[Detection of Escherichia coli O157:H7 with piezoelectric immunosensor based on enhancement with immuno-nanoparticles]
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Updated: Jun 21, 2026
Foodborne Pathogen Screening Using Magneto-fluorescent Nanosensor: Rapid Detection of E. Coli O157:H7
Published on: September 17, 2017
Zhiqiang Shen1, Jingfeng Wang, Zhigang Qiu
1Institute of Hygiene and Environmental Medicine, Academy of Military Medical Sciences, Tianjin 300050, China. szq922990@126.com
Objective:
We developed a sensitive method to detect Escherichia coli O157:H7 based on enhancement with immuno-nanoparticles.
Method:
About 10 nm ultrafine immunomagnetic particles were prepared by a co-precipitation method, about 20 nm immuno-colloid-gold was prepared by sodium citrate reduction. The immunosensor was fabricated by using Protein A from Staphylococcus aureus (SPA) for the antibody immobilization. Two immuno-nanoparticles by two antibodies were used to amplify frequency changing.
Result:
The most suitable immobilization concentration and time for SPA was 1.2 mg/mL and 40 min, and dose for the antibody was 1.0 mg/mL and 60 min. With the signal amplification of the two immuno-nanoparticles, the detection limit of E. coli O157:H7 was increased from 10(4) colony-forming units (cfu)/mL to 10(1) cfu/mL.
Conclusion:
The prepared immuno-nanoparticles might be used to significantly amplify the frequency signal of the piezoelectric immunosensor and improve the detect sensitivity.
