Binding kinetics of human cellular prion detection by DNA aptamers immobilized on a conducting polypyrrole
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We developed a biosensor based on the surface plasmon resonance (SPR) method for the study of the binding kinetics and detection of human cellular prions (PrPC) using DNA aptamers as bioreceptors. The biosensor was formed by immobilization of various biotinylated DNA aptamers on a surface of conducting polypyrrole modified by streptavidin. We demonstrated that PrPC interaction with DNA aptamers could be followed by measuring the variation of the resonance angle. This was studied using DNA aptamers of various configurations, including conventional single-stranded aptamers that contained a rigid double-stranded supporting part and aptamer dimers containing two binding sites. The kinetic constants determined by the SPR method suggest strong interaction of PrPC with various DNA aptamers depending on their configuration. SPR aptasensors have a high selectivity to PrPC and were regenerable by a brief wash in 0.1 M NaOH. The best limit of detection (4 nM) has been achieved with this biosensor based on DNA aptamers with one binding site but containing a double-stranded supporting part.
KeywordsPrions Aptamers Kinetics SPR Polypyrrole
This work was supported by the Slovak Research and Development Agency (contracts No. APVV-0410-10, SK-FR-0025-09), by France Government, by Slovak Academy of Sciences under the project mnt-era.net (proposal No. 2009-50) and VEGA (project No. 1/0785/12). We are grateful to Dr. Human Rezaei and Dr. Jasmina Vidic from VIM group of INRA France for generous gift of PrPC proteins.
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