Interação nanopartícula-clorofila: uma análise via espectroscopia óptica

Abstract

Advances in research into nanoparticles have led to great development of nanotechnology in diverse areas such as medicine, cosmetic, industries, communication technologies, among others. Silver nanoparticles (Ag NPs) are among the most widely produced and used nanomaterial due to their antimicrobial and antibacterial properties, allowing a wide range of commercial applications. Thereby, the increasing use of NPs should inevitably lead to the release and accumulation of these NPs into the environment, resulting in adverse effects on ecosystems. In this scenario it is also important to understand the risks of the interaction between NPs and plants, as a basic component of all ecosystems. In this context, the present study evaluated the interaction between Chlorophyll and Ag NPs with 10, 60 and 100 nm of diameter, over a wide range of nanoparticle concentrations, using optical techniques. The results reveal that the Chlorophyll Fluorescence is quenched in the presence of Ag NPs, and the observed suppression was nanoparticle concentration and size-dependent. In summary, by analysing the Stern-Volmer constant it was possible to determine that smaller nanoparticles have induced higher suppression. It was also observed that the pH variation induced a chlorophyll fluorescence quenching when acidic or basic solutions were prepared. Additionally, it was observed that plasmon resonance effect was partially responsible for observing quenching when the sample was excited at 405 nm,however, most of the observed quenching was caused by electron transfer process. The results also indicated that the short fluorescence lifetime was increased in the presence of nanoparticles, revealing an effective interaction between chlorophyll molecules and AgNPs.