Biossíntese de nanopartículas de prata com própolis verde e sua atividade antifúngica

Abstract

Nanotechnology has been widely used in the development of new antifungal therapies, among which silver nanoparticles (AgNPs) have stood out. Green propolis, collected by Africanized bees from the buds of the field rosemary (Baccharis dracunculifolia), is valued for its distinctive chemical composition. Despite the recognized effectiveness of AgNPs against various pathogens, there are still few studies on AgNPs modified with green propolis extract and their potential antifungal applications. This study proposes the biosynthesis, characterization, and evaluation of the antifungal activity of AgNPs modified with green propolis extract. Using a 2³ factorial design, the study sought to determine the ideal conditions for the synthesis of AgNPs, considering three variables: silver nitrate (AgNO3) concentration (250 and 500 μM), stirring speed (500 and 1500 rpm), and green propolis extract (EPV) concentration (240 and 480 μg.mL-¹). The formation of AgNPs was confirmed by the emergence of the characteristic silver surface Plasmon resonance band in the UV-Visible spectrum and by the color change of the solution. Analysis by Dynamic Light Scattering (DLS) showed that most particles had sizes between 10 and 100 nm, with a peak intensity around 40-50 nm. Furthermore, the adsorption of phenolic and flavonoid compounds presents in the green propolis extract resulted in a negative average Zeta Potential of 41 to 68 mV, suggesting a high stability of the colloidal suspension. The AgNPs modified with green propolis showed effective antifungal activity against Candida albicans in in vitro studies. The results indicated that the silver nitrate concentration influences the suspension stability and the ability of AgNPs to resist agglomeration and sedimentation. These findings highlight the potential of AgNPs modified with green propolis extract for future applications in biological and industrial environments.