Synergistic effect of 2D material coated Pt nanoparticles with PEDOT polymer on electrode surface interface for a sensitive label free Helicobacter pylori CagA immunosensing.

Helicobacter pylori (H. pylori) immunosensor based on platinum nanoparticles/poly(3,4-ethylenedioxythiophene)/reduced graphene oxide (Pt/PEDOT/red-GOx) modified gold electrode (Au-ET) was stepwise fabricated for the detection of cytotoxin-associated gene A antibody (CagA antibody). H. pylori is a microaerophillic and a Gram-negative bacteria that causes gastric ulcer leading eventually to adenocarcinoma (gastric cancer) in the later stage. H. pylori colonizes inner lining of human stomach. The developed diagnostic sensing interface would allow H. pylori (stomach infection) detection in early stage and would be a great contribution in clinical laboratories. In order to fabricate the immunosensor, CagA antigen was immobilized over the Pt/PEDOT/red-GOx modified Au-ET. Afterwards, the modified electrode was used for immuno-sensing of H. pylori specific Cag A antibodies in serum. At lower voltage the modified Pt/PEDOT/red-GOx/Au-ET shows an amplified sensing at the interface that makes the sensor more sensitive and specific. CagA is a virulence factor produced by H. pylori was determined by sudden decrease in the current. The laboratory synthesized nano composites were characterised by Scanning Electron Microscopy (SEM) and Atomic force microscopy (AFM) studies. The sensor had excellent linear range of 0.1 ng/ml to 30 ng/ml by limiting the detection range up to 0.1 ng/ml. Moreover, the novel immunosensor formed had good accuracy, precision and reliability. The immunosensor also showed an excellent storage stability by retaining 60-70% of its initial activity until 60 days kept at 4 °C. Highly sensitive interface of CagA antigen@Pt/PEDOT/red-GOx/Au-ET shows a promising future for H. pylori detection in diagnosis of stomach ulcer and stomach cancer.