Nanopartículas de óxido de cobre (II): síntese, estabilização, revestimento com os polissacarídeos do cogumelo Agaricus blazei Murill e atividades biológicas

Abstract

Nanoparticles are materials that exist on the nanometric scale, corresponding to the billionth part of a meter. These materials exhibit remarkable properties compared to their macroscopic counterparts, standing out for their electrical, optical, magnetic, catalytic, and antimicrobial behaviors. Another material of interest, derived from the Brazilian mushroom Agaricus blazei Murill, also displays noteworthy characteristics. Polysaccharides extracted from this mushroom have been reported to possess immunomodulatory, antitumor, and anti-herpetic properties, among others. Therefore, this study aimed to integrate the distinctive features of both materials through synthesis and coating processes. The synthesized nanoparticles were characterized using a range of analytical techniques and subsequently assessed for their biological activity. Two copper precursor salts were employed: CuSO₄·5H₂O and CuCl₂·2H₂O. The resulting materials were characterized by ultraviolet–visible (UV–Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and zeta potential measurements. Thermogravimetric analysis (TGA) was also performed, alongside antifungal assays against Candida albicans and Candida parapsilosis, cytotoxicity tests on RAW 264.7 macrophages, and acute toxicity evaluation in adult zebrafish. The findings revealed that nanoparticles synthesized from CuSO₄·5H₂O exhibited superior characteristics, presenting higher purity than those obtained from CuCl₂·2H₂O. The crystallite sizes estimated for CuSO₄·5H₂O-derived nanoparticles were approximately 10.12 nm for uncoated samples and 5.76 nm for samples coated with mushroom polysaccharides. In contrast, nanoparticles synthesized using CuCl₂·2H₂O exhibited crystallite sizes of 13.24 nm (uncoated) and 19.27 nm (coated). Polysaccharide coating significantly enhanced the stability of the nanoparticles, both in powder form and in aqueous suspension, as confirmed by SEM, AFM, DLS, and zeta potential analyses. Furthermore, CuSO₄·5H₂O-based nanoparticles displayed stronger antifungal activity against C. albicans and C. parapsilosis. The polysaccharide coating effectively preserved the antifungal performance of the nanoparticles, suggesting that these biopolymers act as efficient stabilizing agents without impairing biological activity. Due to their pronounced biological performance and stability, these nanoparticulate systems hold substantial scientific and technological relevance, offering promising potential for pharmaceutical applications. The improvement and optimization of such materials therefore represent a compelling and valuable avenue for the development of innovative therapeutic strategies.