Target-induced gold nanoparticles colorimetric sensing coupled with aptamer for rapid and high-sensitivity detecting kanamycin.

Herein we report a novel colorimetric sensing strategy for the detection of kanamycin (kana) based on target-induced gold nanoparticles (AuNPs) coupled with aptamers. Aptamer-functionalized AuNPs, as the colorimetric probe, showed a distinct red shift with addition of kana, which avoiding the tedious and unnecessary additive-induced process. To study the interaction between kana and AuNPs and the effects of the specific aptamer adsorption, a series of experiments including UV-vis absorbance and surface enhanced Raman spectroscopy (SERS) were performed. Based on the results, a new alternative view is proposed that kana can directly induce the aggregation of aptamer-wrapped AuNPs, attributed to the co-adsorption of kana and aptamer on the surface of AuNPs. The proposed colorimetric sensing exhibited high selectivity and sensitivity for kanamycin assay with a wide linear range from 10.0 nM to 4.0 μM, and the limit of detection (LOD) reached 4.0 nM. Moreover, the whole detection process could be completed within 5 min, and it also achieved excellent performance in real samples detection with recoveries in the range of 86.22-109.89%. The results indicate that target-induced AuNPs colorimetric sensing coupled with aptamers for the direct detection of kana is simple, rapid and high-sensitivity, has the promising potential applications in the fields of food safety and environmental monitoring.