title: A novel electrochemical immunosensor based on colabeled silica nanoparticles for determination of total prostate specific antigen in human serum.
abstract: A novel electrochemical immunosensor using functionalized silica nanoparticles (Si NPs) as protein tracer has been developed for the detection of prostate specific antigen (PSA) in human serum. The immunosensor was carried out based on a heterogeneous sandwich procedure. The PSA capture antibody was immobilized on the gold electrode via glutaraldehyde crosslink. After reaction with the antigen in human serum, Si NPs colabeled with detection antibody and alkaline phosphatase (ALP) was sandwiched to form the immunocomplex on the gold electrode. ALP carried by Si NPs convert nonelectroactive substrate into the reducing agent and the latter, in turn, reduce metal ions to form electroactive metallic product on the electrode. Linear sweep voltammetry (LSV) was used to quantify the amount of the deposited silver and give the analytical signal for PSA. The parameters including the concentration of the ALP used to functionalize the Si NPs and the enzyme catalytic reaction time have been studied in detail and optimized. Under the optimum conditions of immunoreaction and electrochemical detection, the electrochemical immunosensor was able to realize a reliable determination of PSA in the range of 1-35 ng/mL with a detection limit of 0.76 ng/mL. For six human serum samples, the results performed with the electrochemical immunosensor were in good agreement with those obtained by chemiluminescent microparticle immunoassay (CMIA), indicating that the electrochemical immunosensor could satisfy the need of practical sample detection.
authors.affiliation: State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Bo
authors.initials: B
authors.lastname: Qu
authors.forename: Xia
authors.initials: X
authors.lastname: Chu
authors.forename: Guoli
authors.initials: G
authors.lastname: Shen
authors.forename: Ruqin
authors.initials: R
authors.lastname: Yu
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002623:Chemistry Techniques, Analytical / Q000379:methods; D004563:Electrochemistry / Q000379:methods*; D006801:Humans; D007118:Immunoassay; D008297:Male; D051379:Mice; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008863:Microspheres; D053758:Nanoparticles / Q000737:chemistry*; D017430:Prostate-Specific Antigen / Q000032:analysis* / Q000097:blood*; D012822:Silicon Dioxide / Q000737:chemistry*; D012834:Silver / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D012834:Silver; D012822:Silicon Dioxide; D017430:Prostate-Specific Antigen