Electrochemical genosensor based on three-dimensional DNA polymer brushes monolayers

A new approach to the three dimensional integration of short DNA strands at gold electrode surfaces via the in situ formation of DNA-acrylamide conjugates is presented. Surface initiated atom transfer radical polymerisation was employed to grow acrylamide brushes co-polymerised in the presence of acrylamide modified DNA probes. This strategy was demonstrated for the realisation of biofunctionalised thin polymer films capable of binding its complementary 105-base DNA amplicon. The synthesised brushes were characterised using atomic force microscopy, attenuated total reflectance spectroscopy and electrochemical impedance spectroscopy. Once characterised, the polymer brushes were applied to the quantitative detection of target DNA using an enzyme labelled reporter DNA probe in a sandwich-type format.

► Achievement of DNA-co-polymer brushes at electrode surfaces via SI-ATRP.
► Confirmation of the incorporation of short DNA by attenuated total reflectance FTIR.
► Characterisation of each surface modification step by EIS.
► Estimation of the polymer layer thickness by atomic force microscopy.
► Electrochemical detection via enzymatic labelling and fast amperometry.