Linker-free layer-by-layer self-assembly of gold nanoparticle multilayer films for direct electron transfer of horseradish peroxidase and H2O2 detection

Au nanoparticle (AuNP) multilayer films were fabricated by combining interfacial assembly and layer-by-layer assembly. The key point is that the procedure does not require assistance of organic linker molecules, thus providing a suitable platform for the modification of biological molecules. Direct electron transfer can easily take place between a glassy carbon electrode and horseradish peroxidase (HRP) molecules adsorbed on AuNP films. The current density of direct electron transfer was closely related to the layer number, m, and reached a maximum value for m = 4. The optimized HRP/AuNP multilayer film had a relatively rapid response and satisfactory selectivity for H2O2 detection. The linear range and the detection limit were 9.8 × 10−6 to 6 × 10−3 mol/L and ∼4.9 × 10−6 mol/L (S/N = 3), respectively.

► Gold nanoparticle (AuNP) multilayer films were fabricated via a linker-free layer-by-layer assembly. ► Direct electron transfer of horseradish peroxidase (HRP) absorbed on as-prepared AuNP multilayer films was enhanced. ► The optimized HRP/AuNP multilayer film had a relatively rapid response and satisfactory selectivity for H2O2 detection.