Layered Xerogel Films Incorporating Monolayer‐Protected Cluster Networks on Platinum‐Black‐Modified Electrodes for Enhanced Sensitivity in First‐Generation Uric Acid Biosensing

Abstract

AbstractAmperometric uric acid (UA) biosensing schemes incorporating networks of alkanethiolate‐protected gold nanoparticles, monolayer protected clusters (MPCs), and platinum black (Pt‐B) electrode modification through the layer‐by‐layer construction of xerogels are investigated. MPC doping and Pt‐B augmentation are implemented within hydroxymethyltriethoxysilane xerogel bilayers at platinum electrodes. The first xerogel adlayer is doped with an MPC network and houses uricase for the enzymatic reaction required for first‐generation schemes. Polyluminol–aniline and polyurethane are used as selective/stabilizing interfacial layers. The sensing performance with and without Pt‐B and/or MPC doping is assessed by amperometry with standardized UA injections. The use of each individual material results in an enhancement of UA sensitivity compared with analogous films without these materials. The use of Pt‐B and MPC doping in concert results in a biosensor design with the highest observed UA sensitivity (0.97 μA mm−1) and fast, linear responses over physiologically relevant UA concentrations. Enhancement is attributed to Pt‐B providing increased electrode surface area and integration into the xerogel for greater electronic coupling of the MPC network and more efficient reporting of H2O2 oxidation. The findings have implications for advancing clinical in vivo sensing devices that require scalability or additional biocompatibility layering, both of which would benefit from signal enhancement strategies.