Highly selective and sensitive visual detection of oxytetracycline based on aptamer binding-mediated the anti-aggregation of positively charged gold nanoparticles

This paper developed a colorimetric method for the determination of oxytetracycline by using cysteamine-stabilized gold nanoparticles (cysteamine-AuNPs) as the color indicator and oxytetracycline-binding aptamers (OBA) as the recognition element. It was proposed by means of the anti-aggregation of cysteamine-stabilized AuNPs induced by the specific recognition of OBA with oxytetracycline. The method was applied in milk samples with satisfactory recoveries, which are in full consistence with the results from HPLC. It widens the application prospect for the determination of small molecules with long-sequence aptamers.