Label‐free, PCR‐free DNA Hybridization Detection of Escherichia coli O157 : H7 Based on Electrochemical Nanobiosensor

Abstract

1IntroductionFoodborne infections are an important public health concern worldwide. Escherichia coli O157 :H7i saparto ft he enterohemorrhagic group of E. coli (EHEC). Clinical symptoms of patients infected with E. coli O157 :H7h ave aw ide range and diagnosis of the symptoms is difficult. Thep athogen causes diarrhea and hemolytic uremic syndrome (HUS) in human beings.H emolytic uremic syndrome (HUS), al ife threatening complication that causes kidney failure,i sd evelopedb ya bout 10 %o fp atients, mostly in elderly people and children. So the exploitation of new methods for rapid and sensitived etection of such microorganism predicates significance to the safety in food or water supplies [1,2].C onventional detection methods for bacterialp athogens are the culture and colony counting,i mmunological techniquesa nd polymerase chain reaction( PCR). In addition to culture based methods, other techniques such as immunoassays, enzyme assays,a nd nucleic acid probe assays have been exploited for the identification of some foodborne pathogens.U nfortunately,d espite being powerful and errorproof approaches,m ost of them are laborious,c omplex, and time consuming,a nd they are not specific enough towards theirt argets [3,4].E nrichment, immunomagnetic separation, plating on selective media, and the agglutination of O157 antigenf ollowedb yP CR detection of virulence genes for confirmation, are the main strategies which are generally used for the isolation and identification of E. coli O157 in food and feces [5].T he nanobiosensors offers everala dvantages in comparison to the mentioned methods;l imited hands-on time,i mproved detectability,h igh-throughput screening, the possibility of real-time analysis,l abel-freed etection,s impler nucleic acid assays, and finally,t he faster and cheaper process has triggered ag reat interest toward nanobiosensor techniques [6].Adiagnostic label-free,P CR-free nanobiosensor could be an extremely powerful and rapid tool for detecting microorganisms in environmental and food samples,a sw ell as for clinical diagnosis of microbial infectionsa nd genetic diseases.Due to its tremendous molecular recognition potential, DNAi se specially well suited to biosensing applications [7].D NA biosensors could detect the DNAs equences via the hybridization to the complementary single stranded sequences,a nd offer ap romising approach for rapid, sen-Abstract:Asimple and sensitiven anobiosensor was developedf or diagnosingl abel-free,P CR-free of rfbE gene in Escherichia coli O157 :H7r eal sample.T he Au nanoparticles modified electrode (Au nano ME) was prepared by electrodepositiont echnique.T he single-strandedD NA probeswere immobilized through the chemisorptions process on Au nano ME (ssDNA/Au nano ME). Electrochemical impedance spectroscopy (EIS) techniqueh as been used to investigate the hybridization and sensing properties. Using electrochemical impedance spectroscopy (EIS) technique,t he charge-transferr esistance (R ct )v alues were raised by immobilization of the DNAp robea nd after the hyb...

Electrochemical nucleic acid-based sensors for detection of E. coli and Shiga toxin-producing E. coli (STEC) – Review of the recent developments

“…Recent studies, however, concluded that the presence of this gene is not essential to cause a severe illness, showing that not all STEC causing illness outbreaks had this gene present (EFSA Panel on Biological Hazards, 2020). Less often, other virulence factors were used such as the rfbE gene coding for an O-antigen synthesis for O157 serotype, shown in the work of Minaei et al (2016). An ideal STEC detection technique should, however, focus on all serotypes which potentially cause the infection.…”

Ultrasensitive Electrochemical Impedance Detection of Mycoplasma agalactiae DNA by Low-Cost and Disposable Au-Decorated NiO Nanowall Electrodes

“…Among the different devices developed so far, electrochemical sensors are very advantageous due to their robustness, miniaturization, sensitivity, and fast response along with low-cost/energy/mass characteristics and great potential as PoC devices intended for commercialization. , The working electrode is the core component of any electrochemical sensor, and for DNA sensors, it is where probe ssDNA is immobilized via physical absorption, self-assembly, or covalent bonds (as in the case of thiolated probe ssDNA and Au electrodes). Indeed, the working electrode determines the ultimate properties of the sensor. , Upon hybridization of probe ssDNA with the complementary sequence, an electrochemical signal is generated whose amplitude defines the sensitivity of the sensor . Various electrochemical techniques have been used to enhance the hybridization signal, including voltammetric, amperometric, coulometric, and impedimetric techniques .…”

“…Indeed, the working electrode determines the ultimate properties of the sensor. 13,14 Upon hybridization of probe ssDNA with the complementary sequence, an electrochemical signal is generated whose amplitude defines the sensitivity of the sensor. 9 Various electrochemical techniques have been used to enhance the hybridization signal, including voltammetric, amperometric, coulometric, and impedimetric techniques.…”

Label-Free Detection of E. coli O157:H7 DNA Using Light-Addressable Potentiometric Sensors with Highly Oriented ZnO Nanorod Arrays

“…The fast development of microand nanofabricated devices has opened up an exciting realm for the development of a new generation of label-free DNA biosensors. For instance, the label-free detection of E. coli O157:H7 DNA has been reported using piezoelectric sensors and electrochemical biosensors [5,[15][16][17]. More recently, field-effect devices (FEDs) have offered a promising direct electrical readout for label-free DNA detection [18][19][20][21].…”