title: Alkaline phosphatase-catalyzed silver deposition for electrochemical detection.
abstract: Alkaline phosphatase (AP) is one of the most used enzymatic labels for the development of ELISAs, immunosensors, DNA hybridization assays, etc. This enzyme catalyzes the dephosphorylation of a substrate into a detectable product usually quantified by optical or electrochemical measurements. This work is based on a substrate (3-indoxyl phosphate) that produces a compound able to reduce silver ions in solution into a metallic deposit, which is localized where the enzymatic label AP is attached. The deposited silver is electrochemically stripped into solution and measured by anodic stripping voltammetry. Its application to an enzymatic genosensor on streptavidin-modified screen-printed carbon electrodes for the detection of virulence nucleic acid determinants of autolysin gene, exclusively present on the genome of the human pathogen Streptococcus pneumoniae, is described. Compared with the direct voltammetric detection of indigo carmine, the anodic stripping voltammetry of silver ions is 14-fold more sensitive.
authors.affiliation: Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo. 33006 Oviedo, Asturias, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Fanjul-Bolado
authors.forename: David
authors.initials: D
authors.lastname: Hernández-Santos
authors.forename: María Begoña
authors.initials: MB
authors.lastname: González-García
authors.forename: Agustín
authors.initials: A
authors.lastname: Costa-García
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D004269:DNA, Bacterial / Q000032:analysis*; D004566:Electrodes; D006801:Humans; D007211:Indoles / Q000378:metabolism*; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000235:genetics; D011199:Potentiometry / Q000379:methods*; D012834:Silver / Q000737:chemistry*; D019809:Streptavidin / Q000737:chemistry; D013296:Streptococcus pneumoniae / Q000235:genetics / Q000302:isolation & purification; D037521:Virulence Factors / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D007211:Indoles; D037521:Virulence Factors; C034083:indoxyl phosphate; D012834:Silver; D019809:Streptavidin; D000469:Alkaline Phosphatase; D009238:N-Acetylmuramoyl-L-alanine Amidase