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
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
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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 1.9Â ÃÂ 106Â Mâ1Â sâ1, and was covalently immobilised on a gold substrate via a mixed self-assembled monolayer (SAM) of alkanethiols by using carbodiimide-coupling chemistry in 10Â 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 28Â 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 10Â 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
Journal: Biosensors and Bioelectronics - Volume 21, Issue 3, 15 September 2005, Pages 483-490
نویسندگان
Lieven Huang, Gunter Reekmans, Dirk Saerens, Jean-Michel Friedt, Filip Frederix, Laurent Francis, Serge Muyldermans, Andrew Campitelli, Chris Van Hoof,