Biofunctionalized graphene oxide wrapped carbon nanotubes enabled microfluidic immunochip for bacterial cells detection

• Published in: Sensors and actuators. B, Chemical Vol. 255; pp. 2495 - 2503
• Main Authors: Singh, Chandan, Ali, Md. Azahar, Reddy, Venu, Singh, Dinesh, Kim, Cheol Gi, Sumana, G., Malhotra, B.D.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01-02-2018; Elsevier Science Ltd
• Subjects: Antibodies; Bacteria; Biosensors; Carbon; Carbon nanotubes; Chemical synthesis; E coli; Electron transfer; Electron transfer reactions; Functional groups; Graphene; Graphene oxide; Indium tin oxides; Microfluidic immunochip; Microfluidics; Multi wall carbon nanotubes; Nanotubes; Organic chemistry; Polydimethylsiloxane; Salmonella; Salmonella typhimurium; Sensitivity; Sensitivity enhancement; Sheets; Silicone resins; Synergistic effect; Tin oxides; Carbon nanotubes; Sensitivity; Graphene oxide; Synergistic effect; Microfluidic immunochip; Salmonella typhimurium
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2017.09.054

•Microfluidic Electrochemical immunosensor for Salmonella typhimurium detection designed using soft lithography technique.•Graphene Oxide (GO) wrapped caboxylated multiwalled carbon nanotubes (cMWCNTS) used as a transducer material for highly sensitive detection of Salmonella typhimurium.•Wrapping of cMWCNTs with GO leads to improved electrochemical performance of the composite as compared to GO, most probably due to the synergistic effect.•The functional groups available on GO and cMWCNTS were utilized for antibody functionalization using carbodiimide coupling using EDC-NHS chemistry results into the improved detection range.•The designed microfluidic immunosensor utilized to detect Salmonella typhimurium with negligible interference in presence of potential inteferent like E. Coli.
A sensitive and selective microfluidic immunochip was fabricated for detection of Salmonella typhimurium (S. typhimurium) bacterial cells. In this sensor, graphene oxide (GO) nano sheets wrapped carboxylated multiwalled carbon nanotubes (cMWCNTs) composite acted as a transducer material. The colloidal solution of GO-cMWCNTs composite was selectively deposited onto patterned indium tin oxide (ITO) electrode and sealed with polydimethylsiloxane (PDMS) micro channels. The S. typhimurium antibodies (StAb) were in situ biofunctionalized followed by EDC-NHS covalent chemistry via amidation reaction. The presence of abundant functional groups at the GO-cMWCNTs composite improved the loading of antibodies (StAb) against S. typhimurium leading to improved biosensing characteristics. Wrapping of cMWCNTs with GO resulted in superior electron transfer behavior enhancing the sensitivity (162.47μA/CFU−1/mLcm−2) almost two folds as compared to that based on GO (89.16μA/CFU−1/mLcm−2) sheets for bacterial cells detection. Besides this, GO wrapped cMWCNTs integrated microfluidics biosensor offered low detection limit as 0.376 CFU/mL and negligible interference due to presence of Escherichia coli (E. coli (O157:H7).