Immunomagnetic Separation Combined with RCA-CRISPR/Cas12a for the Detection of Salmonella typhimurium on a Figure-Actuated Microfluidic Biosensor.

Xinran Xiang, Gaowa Xing, Yuting Liu, Qianyu Wen, Yuhuan Wei, Jiaran Lu, Yuanyuan Chen, Yuhan Ji, Shuhan Chen, Tingting Liu, Yuting Shang

Journal of agricultural and food chemistry 2023 Sep 13

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A figure-actuated microfluidic biosensor was developed for the rapid and sensitive detection of Salmonella typhimurium using immunomagnetic separation to separate target bacteria and rolling circle amplification (RCA) combined with CRISPR/Cas12a to amplify the detection signal. The magnetic nanoparticles (MNPs) modified with the capture antibodies (MNPs@Ab1) and RCA primer linked with recognized antibodies (primer@Ab2) were first used to react with S. typhimurium, resulting in the formation of MNPs@Ab1-S. typhimurium-primer@Ab2 complexes. Then, the RCA and CRISPR/Cas12a reagents were successively pumped into the chamber and incubated at the appropriate conditions. With the help of a 3D-printed signal detector, the fluorescence signal was collected and analyzed using the smartphone APP for the determination of bacterial concentration. This biosensor exhibited a wide linear range for the detection of S. typhimurium with a low limit of detection of 1.93 × 102 CFU/mL and a mean recovery of about 106% in the spiked milk sample.

Citation

Xinran Xiang, Gaowa Xing, Yuting Liu, Qianyu Wen, Yuhuan Wei, Jiaran Lu, Yuanyuan Chen, Yuhan Ji, Shuhan Chen, Tingting Liu, Yuting Shang. Immunomagnetic Separation Combined with RCA-CRISPR/Cas12a for the Detection of Salmonella typhimurium on a Figure-Actuated Microfluidic Biosensor. Journal of agricultural and food chemistry. 2023 Sep 13;71(36):13518-13526