Linker-free layer-by-layer self-assembly of gold nanoparticle multilayer films for direct electron transfer of horseradish peroxidase and H 2O 2 detection

Abstract

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 H 2O 2 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.