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Updated: May 3, 2026
Combination of Adhesive-tape-based Sampling and Fluorescence in situ Hybridization for Rapid Detection of Salmonella on Fresh Produce
Published on: October 18, 2010
A CRISPR/Cas12a-based direct transverse relaxation time biosensor via hydrogel sol-gel transition for Salmonella
Yafang Shen1, Bingyan Li2, Guijie Hao1
1Key Laboratory of Healthy Freshwater Aquaculture, Ministry of Agriculture and Rural Affairs; Huzhou Key Laboratory of Aquatic Product Quality Improvement and Processing Technology, Zhejiang Institute of Freshwater Fisheries, Huzhou 313001, China.
Abstract:
This research developed a magnetic relaxation switching (MRS) biosensor based on hydrogel sol-gel transition and the CRISPR/Cas12a system (MRS-CRISPR) to detect Salmonella. Herein, the alkaline phosphatase (ALP) labeled with streptavidin was captured by the biotin-modified DNA on magnetic nanoparticles (MNPs) surface, which generated an acidic environment via enzymatic reaction to release Ca2+ and induced the transformation of alginate sol to hydrogels. In contrast, Salmonella activated the trans-cleavage activity of the CRISPR/Cas12a system, interrupting the capture of ALP and the subsequent sol-gel transition. Then, transverse relaxation time (T2), which was regulated by the hydrogelation process was measured for Salmonella detection. The MRS-CRISPR biosensor enables sensitive detection of Salmonella with a detection limit of 158 CFU/mL. It directly alters the state of water molecules, overcoming the disadvantages of traditional MRS sensors that rely on MNPs to produce T2 signals indirectly. This method offers innovative insights for the application of the MRS technology in food safety analysis.
