title: A new aptameric biosensor for cocaine based on surface-enhanced Raman scattering spectroscopy.
abstract: The present study reports the proof of principle of a reagentless aptameric sensor based on surface-enhanced Raman scattering (SERS) spectroscopy with "signal-on" architecture using a model target of cocaine. This new aptameric sensor is based on the conformational change of the surface-tethered aptamer on a binding target that draws a certain Raman reporter in close proximity to the SERS substrate, thereby increasing the Raman scattering signal due to the local enhancement effect of SERS. To improve the response performance, the sensor is fabricated from a cocaine-templated mixed self-assembly of a 3'-terminal tetramethylrhodamine (TMR)-labeled DNA aptamer on a silver colloid film by means of an alkanethiol moiety at the 5' end. This immobilization strategy optimizes the orientation of the aptamer on the surface and facilitates the folding on the binding target. Under optimized assay conditions, one can determine cocaine at a concentration of 1 muM, which compares favorably with analogous aptameric sensors based on electrochemical and fluorescence techniques. The sensor can be readily regenerated by being washed with a buffer. These results suggest that the SERS-based transducer might create a new dimension for future development of aptameric sensors for sensitive determination in biochemical and biomedical studies.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
authors.forename: Jiwei
authors.initials: J
authors.lastname: Chen
authors.forename: Jianhui
authors.initials: J
authors.lastname: Jiang
authors.forename: Xing
authors.initials: X
authors.lastname: Gao
authors.forename: Guokun
authors.initials: G
authors.lastname: Liu
authors.forename: Guoli
authors.initials: G
authors.lastname: Shen
authors.forename: Ruqin
authors.initials: R
authors.lastname: Yu
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques; D003042:Cocaine / Q000032:analysis*; D003102:Colloids / Q000737:chemistry; D008274:Magnesium / Q000737:chemistry; D009994:Osmolar Concentration; D010316:Particle Size; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry; D012964:Sodium / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties
chemical_list: D052157:Aptamers, Nucleotide; D003102:Colloids; D012834:Silver; D012964:Sodium; D008274:Magnesium; D003042:Cocaine