Desenvolvimento de um dispositivo de detecção de cor de baixo custo baseado na correlação entre ressonância de plasmon e a cor das nanopartículas metálicas

Abstract

Theranostics agents often have nanoparticles (Np) as one of their components. Among the most commonly used are Np of noble metals that exhibit a plasmon resonance within the visible light spectrum that depends on the particle size, solution stability and dielectric constant of the medium. Eventually, when they precipitate, there is a change in plasmon resonance and, consequently, in staining, in addition to becoming unusable according to regulatory agencies. A simple device that might be able to connect the plasmon resonance data to the color displayed by the colloid in order to determine the drug's validity could be of great help. Due to the evolution of sensors and with the knowledge of plasmon resonant frequencies of metal Np, it is possible to construct such a device. Thus, in this work, gold nanoparticles (AuNPs) of different sizes were synthesized and their absorption spectra were measured. In the development of the project, the use of an RGB sensor was chosen due to its sensitivity in differentiating the colors of the AuNPs. Accordingly, a prototype was built to position the sensor and collect the data. Finally, the absorption spectra were compared with the obtained colors, and the device was calibrated. As a result, a standard was established using an affordable RGB color reader device, which allows evaluating the quality of a AuNP sample used as a sensor.