Abstract
A single-stranded DNA (ssDNA) aptamer was successfully developed to specifically bind to nicotinamide phosphoribosyl transferase (Nampt) through systematic evolution of ligands by exponential enrichment (SELEX) and successfully implemented in a gold-interdigitated (GID) capacitor-based biosensor. Surface plasmon resonance (SPR) analysis of the aptamer revealed high specificity and affinity (Kd=72.52nM). Changes in surface capacitance/charge distribution or dielectric properties in the response of the GID capacitor surface covalently coupled to the aptamers in response to changes in applied AC frequency were measured as a sensing signal based on a specific interaction between the aptamers and Nampt. The limit of detection for Nampt was 1ng/ml with a dynamic serum detection range of up to 50ng/ml; this range includes the clinical requirement for both normal Nampt level, which is 15.8ng/ml, and Nampt level in type 2 diabetes mellitus (T2DM) patients, which is 31.9ng/ml. Additionally, the binding kinetics of aptamer-Nampt interactions on the capacitor surface showed that strong binding occurred with increasing frequency (range, 700MHz-1GHz) and that the dissociation constant of the aptamer under the applied frequency was improved 120-240 times (Kd=0.3-0.6nM) independent on frequency. This assay system is an alternative approach for clinical detection of Nampt with improved specificity and affinity.
Original language | English |
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Pages (from-to) | 233-238 |
Number of pages | 6 |
Journal | Biosensors and Bioelectronics |
Volume | 38 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2012 Oct |
Keywords
- Aptamer
- Capacitive biosensor
- Nampt (PBEF/visfatin)
- SELEX
ASJC Scopus subject areas
- Biotechnology
- Biophysics
- Biomedical Engineering
- Electrochemistry