The effects of glucose and glucose oxidase on the Uv-vis spectrum of gold nanoparticles: A study on optical biosensor for saliva glucose monitoring

In this study we have investigated the effect of glucose and glucose oxidase (GOD) on the absorption spectrum of gold nanoparticles (Au NPs) with 10 - 13 nm diameter, in order to improve optical methods of glucose monitoring using surface plasmon resonance of these particles. Different concentrations of glucose solution in water were prepared in the range of human saliva intensity. Two procedures are applied to study glucose effects on the particles; mixing the glucose to the nanocolloid and then adding the GOD, and reversely mixing the glucose and GOD solutions and then pouring in to the nanocolloid. Two different results were obtained that are analyzed based on optical properties. In each method, the effect of glucose and GOD on the size and Uv-vis spectrum of gold nanoparticles has been investigated. Results were interpreted by the physical concept of surface Plasmon resonance (SPR) of Au NPs. This study can open new insight about optical glucose sensing based on surface plasmon of metal nanoparticles.