Publication Type:Journal Article
Source:Langmuir : the ACS journal of surfaces and colloids, Volume 27, Number 23, p.14696-702 (2011)
ISBN:1520-5827 (Electronic)<br/>0743-7463 (Linking)
Keywords:Aptamers, Nucleotide/*chemistry, Biosensing Techniques/instrumentation/*methods, Cocaine/*analysis, Surface Properties
<p>A cocaine-specific aptamer was used as a receptor molecule in a microcantilever-based surface stress sensor for detection of cocaine molecules. An interferometric technique that relies on measuring differential displacement between two microcantilevers (a sensing/reference pair) was utilized to measure the cocaine/aptamer binding induced surface stress changes. Sensing experiments were performed for different concentrations of cocaine from 25 to 500 muM in order to determine the sensor response as a function of cocaine concentration. In the lower concentration range from 25 to 100 muM, surface stress values increased proportionally to coverage of aptamer/cocaine complexes from 11 to 26 mN/m. However, as the cocaine concentration was increased beyond 100 muM, the surface stress values demonstrated a weaker dependence on the affinity complex surface coverage. On the basis of a sensitivity of 3 mN/m for the surface stress measurement, the lowest detectable threshold for the cocaine concentration is estimated to be 5 muM. Sensing cantilevers could be regenerated and reused because of reversible thermal denaturation of aptamer.</p>
Kang, Kyungho<br/>Sachan, Ashish<br/>Nilsen-Hamilton, Marit<br/>Shrotriya, Pranav<br/>Langmuir. 2011 Dec 6;27(23):14696-702. doi: 10.1021/la202067y. Epub 2011 Sep 14.