: Alkaline phosphatase; ELISA; Enzyme catalysis; Immunoassay; Photoelectrochemistry; Quantum dots