Electrocatalytic Activity of 3-Dimensional Ordered Macroporous Gold Electrode-Based Lactate Biosensors Platforms as a Function of Pore Layer Number

We report the electrocatalytic response of a lactate biosensor, based on a 3-dimensional ordered macroporous (3DOM) gold electrode, as a function of the pore layer number. The biosensor was developed by covalent immobilization of lactate oxidase (LOx) to a self-assembled monolayer of dithiobis-N-succinimidyl propionate (DTSP). The binding of DTSP to the gold surface was studied by X-ray photoelectron spectroscopy (XPS), indicating the existence of S?Au bonds. The DTSP coverage and the different steps followed in the construction of the biosensor were examined by electrochemical impedance spectroscopy (EIS). The catalytic response to a 14 mM lactate concentration, increased linearly with the pore layer number of the 3DOM gold electrode, reaching a value 3 times higher, than for polycrystalline gold electrodes, for 7.5 layers.