Microbead QD-ELISA: Microbead ELISA Using Biocatalytic Formation of Quantum Dots for Ultra High Sensitive Optical and Electrochemical Detection.
ACS Appl Mater Interfaces
; 8(43): 29252-29260, 2016 Nov 02.
Article
en En
| MEDLINE
| ID: mdl-27753498
ABSTRACT
Electrochemical detection strategies employing semiconductor quantum dots (QDs) open up new opportunities for highly sensitive detection of biological targets. We designed a new assay based on microbead linked enzymatic generation of CdS QDs (Microbead QD-ELISA) and employed it in optical and electrochemical affinity assays for the cancer biomarker superoxide dismutase 2 (SOD2). Biotinylated antibodies against SOD2 were immobilized on the surface of polyvinyl chloride microbeads bearing streptavidin. In order to prevent any non-specific adsorption the microbeads were further blocked with bovine serum albumin. The analyte, SOD2 was captured on microbeads and labeled with alkaline phosphatase-conjugated antibody linked with mouse antibody against SOD2. Hydrolysis of para-nitrophenylphosphate by immobilized alkaline phosphatase triggered the rapid formation of phosphate-stabilized CdS QDs on the surface of microbeads. The resulting semiconductor nanoparticles were detected by fluorescence spectroscopy, microscopy, and square-wave voltammetry (SWV). The electrochemical assay based on the detection with square-wave voltammograms of Cd2+ ions originating from immobilized CdS QDs showed linearity up to 45 ng mL-1, and the limit of SOD2 detection equal to 0.44 ng mL-1 (1.96 × 10-11 M). This detection limit is lower by 2 orders of magnitude in comparison with that of other previously published assays for superoxide dismutase. The electrochemical assay was validated with HepG2 (Human hepatocellular carcinoma) cell lysate containing SOD2.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Puntos Cuánticos
Tipo de estudio:
Diagnostic_studies
Límite:
Animals
/
Humans
Idioma:
En
Revista:
ACS Appl Mater Interfaces
Asunto de la revista:
BIOTECNOLOGIA
/
ENGENHARIA BIOMEDICA
Año:
2016
Tipo del documento:
Article
País de afiliación:
España