Síntese e caracterização de nanopartículas de selênio (SeNPs) e selênio-Cobre (SeCuNPs) com potencial fotoprotetor e antioxidante

Abstract

Selenium-containing nanoparticles (NPs) have been extensively studied due to the therapeutic properties associated with various systems. Regarding biotechnological applications there is still little information available about selenium and selenium-copper NPs. The present work aimed to synthesize and characterize selenium (SeNPs) and selenium-copper (SeCuNPs) nanoparticles to evaluate their antioxidant and photoprotective potential. To this end, the NPs were synthesized using the stabilizers chitosan (QUI) and polyvinyl alcohol (PVA). The syntheses were adapted from procedures already described in the literature. The characteristics of the NPs were evaluated by transmission electron microscopy (TEM); energy dispersive X-ray spectrometry (EDX); dynamic light scattering (DLS); Fourier transform infrared molecular absorption spectroscopy (FTIR) and UV-vis molecular absorption spectroscopy. Tests were performed to evaluate the antioxidant capacity, by means of ABTS●+, DPPH●, FRAP methods; sun protection factor (SPF) and tyrosinase inhibition; and in vivo toxicity evaluation, using Drosophila melanogaster as a model. Characterization data confirmed the formation and identity of the synthesized materials. Employing TEM, the SeCuNPs in the two stabilizers were found to be smaller in size than the SeNPs, with a size reduction from 94 and 78 nm to 36 and 35 nm in QUI and PVA, respectively. By means of the EDX technique, the presence of Se and Cu in SeCuNPs was verified, proving to be a bielementary material. The FTIR spectra of the SeNPs and SeCuNPs showed characteristic profiles of the stabilizing agents, proving their presence on the surface of the NPs. The UV-vis absorption spectra showed the characteristic absorption bands of such materials, with absorption at 260 and 250 nm for the SeNPs stabilized in QUI and PVA, respectively, and at 240 and 900 nm for the SeCuNPs in both stabilizers. Regarding the applications, both NPs showed high antioxidant activity, superior to the standards trolox®, ascorbic acid and quercetin. The NPs presented approximately twice the SPF value when compared to 2-hydroxy-4-methoxybenzophenone (BZF-3), compound present in commercial formulations, being the SPF values of SeCuNPs higher than SeNPs. In tyrosinase inhibition assays SeNPs exhibited IC50 values of 4.8 and 10.1 mg L-1, for SeNPs_QUI and SeNPs_PVA, respectively, while SeCuNPs were able to inhibit the enzyme only at concentrations higher than 50 mg L-1. Toxicity assays with Drosophila melanogaster model evidenced that both NPs exhibit toxicity at concentrations ≥ 50 mg L-1 indicating high tolerance of organisms to the evaluated NPs. Such results revealed that SeNPs and SeCuNPs are promising for the applications proposed in this work.