title: Piezoresistive microcantilever-based DNA sensor for sensitive detection of pathogenic Vibrio cholerae O1 in food sample.
abstract: Pathogenic Vibrio cholerae produces a cholera toxin which is the cause of a severe diarrheal disease called "Cholera". Available detection methods, including standard bacteriological test and immuno-based detection, are specific to the suspected pathogenic V. cholerae O1 and O139, but they are not specific to the cholera toxin producible strain. This work combined the polymerase chain reaction (PCR) of cholera toxin gene, ctxA gene, and microcantilever-based DNA sensor to improve the sensitivity and specificity of detection. Gold coated microcantilever, 250 µm long and 50 µm wide, with an embedded polysilicon wire acting as a piezoresistive material was modified by a self-assembled monolayer (SAM) of 3-mercaptopropionic acid (MPA) for immobilization of specific DNA probe via avidin layer on the surface. The avidin and 5' biotinylated single-stranded DNA (ssDNA) probe concentrations were optimized for the immobilization at 50 µg/mL and 1 µM, respectively. The hybridization between ssDNA probe on this DNA sensor and target DNA creates nanomechanical bending and resistance change of piezoresistive material inside the beam. This microcantilever-based DNA sensor offers a detection sensitivity of 3.25 pg or 14 nM of DNA template for ctxA gene detection. The lowest number of V. cholerae O1 in food sample with and without the enrichment process that the polymerase chain reaction (PCR) for ctxA gene combined with this DNA sensor can detect is 0.835 and 835 cells/g, respectively. This detection sensitivity is 10 times higher than that of the conventional PCR method.
authors.affiliation: Department of Clinical Chemistry, Faculty of Medical Technology, Mahidol University, 999 Phuttamonthon 4 Rd., Salaya, Nakhon Pathom 73170, Thailand; Nanoelectronics and MEMS Laboratory, National Electronics and Computer Technology Center, Pathumthani, Thailand.
authors.forename: Numfon
authors.initials: N
authors.lastname: Khemthongcharoen
authors.affiliation: Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Nakhon Pathom, Thailand.
authors.forename: Wijit
authors.initials: W
authors.lastname: Wonglumsom
authors.affiliation: Nanoelectronics and MEMS Laboratory, National Electronics and Computer Technology Center, Pathumthani, Thailand.
authors.forename: Assawapong
authors.initials: A
authors.lastname: Suppat
authors.affiliation: Nanoelectronics and MEMS Laboratory, National Electronics and Computer Technology Center, Pathumthani, Thailand.
authors.forename: Kata
authors.initials: K
authors.lastname: Jaruwongrungsee
authors.affiliation: Nanoelectronics and MEMS Laboratory, National Electronics and Computer Technology Center, Pathumthani, Thailand.
authors.forename: Adisorn
authors.initials: A
authors.lastname: Tuantranont
authors.affiliation: Department of Clinical Chemistry, Faculty of Medical Technology, Mahidol University, 999 Phuttamonthon 4 Rd., Salaya, Nakhon Pathom 73170, Thailand. Electronic address: chamras.pro@mahidol.ac.th.
authors.forename: Chamras
authors.initials: C
authors.lastname: Promptmas
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002771:Cholera / Q000175:diagnosis* / Q000382:microbiology; D002772:Cholera Toxin / Q000737:chemistry / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification*; D005517:Foodborne Diseases; D006801:Humans; D041241:Vibrio cholerae O1 / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity
chemical_list: D004269:DNA, Bacterial; D002772:Cholera Toxin
keywords: Biosensor; DNA sensor; Microcantilever; Piezoresistive microcantilever; Vibrio cholera; ctxA gene