Glucose sensing on reproducible and tunable plasmonic nanostructures formed on annealed coverslips coated with thin layers of gold and indium tin oxide

Abstract

In the present study, coverslips were used as solid support for the synthesis of nanoparticles (NPs) through two annealing protocols at 550 °C: (i) monometallic Au NPs (Au-4 nm/3 h and Au-4 nm/8 h NPs) (named one step annealing) and (ii) ITO-Au hybrid 16 h NPs (ITO/Au and Au/ITO NPs) (named two steps annealing). The obtained active NPs were investigated for their stability performances in aqueous saline buffer (PBS buffer) and LSPR sensitivity related to the changes of refractive index (RI) in air and glucose solutions. The experiments proved the great stability of annealed Au-4 nm/8 h NPs, ITO/Au /16 h NPs, and Au/ITO/16 h NPs in the presence of PBS buffer. Moreover, LSPR sensing of low (0.2–3 mg/mL) and high glucose concentrations (25 % (w/v)) in wet and dry conditions on Au-4 nm/8 h NPs and ITO/Au NPs coated coverslips of reproducible sensitivity to the environmental RI changes over time is also reported.