A facile and sensitive SERS-based biosensor for colormetric detection of acetamiprid in green tea based on unmodified gold nanoparticles

摘要

Surface-enhanced Raman scattering (SERS) has gained a reputation as one of the most sensitive spectroscopic methods for biosensing. However, to design a SERS-based biosensor, almost all currently used methods involve the time-consuming and complicated modification of the metallic nanoparticles, which restricts their wide spread applications. Herein, a facile and sensitive SERS-based aptasensor for colorimetric detection of acetamiprid (AC) was demonstrated. The prepared crystal violet (CV)-aptamer decorated gold nanoparticles (GNPs) tended to aggregate in a solution with high concentrations of salt, and displayed a purple color. In the presence of AC, the specific binding of the target with the aptamer generated conformation changes of aptamer (confirmed by the circular dichroism spectrum), which made the stable GNPs aggregation in the salt solution, thus resulting the SERS signal enhanced. Sequel, the SERS intensity was increased linearly with the concentration of AC ranging from 3.0x10(-8) to 4.0x10(-6)M, with a relatively low limit of 1.76x10(-8)M. The detection ability of AC by this biosensor was also confirmed with different adulterated tea. This approach is not only straightforward in fabrication but also cost-effective in operation, and can be used for diverse bio-molecules detection by changing the aptamer.