CRISPR-Cas12a cleavage-based fluorescence biosensor to detect arsenic content in rice grains from different regions of China.

Nano-based sensors play a significant role in detection of heavy metals. Arsenic contaminated rice poses a serious health hazard. Nano-based rapid detection of arsenic (As3+) in rice is essential to perform rapid detection. To resolve the above problem, we leveraged the trans-cleavage activity of CRISPR -Cas12a in combination with an "aptamer-locker" DNA sensor design to develop a biosensor. The sensor exhibited a linear detection range of 0 to 7.5 ng/L and minimum detectable concentrations of 0.41 nM for As3+. The sensor developed for As3+ detection in rice exhibited strong specificity, high sensitivity and rapid analysis speed, in a few simple steps. Using this biosensor, we detected As3+ content in rice samples collected from local markets across China. All the tested 81 rice samples were below tolerable limits, the As3+ level ranged from 3.7 ± 0.1 μgkg-1 from Sichuan to 141.7 ± 5.3 μgkg-1 from Henan province in China.