Facile Fabrication of a Sensor with a Bifunctional Interface for Logic Analysis of the New Delhi Metallo-β-Lactamase (NDM)-Coding Gene

Surface functionalization has attracted considerable interest from researchers because of its capability for facilitating the interface communication between an energy transducer and a biological system. We report newly synthesized N-(4-aminobenzoyl)-N'-(4-maleimidobenzoyl)1,2-ethylenediamine (AME) to promote the modification of the surface with thiolated DNA and 3-((4-aminophenyl)dimethylammonio)propane-1-sulfonate (APSB) for the facile formation of a bifunctional interface forming an antifouling surface. Through the formation of diazonium ion, electrochemically reductive deposition of the two arylamines can fabricate simultaneously and effectively a bifunctional surface on a gold electrode and install a DNA probe to form a sensor; the sensor was applied to detect three genetic fragments of the New Delhi Metallo-beta-Lactamase (NDM)-coding gene. Effects of the diazotization and the conditions of electrochemical deposition upon the sensing signals were investigated in connection with enumerating the accessible maleimide groups and assessing the diffusion resistance of the electroactive indicator. The detection limit given by the diazonium-constructed system was improved to attain the level of 54 pM, an advance over a conventional self assembled monolayer.