کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10429597 909845 2005 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Prostate-specific antigen immunosensing based on mixed self-assembled monolayers, camel antibodies and colloidal gold enhanced sandwich assays
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Prostate-specific antigen immunosensing based on mixed self-assembled monolayers, camel antibodies and colloidal gold enhanced sandwich assays
چکیده انگلیسی
Prostate-specific antigen (PSA) is a valuable biomarker for prostate cancer screening. We developed a PSA immunoassay on a commercially available surface plasmon resonance biosensor. Our PSA receptor molecule consists of a single domain antigen-binding fragment, cAbPSA-N7, derived from dromedary heavy-chain antibodies and identified after phage display. It binds PSA with a high kon value of 1.9 × 106 M−1 s−1, and was covalently immobilised on a gold substrate via a mixed self-assembled monolayer (SAM) of alkanethiols by using carbodiimide-coupling chemistry in 10 mM acetate buffer pH 5.5 to obtain an optimal pre-concentration. The best performing and optimised mixed SAM consisted of (10%) 16-mercapto-1-hexadecanoic acid (16-MHA) for covalent cAbPSA-N7 immobilisation and (90%) 11-mercapto-1-undecanol (11-MUOH) to minimise non-specific adsorption of the analyte. In this way, two advantages are incorporated in a single coupling layer. Up to 28 fmol/mm2 of cAbPSA-N7 could be immobilised and 30% of its binding sites participate actively in PSA interaction. In addition, the optimised layer showed also optimal performance to assess physiological samples. Although PSA concentrations as low as 10 ng/ml could be detected directly, this detection limit could be enhanced to PSA levels in the sub ng/ml range by introducing a sandwich assay involving a biotinylated secondary antibody and streptavidin modified gold nanoparticles. This approach realises the PSA detection at clinical relevant concentrations.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biosensors and Bioelectronics - Volume 21, Issue 3, 15 September 2005, Pages 483-490
نویسندگان
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