Interação entre nanopartículas de ouro e extratos foliares da Vicia faba: uma análise via espectroscopia óptica

Abstract

In the present work, analyses were performed using leaf extracts constituted of the main photosynthetics pigments of the plant Vicia faba, from which it was possible to isolate the chlorophyll and pheophytin by separation column chromatographic method, which were characterized by optical techniques. Additionally, the interactions were valued between the molecules porphyrin (Chlorophyll and pheophytin) and nanoparticles of gold (AuNP) of 5, 10 and 20 nm of diameter, from the analyses of Absorption UV-Vis, Molecular Fluorescence and time of life of luminescence. One checked that the molecules porphyrins presented reduction or increase in the fluorescence intensity, in accordance with the studied conditions, besides the reduction in the times of life of fluorescence of the molecules in the presence of the AuNPs. The effects were significantly more evident for the samples consisting of Pheophytin, suggesting a less affinity of the Chlorophyll to interact with the AuNPs, when compared with the porphyrin uncomplexed. Generally, it was determined that the AuNPs have great potential to interfere with the plant photosynthesis process, given the ability to interact strongly with the photosynthetic pigments that are critical in chemical production process in plants, highlighting a potential risk of toxicity the metal nanoparticles may have on the environment.