title: Single walled carbon nanotube-based junction biosensor for detection of Escherichia coli.
abstract: Foodborne pathogen detection using biomolecules and nanomaterials may lead to platforms for rapid and simple electronic biosensing. Integration of single walled carbon nanotubes (SWCNTs) and immobilized antibodies into a disposable bio-nano combinatorial junction sensor was fabricated for detection of Escherichia coli K-12. Gold tungsten wires (50 µm diameter) coated with polyethylenimine (PEI) and SWCNTs were aligned to form a crossbar junction, which was functionalized with streptavidin and biotinylated antibodies to allow for enhanced specificity towards targeted microbes. In this study, changes in electrical current (ΔI) after bioaffinity reactions between bacterial cells (E. coli K-12) and antibodies on the SWCNT surface were monitored to evaluate the sensor's performance. The averaged ΔI increased from 33.13 nA to 290.9 nA with the presence of SWCNTs in a 10(8) CFU/mL concentration of E. coli, thus showing an improvement in sensing magnitude. Electrical current measurements demonstrated a linear relationship (R2 = 0.973) between the changes in current and concentrations of bacterial suspension in range of 10(2)-10(5) CFU/mL. Current decreased as cell concentrations increased, due to increased bacterial resistance on the bio-nano modified surface. The detection limit of the developed sensor was 10(2) CFU/mL with a detection time of less than 5 min with nanotubes. Therefore, the fabricated disposable junction biosensor with a functionalized SWCNT platform shows potential for high-performance biosensing and application as a detection device for foodborne pathogens.
authors.affiliation: Department of Human Nutrition, Food, and Animal Sciences, University of Hawaii, Honolulu, Hawaii, United States of America.
authors.forename: Kara
authors.initials: K
authors.lastname: Yamada
authors.affiliation: Korea Food Research Institute, Seongnam-si, Republic of Korea.
authors.forename: Chong-Tai
authors.initials: CT
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, University of Washington, Seattle, Washington, United States of America.
authors.forename: Jong-Hoon
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, University of Washington, Seattle, Washington, United States of America.
authors.forename: Jae-Hyun
authors.initials: JH
authors.lastname: Chung
authors.affiliation: Department of Food and Nutrition, Hanyang University, Seoul, Republic of Korea.
authors.forename: Hyeon Gyu
authors.initials: HG
authors.lastname: Lee
authors.affiliation: Department of Human Nutrition, Food, and Animal Sciences, University of Hawaii, Honolulu, Hawaii, United States of America.
authors.forename: Soojin
authors.initials: S
authors.lastname: Jun
mesh_terms: D000907:Antibodies, Bacterial / Q000276:immunology; D055910:Antibodies, Immobilized / Q000276:immunology; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D004553:Electric Conductivity; D004927:Escherichia coli Infections / Q000175:diagnosis*; D048168:Escherichia coli K12 / Q000276:immunology*; D059022:Food Safety; D005517:Foodborne Diseases / Q000175:diagnosis* / Q000382:microbiology; D006046:Gold; D064088:Hazard Analysis and Critical Control Points / Q000379:methods; D037742:Nanotubes, Carbon / Q000382:microbiology*; D012680:Sensitivity and Specificity; D014414:Tungsten
chemical_list: D000907:Antibodies, Bacterial; D055910:Antibodies, Immobilized; D037742:Nanotubes, Carbon; D006046:Gold; D014414:Tungsten