1. Impedance based detection of pathogenic E. coli O157:H7 using a ferrocene-antimicrobial peptide modified biosensor
- Author
-
Nan Wang, Yongxin Li, Farkhondeh Fathi, Heinz-Bernhard Kraatz, Rouzbeh Afrasiabi, Zhe She, Cuili Xiang, and Ryan Love
- Subjects
Conductometry ,Metallocenes ,Biomedical Engineering ,Biophysics ,Analytical chemistry ,Peptide ,Bacillus subtilis ,Biosensing Techniques ,medicine.disease_cause ,Escherichia coli O157 ,chemistry.chemical_compound ,Staphylococcus epidermidis ,Electrochemistry ,medicine ,Ferrous Compounds ,Escherichia coli ,chemistry.chemical_classification ,Chromatography ,biology ,Magainin ,Pathogenic bacteria ,General Medicine ,Equipment Design ,biology.organism_classification ,Bacterial Load ,3. Good health ,Dielectric spectroscopy ,Equipment Failure Analysis ,chemistry ,Gold ,Biosensor ,Microelectrodes ,Biotechnology ,Antimicrobial Cationic Peptides - Abstract
Escherichia coli O157:H7 can cause life-threatening gastrointestinal diseases and has been a severe public health problem worldwide in recent years. A novel biosensor for the detection of E. coli O157:H7 is described here using a film composed of ferrocene-peptide conjugates, in which the antimicrobial peptide magainin I has been incorporated as the biorecognition element. Electrochemical impedance spectroscopy was employed to investigate the surface characteristics of the newly developed biosensor and to monitor the interactions between the peptide film and the pathogenic bacteria. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were employed to confirm the immobilization of ferrocene-conjugate onto the gold surface. Non-pathogenic E. coli K12, Staphylococcus epidermidis and Bacillus subtilis were used in this study to evaluate the selectivity of the proposed biosensor. The results have shown the order of the preferential selectivity of the method is E. coli O157:H7>non-pathogenic E. coli>gram positive species. The detection of E. coli O157:H7 with a sensitivity of 10(3)cfu/mL is enabled by the biosensor. The experimental conditions have been optimized and the plot of changes of charge transfer resistance (ΔRCT) and the logarithm of the cell concentration of E. coli O157:H7 shows a linear correlation in the range of 10(3)-10(7)cfu/mL with a correlation coefficient of 0.983.
- Published
- 2013