Electrochemical impedance immunosensor for rapid detection of stressed pathogenic Staphylococcus aureus bacteria

Abstract

In this work, we report the adaptation of bacteria to stress conditions that induce instability of their cultural, morphological, and enzymatic characters, on which the identification of pathogenic bacteria is based. These can raise serious issues during the characterization of bacteria. The timely detection of pathogens is also a subject of great importance. For this reason, our objective is oriented towards developing an immunosensing system for rapid detection and quantification of Staphylococcus aureus. Polyclonal anti-S. aureus are immobilized onto modified gold electrode by self-assembled molecular monolayer (SAM) method. The electrochemical performances of the developed immunosensor were evaluated by impedance spectroscopy through the monitoring of the charge transfer resistance at the modified solid/liquid interface using ferri-/ferrocyanide as redox probe. The developed immunosensor was applied to detect stressed and resuscitate bacteria. As a result, a stable and reproducible immunosensor with sensitivity of 15 kΩ/decade and a detection limit of 10 CFU/mL was obtained for the S. aureus concentrations ranging from 10(1) to 10(7) CFU/mL. A low deviation in the immunosensor response (±10 %) was signed when it is exposed to stressed and not stressed bacteria.

Electrochemical Detection of Pathogenic Bacteria—Recent Strategies, Advances and Challenges

“…One of the key advantages of electrochemical sensing technology is its sensitivity and hence detection limits as low as one or very few culture forming units (CFU) have been achieved . However, it has to be questioned if detecting infections at such low bacterial counts will truly be beneficial.…”

“…One of the key advantages of electrochemical sensing technology is its sensitivity and hence detection limits as low as one or very few culture forming units (CFU) have been achieved. [18,24,29,45,60,63,65,70] However, it has to be questioned if detectingi nfections at such low bacterialc ounts will truly be beneficial. It has recently been reported, [71] with the example of urinary tract infections (UTIs), that diagnosing patients on the basis of CFU of less than 10 5 per mL, resulted in treatment of non-clinically significant UTIs and inappropriate use of antibiotics.…”

“…The use of thiol‐chemistry to introduce a bio‐recognition element for the specific detection of pathogens has been reported in the past and remains a useful method in recent literature for the specific immobilization of bacteria for further analysis by electrochemistry . Bekir et al.…”

“…The use of thiol-chemistry to introduce ab io-recognition element for the specific detection of pathogens has been report-ed in the past [17] and remains au seful method in recent literature for the specific immobilization of bacteria for furthera nalysis by electrochemistry. [18] Bekir et al constructed self-assembled monolayers (SAMs) on gold electrodes and successfully SWCNTs :s ingle-walled carbon nanotubes;M WCNTs :m ulti-walled carbon nanotubes EIS: electrochemical impedance spectroscopy;D PV:d ifferential pulse voltammetry;A uNPs:g oldn anoparticles;A gNPs: silver nanoparticles;I TO:i ndium tin oxide;E CL:e lectrochemiluminescence;L OC:l ab-on-a-chip;T MPD: N,N,N',N'-tetramethyl-para-phenylene-diamine;G QDs:graphene-quantum-dots detected S. aureus at the electrode using electrochemical impedances pectroscopy.A ni ncrease in the charget ransfer resistance( "off signal")c an be ag ood indicator fort he presence of bacteria on the electrode surface. However,c areful attention needs to be paid to assure that the signal blockage is indeed due to target bacteria and not due to impurities or nonspecific binding events.…”

Binding strategies for capturing and growing Escherichia coli on surfaces of biosensing devices

“…To test similar structures to those used with Au or GaAs surfaces functionalized with carboxyl-thiol linkers [35], COOH plates were used with activators EDC/NHS to covalently link the carboxyl group of the wells with an amine group from the Ab. For this structure, 50 µL of fresh solutions of 800 mM EDC in water and 200 mM NHS in water were used to activate the carboxyl group in the wells for 1 h at room temperature (RT).…”