Objective: To effectively and conveniently detect pathogenic bacteria, this study aimed to develop label-free biosensors fabricated affinity peptides that can recognize targeted bacteria strains and enable precise quantitative detections. Results: A 12-mer peptide with high binding affinity toward Escherichia coli O157:H7 was discovered by biopanning of phage-displayed peptide library. The peptide modified with glycine residues (G3) and one cysteine (C) residue at C-terminal, could self-assemble on gold electrodes, enabling electrochemical impedance spectroscopy (EIS) analysis for quantitative detection of E. coli O157:H7. This method showed a low detection limit of 20 CFU/mL and a liner range from 2 × 102 to 2 × 106 CFU/mL. Conclusion: It appears that, by designing and optimizing the structures of peptides, such a strategy can be greatly promising in developing quick, sensitive and quantitative biosensor of pathogens.
Bibliographical noteFunding Information:
This work was supported by the National Natural Science Foundation of China (Grant Nos.31471659, 21636003 and 21303050) and the Natural Science Foundation of Shanghai (Grant No.19ZR1412400).
© 2020, Springer Nature B.V.
- Affinity peptides
- E. coli O157:H7
- Electrochemical impedance spectroscopy