Sensitive detection of Escherichia coli O157:H7 using Pt-Au bimetal nanoparticles with peroxidase-like amplification.
Escherichia coli O157:H7 is one of the most notorious foodborne pathogens causing serious disease at low infectious dose. To protect consumers from deadly foodborne E. coli O157:H7 infection, it is vital to develop a simple, reliable, sensitive and rapid method which can detect low level E. coli O157:H7 in foods at real-time. We have successfully developed a novel immunochromatographic assay (ICA) with enhanced sensitivity for the visual and quantitative detection of E. coli O157:H7. Sandwich-type immunoreactions were performed on the ICA, and Pt-Au bimetal nanoparticles (NPs) were accumulated on the test zone. The signal amplification is based on Pt-Au bimetal NPs possessing high peroxidase activity toward 3,3',5,5'-tetramethylbenzidine, which can produce characteristic colored bands and thus, enable visual detection of E. coli O157:H7 without instrumentation. The innovative aspect of this approach lies in the visualization and quantification of target pathogen through the detection of color intensity. Due to the excellent peroxidase activity of Pt-Au NPs, they emit strong visible color intensity in less than 1 min for visual observation even in low concentration range of E. coli O157:H7. Quantification was performed using a commercial assay meter. The sensitivity was improved more than 1000-folds compared to the conventional test strip based on colored gold-colloids. Although the feasibility was demonstrated using E. coli O157:H7 as a model analyte, this approach could be easily developed to be a universal signal amplification technique and applied to detection of a wide variety of foodborne pathogens and protein biomarkers.
School of Mechanical and Material Engineering, Washington State University, Pullman, WA 99164, United States; Key Laboratory of Animal Virology of Ministry of Agriculture, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu 730046, China.
Tao
T
Jiang
School of Mechanical and Material Engineering, Washington State University, Pullman, WA 99164, United States.
Yang
Y
Song
School of Mechanical and Material Engineering, Washington State University, Pullman, WA 99164, United States.
Tianxiang
T
Wei
School of Mechanical and Material Engineering, Washington State University, Pullman, WA 99164, United States.
He
H
Li
School of Mechanical and Material Engineering, Washington State University, Pullman, WA 99164, United States; Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164, United States.
Dan
D
Du
School of Food Science, Washington State University, Pullman, WA 99164, United States. Electronic address: meijun.zhu@wsu.edu.
Mei-Jun
MJ
Zhu
School of Mechanical and Material Engineering, Washington State University, Pullman, WA 99164, United States; Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164, United States. Electronic address: yuehe.lin@wsu.edu.
Yuehe
Y
Lin
D000497:Alloys / Q000737:chemistry; D058491:Bacterial Load / Q000295:instrumentation*; D040761:Biomimetic Materials / Q000737:chemistry; D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008839:Microelectrodes; D009195:Peroxidase / Q000737:chemistry; D010984:Platinum / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000497:Alloys; D010984:Platinum; D006046:Gold; D009195:Peroxidase
E. coli O157:H7; Immunochromatographic assay; Pathogens detection; Peroxidase; Pt–Au nanoparticles