Resumen: This study describes the first steps towards the design of an enzymatic optical (nano)biosensor for the determination of glucose. The aim of this work is to relate the optical properties of gold nanomaterials with glucose concentration. In order to achieve this goal, the redox properties of FAD cofactor of the glucose oxidase enzyme were used. During the enzymatic reaction between glucose oxidase and glucose, the FAD cofactor is reduced to FADH2. A gold precursor in oxidation state 3+ is used to reoxidize the enzyme which at the same time is reduced to gold in oxidation state 0. Gold in oxidation state 0 can be developed into two different types of nanomaterials: gold nanoparticles (AuNPs) or gold nanoclusters (AuNCs). These nanomaterials have different optical properties which could be related to the glucose concentration. On the one hand AuNPs exhibit absorption properties due to surface plasmon resonance (SPR). On the other hand AuNCs are composed by only few atoms, its size is around 2 nm or less and displays fluorescence. The intensity of SPR of gold nanoparticles has been successfully related to the glucose concentration. In addition, kinetics studies have shown a relationship between the velocity at which the fluorescent intensity of AuNCs increases and the glucose concentration.