pH and non-enzymatic glucose response at ultra-low concentration using submicrochannel heterogeneous membrane

The construction of solid nanochannel-based biosensor with submicron pore size has great significance to the analysis of biomolecule with high sensitivity and low detection limit. In this paper, a submicrochannel heterogeneous membrane with asymmetric geometry is prepared as the base by combining thermo-crosslinked hydrophobic conducting polymer and porous anodic aluminium oxide channel (AAO) with submicron pore size (269 nm). After the polydopamine-Au multilayer assembly, a large number of Au nanoparticles with adjustable size (∼10 and 89 nm) and density are in situ generated and fixed on the inner wall of AAO. Then 4-mercapto phenylboric acid with high density is grafted through Au-S bond to construct the submicrochannel heterogeneous membrane with the characteristic of ion current rectification in response to pH and saccharide. Benefit from the blocking effect of hydrophobic conducting polymer and the multilayer assembly of polydopamine-Au, the current of background response by the membrane device is effectively reduced, the ion current rectification strength can be effectively regulated in the range of pH 3–9, and the response to ultra-low glucose concentration without enzyme is achieved in the linear range of 1 pM-0.1 μM. A universal substrate platform is provided for the construction of solid nanochannel-based biosensor with submicron pore size.