Unveiling Antimicrobial Properties and Crystallization Induction in PLA Using α-Ag<sub>2</sub>WO<sub>4</sub> Nanoparticles
Letícia A. Onue, Lara Kelly Ribeiro, Mariana Ottaiano Gonçalves, E. Longo, Cristina Paiva de Sousa, Marcelo Assis, Sandra Andréa Cruz
Abstract
In this study, α-Ag 2 WO 4 nanoparticles were synthesized and then immobilized within the poly(lactic acid) (PLA) matrix at varying concentrations (0.5, 1.0, and 3.0%). X-ray diffraction revealed the successful incorporation of α-Ag 2 WO 4 nanoparticles into the PLA matrix without the presence of undesired phases. Furthermore, crystallinity results indicated that the particles did not have the potential to act as nucleating agents under quiescent conditions, but induction in crystallization was observed under nonquiescent conditions. Rheology analysis demonstrated an increase in complex viscosity values for all samples containing α-Ag 2 WO 4 when compared to those of the pure polymer, indicating good dispersion and distribution. The antimicrobial activity of the composites was particularly effective against Escherichia coli and at higher concentrations for Staphylococcus aureus and Candida albicans after 16 h of contact. The antimicrobial efficiency was associated with the ability of α-Ag 2 WO 4 to generate reactive oxygen species (ROS) and the ionic release of Ag +, causing irreversible damage to the membranes of these microorganisms. This type of study sheds light on the development of PLA platforms with potential antimicrobial activity and increased crystallization capacity under the employed processing conditions.