Ultrasensitive detection of E. coli O157:H7 with biofunctional magnetic bead concentration via nanoporous membrane based electrochemical immunosensor.
In this paper, biofunctional magnetic beads were investigated for bacterial cells concentration in a nanoporous alumina membrane based immunosensor for ultra-sensitive detection of E. coli O157:H7. The specific antibody modified magnetic beads were used for concentration of E coli O157:H7 from samples in a small region to enhance sensitivity. The magnetic bead conjugated E. coli O157:H7 cells were then captured on the nanoporous alumina membrane with immobilized antibody via assembled PEG-silane linker. Scanning electron microscopy and fluorescent microscopy were used to demonstrate the magnetic bead-bacteria cell conjugation and bacteria cells magnetic concentration, respectively. Impedance spectroscopy was used to monitor the pure E coli O157:H7 cells and magnetic bead conjugated E coli O157:H7 cells binding on antibody immobilized nanoporous membrane with or without magnetic field. Compared with direct detection of pure bacteria cells, this method via magnetic bead conjugation and concentration demonstrated the ultrasensitivity of 10 CFU/mL for E coli O157:H7 detection.
Interdisciplinary Division of Biomedical Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, PR China.
Ka Yiu
KY
Chan
Wei Wei
WW
Ye
Yu
Y
Zhang
Li Dan
LD
Xiao
Polly H M
PH
Leung
Yi
Y
Li
Mo
M
Yang
D000907:Antibodies, Bacterial / Q000737:chemistry / Q000276:immunology; D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D019453:Escherichia coli O157 / Q000276:immunology / Q000302:isolation & purification*; D007118:Immunoassay / Q000295:instrumentation*; D018189:Immunomagnetic Separation / Q000295:instrumentation*; D008567:Membranes, Artificial; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D016062:Porosity; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D000907:Antibodies, Bacterial; D008567:Membranes, Artificial