Highly sensitive electrochemical detection of proteins using aptamer-coated gold nanoparticles and surface enzyme reactions
| Autor: | Eun Ji Nam, Hyungi Kim, Hye Jin Lee, Eum Ji Kim, Alastair W. Wark, Sangchul Rho |
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| Rok vydání: | 2012 |
| Předmět: |
Surface Properties
Aptamer Metal Nanoparticles Nanoparticle Nanotechnology Biosensing Techniques Conjugated system Biochemistry Analytical Chemistry Monolayer Electrochemistry medicine Animals Humans Environmental Chemistry Spectroscopy medicine.diagnostic_test Chemistry Substrate (chemistry) Aptamers Nucleotide Immunoglobulin E Alkaline Phosphatase Combinatorial chemistry Colloidal gold Immunoassay Electrode Cats Gold |
| Zdroj: | The Analyst. 137:2011 |
| ISSN: | 1364-5528 0003-2654 |
| DOI: | 10.1039/c2an15994e |
| Popis: | A novel electrochemical detection methodology is described for the femtomolar detection of proteins which utilizes both DNA aptamer-functionalized nanoparticles and a surface enzymatic reaction. Immunoglobulin E (IgE) was used as a model protein biomarker, which possesses two distinct epitopes for antibody (anti-IgE) and DNA aptamer binding. A surface sandwich assay format was utilized involving the specific adsorption of IgE onto a gold electrode surface that was pre-modified with a monolayer of aptamer-nanoparticle conjugates followed by the specific interaction of alkaline phosphatase (ALP) conjugated anti-IgE. To clearly demonstrate the signal enhancement associated with nanoparticle use, anodic current measurements of the ALP catalyzed oxidation of the enzyme substrate 4-aminophenylphosphate (APP) were also compared with electrode surfaces upon which the aptamer was directly attached. The detection of an unlabelled protein at concentrations as low as 5 fM is a significant improvement compared to conventional electrochemical-based immunoassay approaches and provides a foundation for the practical use and incorporation of nanoparticle-enhanced detection into electrochemical biosensing technologies. |
| Databáze: | OpenAIRE |
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