Rapid, colorimetric and quantitative detection of microcystin-LR using glucose oxidase-modified magnetic beads, CRISPR/Cas12a and recombinase polymerase amplification strategies

Microcystin-LR (MC-LR) is a significant environmental pollutant that presents a substantial risk to public health. The monitoring with simple approaches is essential for the prevention and management of MC-LR. In this study, we present an aptasensor platform utilizing recombinase polymerase amplification (RPA)-CRISPR/Cas12a technology to accurately identify MC-LR. The MC-LR aptamers were attached to magnetic beads (MBs) following combination with cDNA by hybridization, resulting in the formation of the MB aptasensor. Subsequently, glucose oxidase (GOx)-modified MB were synthesized using single-stranded DNA (MB-ssDNA-GOx) in order to induce alterations in color upon exposure to the TMB-glucose system. The colorimetric signal was visible to the naked eye and exhibited a positive correlation with MC-LR concentration. The sensing platform described in this study demonstrated great sensitivity and achieved a limit of detection of 0.1 μg/L. Furthermore, this methodology exhibited exceptional selectivity and favorable recovery rates, hence showcasing its strong suitability for the analysis of actual water samples. Hence, the assay exhibites significant potential for future environmental monitoring.