Novel, rapid, and sensitive colorimetric detection of leucomalachite green using a specific aptamer

Leucomalachite green (LMG), a derivative antimicrobial agent, can accumulate in animal tissues for long periods and is categorized as a carcinogen affecting consumer health. Therefore, determining the contamination of aquatic products by LMG is necessary to prevent residual contamination. In the work described herein, the detection of LMG based on a colorimetric method using gold nanoparticles (AuNPs) was developed. The specificity of isolated single-stranded DNA aptamers to LMG was proven by using LMG and other antibiotics. The binding affinity of the LMG-aptamer showed a Kd value of 1.94 pM. Furthermore, a colorimetric detection module was successfully developed, showing a limit of detection (LOD) value of LMG at 250 nM using standard LMG substance. Taken together, this research demonstrates a rapid and sensitive method to detect chemical residues, reducing the possibility of contamination in fishery products. Considering these findings, the aptamer-based colorimetric approach might be feasible to utilize as a biosensing module, providing a rapid, inexpensive analysis method for detecting deposited chemical residues.