Biological and Agricultural Engineering Department, Louisiana State University Agricultural Center, United States.
ACS Nano. 2011 Dec 27;5(12):9313-25. doi: 10.1021/nn102845t. Epub 2011 Nov 10.
The goal of the study was to synthesize a surfactant made of α-tocopherol (vitamin E) and ascorbic acid (vitamin C) of antioxidant properties dubbed as EC, and to use this surfactant to make poly(lactic-co-glycolic) acid (PLGA) nanoparticles. Self-assembled EC nanostructures and PLGA-EC nanoparticles were made by nanoprecipitation, and their physical properties (size, size distribution, morphology) were studied at different salt concentrations, surfactant concentrations, and polymer/surfactant ratios. EC surfactant was shown to form self-assembled nanostructures in water with a size of 22 to 138 nm in the presence of sodium chloride, or 12 to 31 nm when synthesis was carried out in sodium bicarbonate. Polymeric PLGA-EC nanoparticles presented a size of 90 to 126 nm for 40% to 120% mass ratio PLGA to surfactant. For the same mass ratios, the PLGA-Span80 formed particles measured 155 to 216 nm. Span80 formed bilayers, whereas EC formed monolayers at the interfaces. PLGA-EC nanoparticles and EC showed antioxidant activity based on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay measurements using UV and EPR techniques, antioxidant activity which is not characteristic to commercially available Span80. The thiobarbituric acid reactive substances (TBARS) assay for lipid peroxidation showed that PLGA nanoparticles with EC performed better as antioxidants than the EC nanoassembly or the free vitamin C. Nanoparticles were readily internalized by HepG2 cells and were localized in the cytoplasm. The newly synthesized EC surfactant was therefore found successful in forming uniform, small size polymeric nanoparticles of intrinsic antioxidant properties.
本研究的目的是合成一种具有抗氧化性能的 α-生育酚（维生素 E）和抗坏血酸（维生素 C）表面活性剂，并称其为 EC，并使用这种表面活性剂制备聚（乳酸-共-乙醇酸）（PLGA）纳米粒子。通过纳米沉淀法制备了自组装的 EC 纳米结构和 PLGA-EC 纳米粒子，并研究了不同盐浓度、表面活性剂浓度和聚合物/表面活性剂比下它们的物理性质（尺寸、尺寸分布、形态）。结果表明，在氯化钠存在的情况下，EC 表面活性剂在水中形成自组装纳米结构，其尺寸为 22 至 138nm；而在碳酸氢钠存在的情况下，其尺寸为 12 至 31nm。对于 40%至 120%质量比的 PLGA 与表面活性剂，聚合物 PLGA-EC 纳米粒子的粒径为 90 至 126nm。对于相同的质量比，PLGA-Span80 形成的粒子粒径为 155 至 216nm。Span80 形成双层结构，而 EC 在界面处形成单层结构。基于 2,2-二苯基-1-苦基肼（DPPH）自由基清除测定法的 UV 和 EPR 技术，PLGA-EC 纳米粒子和 EC 均表现出抗氧化活性，这与市售的 Span80 不同。用于脂质过氧化的硫代巴比妥酸反应物质（TBARS）测定法表明，具有 EC 的 PLGA 纳米粒子作为抗氧化剂的性能优于 EC 纳米组装体或游离维生素 C。纳米粒子容易被 HepG2 细胞内化，并定位于细胞质中。因此，新合成的 EC 表面活性剂成功地形成了具有内在抗氧化性能的均匀、小尺寸聚合物纳米粒子。
