Bridged Rebar Graphene functionalized aptasensor for pathogenic E. coli O78:K80:H11 detection

Abstract

We report a novel fabrication method of functionalised Bridged Rebar Graphene (BRG) onto newly designed nanostructured aptasensor for label free impedimetric sensing of pathogenic bacteria E. coli O78:K80:H11. The chemical facilitated unscrolling of MWCNT and subsequent bridging with terephthalaldehyde (TPA) to form 3D-hierarchical BRG nanoconstruct exhibited synergistic effect by combining enhanced electrical properties and facile chemical functionality for stable bio-interface. The bacteria-DNA interactions were captured on BRG nanostructured electrode by using specific anti-E.coli DNA aptamer (K_d~ 14nM), screened by new in-situ developed SELEX method using phenylboronic acid on microtitre plate. The developed nanostructured aptasensor demonstrated a low detection limit and sensitivity of ~ 10¹cfu/mL towards E. coli O78:K80:H11 with a dynamic response range from 10¹ to 10⁶cfu/mL in water, juice and milk samples.

Keywords: Bacteria detection; Bridged Rebar Graphene; Cell-SELEX; DNA aptamer; Impedimetric aptasensor; Pathogenic E.coli.