“ESTUDO ESTRUTURAL DA CLOROFILA A COM NANO PARTÍCULAS DE PRATA: UMA ABORDAGEM COMPUTACIONAL"

Abstract

Over the decades, nanotechnology has been rapidly developed and applied in many fields, such as medicine, aesthetics, industry, communication technology, among others. Silver nanoparticles (AgNPs) are one of the most produced and used nanomaterials due to their antimicrobial and antibacterial capacity, allowing a wide range of commercial applications. With the increase in the use and disposal of products produced with nanotechnology, it is estimated that the accumulation of nanomaterials in the environment will be inevitable, with harmful effects on ecosystems. In this scenario, it is also important to understand the risks of interactions between nanoparticles and plants, which are fundamental components of the entire ecosystem and which are more potentially exposed to nanoparticles due to their constant interaction with air, soil and water. In plants, we find chlorophyll, which is among the most important molecules in nature, it is super versatile with activities that are not limited to just playing an important role in nature, but also in various human and artificial applications, whether as an indicator of herbicide concentration, biomaterial, biosensor or even in the production of hydrogen gas. In this context, the present work sought to evaluate the interaction between chlorophyll and AgNPs through molecular dynamics techniques. The theoretical study of the structure has been a challenge because as it presents a metallic ion coordinated to nitrogen, there are no force field parameters available in the literature. In order to carry out the study, it was necessary to construct the force field parameters. The same was done using the MCPB.py software, a Python-based metal center parameter constructor using the seminar method. With the generated model it was possible to obtain the computational study of the structure. Chlorophyll and pheophytin structures were optimized by the DFT method, B3LYP theory level with 6-31G base sets. The dynamics were performed in the software AMBER18, in the NpT ensembles for 200 ns. The nanoparticle was inserted through the INTERFACE force field, and its dynamics with chlorophyll was performed at 300 ns. With the results it was possible to observe significant differences in the chlorophyll structures after the molecular dynamics time, in addition the results obtained lead us to believe that the presence of AgNPs causes some kind of interference in the system. More conclusive results, as the experimental study suggests, demonstrating that AgNP may present a potential risk to plants will be needed in the future.

Keywords: Metallic íons parameterizations, Molecular Dynamic, MCPB.py, silver nanoparticle.