Simultaneous detection of two pesticides by colorimetric and fluorescence dual-response sensor based on aptamer and gold nanoparticles

We have designed a sensor based on gold nanoparticles (AuNPs) and aptamers for two pesticides detection. Two complementary paired aptamers have been carefully designed to adsorb onto the surface of AuNPs, serving as binding elements and molecular switches for pesticides. Aptamers not only give AuNPs the ability of colorimetric detection, but also has the ability of fluorescence detection, and AuNPs can improve the stability of aptamers. Thiamethoxam (TMX) and Acetamiprid (ACE) and their corresponding aptamers (Tapt and Aapt) were selected as models. When TMX is added, Tapt can bind to it and trigger the aggregation of AuNPs which can be used as the detection signal of colorimetric detection. When ACE is added, Aapt can bind to it and produce fluorescence. ACE does not cause colorimetric reaction, and TMX does not cause fluorescence. By using both colorimetric and fluorescent detection methods, interference free detection of two targets can be achieved.