title: Hollow mesoporous silica microspheres as sensitive labels for immunoassay of prostate-specific antigen.
abstract: A novel electrochemical immunosensor for sensitive detection of cancer biomarker prostate-specific antigen (PSA) has been reported based on nanoporous gold (NPG) and hollow mesoporous silica microspheres (HSMs). The immunoassay was conducted by following the typical procedure for sandwich-type immunoreaction. Nanoporous gold (NPG) foils were immobilized onto a glassy carbon electrode (GCE) for primary anti-PSA (Ab(1)) anchoring. Making use of the unique properties of NPG, antibodies could be self-assembled onto the support-free NPG via amine-Au affinity with a high loading amount and reserve high immunological activity. HSMs were used as a secondary anti-PSA antibody (Ab(2)) label. For the preparation of the label, mediator thionine (TH) was first conjugated onto amino-functionalized HSMs (NH(2)-HSMs) via crosslinking with glutaraldehyde, and then the amino group of TH was used to immobilize horseradish peroxidase (HRP) and Ab(2). Due to the large specific surface area of NH(2)-HSMs, the loading of antibodies as well as mediator and enzyme onto HSMs was substantially increased, which increased the sensitivity of the immunosensor. The immunosensor exhibited a high sensitivity and showed a linear response within the range of 0.01-10 ng mL(-1) PSA, low detection limit (6.00 pg mL(-1)), good reproducibility and stability. Significantly, the new method may be quite promising, with potential broad applications for clinical immunoassays.
authors.affiliation: Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan, 250022, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Wu
authors.forename: Ru
authors.initials: R
authors.lastname: Li
authors.forename: Haixia
authors.initials: H
authors.lastname: Wang
authors.forename: Shiquan
authors.initials: S
authors.lastname: Liu
authors.forename: Huan
authors.initials: H
authors.lastname: Wang
authors.forename: Qin
authors.initials: Q
authors.lastname: Wei
authors.forename: Bin
authors.initials: B
authors.lastname: Du
mesh_terms: D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D008297:Male; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D017430:Prostate-Specific Antigen / Q000032:analysis*; D015203:Reproducibility of Results; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D012822:Silicon Dioxide; D017430:Prostate-Specific Antigen