Centre for Fine Particles Processing and Nanotechnologies, Institute of Technical Sciences of the Serbian Academy of Sciences and Arts, Knez Mihailova 35/IV, 11000 Belgrade, Serbia.
Acta Biomater. 2014 Jan;10(1):151-62. doi: 10.1016/j.actbio.2013.08.030. Epub 2013 Aug 26.
A water-soluble antioxidant (ascorbic acid, vitamin C) was encapsulated together with poly(l-glutamic acid)-capped silver nanoparticles (AgNpPGA) within a poly(lactide-co-glycolide) (PLGA) polymeric matrix and their synergistic effects were studied. The PLGA/AgNpPGA/ascorbic acid particles synthesized by a physicochemical method with solvent/non-solvent systems are spherical, have a mean diameter of 775 nm and a narrow size distribution with a polydispersity index of 0.158. The encapsulation efficiency of AgNpPGA/ascorbic acid within PLGA was determined to be >90%. The entire amount of encapsulated ascorbic acid was released in 68 days, and the entire amount of AgNpPGAs was released in 87 days of degradation. The influence of PLGA/AgNpPGA/ascorbic acid on cell viability, generation of reactive oxygen species (ROS) in HepG2 cells, as well as antimicrobial activity against seven different pathogens was investigated. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay indicated good biocompatibility of these PLGA/AgNpPGA/ascorbic acid particles. We measured the kinetics of ROS formation in HepG2 cells by a DCFH-DA assay, and found that PLGA/AgNpPGA/ascorbic acid caused a significant decrease in DCF fluorescence intensity, which was 2-fold lower than that in control cells after a 5h exposure. This indicates that the PLGA/AgNpPGA/ascorbic acid microspheres either act as scavengers of intracellular ROS and/or reduce their formation. Also, the results of antimicrobial activity of PLGA/AgNpPGA/ascorbic acid obtained by the broth microdilution method showed superior and extended activity of these particles. The samples were characterized using Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, zeta potential and particle size analysis. This paper presents a new approach to the treatment of infection that at the same time offers a very pronounced antioxidant effect.
一种水溶性抗氧化剂（抗坏血酸，维生素 C）被包裹在聚（L-谷氨酸）-封端的银纳米粒子（AgNpPGA）内，然后封装在聚（乳酸-共-乙醇酸）（PLGA）聚合物基质中，并研究了它们的协同作用。通过溶剂/非溶剂系统的物理化学方法合成的 PLGA/AgNpPGA/抗坏血酸颗粒是球形的，平均直径为 775nm，粒径分布较窄，多分散指数为 0.158。AgNpPGA/抗坏血酸在 PLGA 中的包封效率被确定为>90%。在 68 天内释放了全部包裹的抗坏血酸，而在 87 天的降解过程中释放了全部的 AgNpPGAs。研究了 PLGA/AgNpPGA/抗坏血酸对 HepG2 细胞活力、活性氧（ROS）生成以及对七种不同病原体的抗菌活性的影响。3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐（MTT）测定法表明这些 PLGA/AgNpPGA/抗坏血酸颗粒具有良好的生物相容性。我们通过 DCFH-DA 测定法测量了 HepG2 细胞中 ROS 形成的动力学，发现 PLGA/AgNpPGA/抗坏血酸导致 DCF 荧光强度显著降低，与对照组细胞相比，在 5 小时暴露后降低了 2 倍。这表明 PLGA/AgNpPGA/抗坏血酸微球要么作为细胞内 ROS 的清除剂，要么减少其形成。此外，通过肉汤微量稀释法获得的 PLGA/AgNpPGA/抗坏血酸的抗菌活性结果表明，这些颗粒具有优越且延长的活性。使用傅里叶变换红外光谱、场发射扫描电子显微镜、透射电子显微镜、Zeta 电位和粒径分析对样品进行了表征。本文提出了一种治疗感染的新方法，同时具有非常明显的抗氧化作用。
