Detection of Pesticide Residues Based on a Porous Silicon Optical Biosensor With a Quantum Dot Fluorescence Label

Abstract

In this paper, a grayscale variation of fluorescence Image based on porous silicon (PSi) Bragg mirrors (Bm) was proposed to detect pesticides quickly and easily. In this way, CdSe/ZnS quantum dots (QDs) were used as fluorescence labelling to weaken the fluorescence intensity, and a digital imaging method was used for detection. The QDs were coupled with complementary strand aptamers and interacted with aptamers immobilized on the PSi‘inner wall; thus, the fluorescence of the QDs produced by the PSi Bm was further enhanced. Acetamiprid would bind specifically to its corresponding aptamer, the complementary strand aptamers of the coupled QD would be replaced, and the fluorescence intensity would weaken. The fluorescence image of the PSi Bm surface was acquired by imaging device, and the acetamiprid pesticide was detected by computing the average grey value variation of the image. Experimental results presented that the variation in the average grey value increased with increasing pesticide concentration and presented a linear relationship within a certain range. The detection limit of acetamiprid pesticide with this type of way was 2.8 nM, indicating that this method achieved a low-cost, rapid and simple detection of pesticide.