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Updated: May 12, 2026
Optical Detection of E. coli Bacteria by Mesoporous Silicon Biosensors
Published on: November 20, 2013
Dual-mode biosensing system based on stimuli-responsive DNA hydrogel and polyadenine-AuNPs for sensitive and rapid
Huiyuan Wang1, Shiqi Yang1, Donglei Luan1
1International Research Center for Food and Health, Laboratory of Quality and Safety Risk Assessment for Aquatic Products on Storage and Preservation (Shanghai), Ministry of Agriculture, Shanghai Engineering Research Center of Aquatic-Product Process & Preservation, College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China.
Abstract:
Escherichia coli O157:H7 (E. coli O157:H7) poses public health risks due to its low infectious dose and high pathogenicity, highlighting the need for rapid, sensitive detection methods. We report a dual-mode colorimetric/fluorescent biosensor based on a stimuli-responsive DNA hydrogel and polyadenine (polyA)-gold nanoparticles (AuNPs) for detecting E. coli O157:H7. A polyacrylamide/DNA hybrid hydrogel with a FAM-labeled, polyA10-extended aptamer serves as the matrix. Target recognition induces aptamer release and hydrogel disassembly, triggering AuNP dispersion via polyA10 strands and fluorescence enhancement by aptamers. The sensor shows linear colorimetric and fluorescent responses over 1 × 103-1 × 109 CFU/mL, with detection limits of 97 CFU/mL (colorimetric) and 1 CFU/mL (fluorescent). In milk, mutton, and fish samples, recoveries of 95.6%-108.3% with relative standard deviations (RSDs) below 2.3% confirm high accuracy and reproducibility. This study introduces a dual-mode detection approach, combining "homologous activation and heterogeneous output," enabling rapid screening and quantitative analysis, offering a method for pathogen monitoring in food.
