title: Label-free detection of pathogenic bacteria via immobilized antimicrobial peptides.
abstract: A novel label-free strategy for the detection of bacteria was developed by using a specific antimicrobial peptide (AMP)-functionalized quartz crystal microbalance (QCM) electrode. This electrode interface was successfully applied to detect pathogenic Escherichia coli O157:H7 based on the specific affinity between the small synthetic antimicrobial peptide and the bacterial cell of pathogenic E. coli O157:H7. The concentrations of pathogenic E. coli O157:H7 were sensitively measured by the frequency response of the QCM with a detection limit of 0.4 cfu μL(-1). The detection can be fulfilled within 10 min because it does not require germiculture process. On the other hand, if the specific antimicrobial peptides were immobilized on a gold electrode, this label-free strategy can also be performed by electrochemical impedance spectroscopy (EIS). Compared with QCM technique, the EIS measurement gives a lower sensitivity and needs a longer assay time. The combination of antimicrobial peptides with the real-time responses of QCM, as well as electronic read-out monitoring of EIS, may open a new way for the direct detection of bacteria.
authors.affiliation: College of Environmental Science and Engineering, Anhui Normal University, Wuhu 241000, PR China.
authors.forename: Zong-Mu
authors.initials: ZM
authors.lastname: Dong
authors.affiliation: College of Environmental Science and Engineering, Anhui Normal University, Wuhu 241000, PR China. Electronic address: gczhao@mail.ahnu.edu.cn.
authors.forename: Guang-Chao
authors.initials: GC
authors.lastname: Zhao
mesh_terms: D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry* / Q000378:metabolism*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D058266:Dielectric Spectroscopy; D004566:Electrodes; D019453:Escherichia coli O157 / Q000166:cytology / Q000302:isolation & purification*; D006046:Gold / Q000737:chemistry; D055767:Immobilized Proteins / Q000737:chemistry / Q000378:metabolism; D057230:Limit of Detection; D008969:Molecular Sequence Data; D058525:Quartz Crystal Microbalance Techniques; D013499:Surface Properties; D014871:Water Microbiology
chemical_list: D023181:Antimicrobial Cationic Peptides; D055767:Immobilized Proteins; D006046:Gold
keywords: Antimicrobial peptide; Biorecognition; Pathogenic Escherichia coli O157:H7; Quartz crystal microbalance