Ag Nanoplates Modified-Screen Printed Carbon Electrode to Improve Electrochemical Performances Toward a Selective H2O2 Detection

Sensors based on silver nanoplates (Ag NPT) colloidal solutions, deposited onto screen-printed carbon electrodes (SPCEs), were fabricated and characterized. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) analyses were carried out to test the sensor performances toward hydrogen peroxide (H2O2), selected as a model analyte of reactive oxygen species (ROS) involved in the regulation of metabolic/inflammatory diseases. H2O2 electrochemical sensing response, in terms of kinetic and sensitivity improvement, was wavelength-dependent and size-tunable. This was further confirmed by the simulation of electromagnetic field distributions based on finite difference time domain (FDTD) method. The electroanalytical behavior of the Ag NPT-modified electrodes in the presence of H2O2 has been studied by using the fabricated biosensor which demonstrated a sensitivity of 0.046 <inline-formula> <tex-math notation="LaTeX">$\mu \text{A}/\mu \text{M}$ </tex-math></inline-formula> for H2O2 concentrations lower than 100 <inline-formula> <tex-math notation="LaTeX">$\mu \text{M}$ </tex-math></inline-formula>. This work proposes a surface-engineering approach to design and develop electrochemical redox probes using Ag nanoparticles (Ag NPs) with particular nanoplates morphology.