Characterization of rhodamine loaded PEG-g-PLA nanoparticles (NPs): Effect of poly(ethylene glycol) grafting density
Characterization of rhodamine loaded PEG-g-PLA nanoparticles (NPs): Effect of poly(ethylene glycol) grafting density
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DOI：
10.1016/j.ijpharm.2011.02.039
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发表时间：
2011-06-15
影响因子：
5.8
通讯作者：
Hildgen, Patrice
中科院分区：
文献类型：
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作者：
Essa, Sherief;Rabanel, Jean Michel;Hildgen, Patrice
在我们之前的研究中，开发并表征了 PEG-g-PLA 纳米颗粒。本工作的目的是研究 PEG 接枝密度（插入聚（D，L）-丙交酯、PLA 骨架上的 PEG 百分比）对 PEG-g-PIA NP 的理化和生物学特性（主要是血浆蛋白结合和体外巨噬细胞摄取）的影响。负载罗丹明 B (RHO) 的纳米粒子是通过 O/W 乳液溶剂蒸发方法，由不同 PEG 接枝密度（1%、7% 或 20% mol/mol 乳酸单体）的 PIA 和 PEG-g-PLA 共聚物 1:1（wt/wt）混合物制备而成。这些纳米颗粒的特征包括其形态、尺寸、表面电荷、负载效率和罗丹明释放。通过动态光散射技术定性研究了不同纳米粒子表面的蛋白质吸附程度。此外，通过共聚焦激光扫描显微镜 (CLSM) 研究了将 RAW 264.7 细胞与负载罗丹明的 PEG-g-PIA 和 PLA 颗粒一起孵育后的体外巨噬细胞摄取。 RAW 264.7 细胞与不同浓度的负载罗丹明的 PLA 或聚乙二醇化 NP 在 37 ℃ 下孵育 24 小时后吞噬的 NP 量也通过荧光光谱法测定。与新鲜制备的 NP 悬浮液相比，所有冻干 NP 的直径均在 300-400 nm 范围内，表明冻干后颗粒聚集。发现罗丹明的 % EE 在 10% 至 68% wt/wt 之间，具体取决于 PEG 接枝密度。 PEG 在 PIA 主链上的接枝密度越高，包封效率越高。所有聚乙二醇化纳米粒子均表现出较低的 zeta 电位（接近于零）值。体外释放分析表明，在生理 pH 值下，罗丹明以非常慢的速度从所有纳米颗粒中泄漏，因此适合使用 RAW 264.7 细胞进行成像和摄取研究。细胞增殖测定显示，不同 PEG 接枝密度的所有 PEG-g-PLA NP 均具有良好的耐受性，并且对 RAW 264.7 细胞没有毒性。细胞对纳米颗粒的摄取主要取决于聚合物类型以及 PEG 接枝密度。与巨噬细胞系中的 PIA NP 相比，接枝共聚物 NP 导致巨噬细胞摄取程度较低。 PEG接枝密度越高，巨噬细胞对NP的摄取越低。当 PEG 接枝密度为 7% mol/mol 乳酸时，所有研究浓度的纳米颗粒摄取量均达到最低。当纳米颗粒中的 PEG 接枝密度增加到 7% 以上时，纳米颗粒的吞噬作用没有显着降低。因此，本研究表明，设计适合药物输送应用的隐形 PEG-g-PLA NP 所需的最佳 PEG 密度可能在 4% 至 7% 之间变化。 (C) 2011 Elsevier B.V. 保留所有权利。
In our previous study, PEG-g-PLA nanoparticles were developed and characterized. The aim of the present work is to investigate the effect of PEG grafting density (% PEG inserted onto poly(D, L)-lactide, PLA backbone) on both physicochemical and biological properties (mainly plasma protein binding and in vitro macrophage uptake) of PEG-g-PIA NPs. Rhodamine B (RHO) loaded NPs were prepared from a 1:1 (wt/wt) blend of PIA and PEG-g-PLA copolymer of varying PEG grafting density (1, 7, or 20% mol/mol of lactic acid monomer) by an o/w emulsion solvent evaporation method. These NPs were characterized with regard to their morphology, size, surface charge, loading efficiency, and rhodamine release. The extent of protein adsorption to the surface of different NPs was qualitatively investigated by dynamic light scattering technique. Additionally, the in vitro macrophage uptake following incubation of RAW 264.7 cells with rhodamine loaded PEG-g-PIA and PLA particles was investigated by confocal laser scanning microscopy (CLSM). The amount of NPs phagocytosed following incubation of RAW 264.7 cells with different concentrations of rhodamine loaded PLA or pegylated NPs for 24 h at 37 degrees C was also determined by fluorescence spectroscopy. ALL lyophilized NPs showed larger diameter in the range of 300-400 nm compared to freshly prepared NPs suspension indicating particle aggregation upon lyophilization. % EE of rhodamine was found to be between 10% and 68% wt/wt depending on PEG grafting density. The higher the grafting density of PEG over PIA backbone, the more the entrapment efficiency. All pegylated NPs showed low zeta potential (close to zero) values. In vitro release analysis revealed that rhodamine leaked from all nanoparticles at a very slow rate at physiological pH, thus making it suitable for both imaging and uptake studies with RAW 264.7 cells. All PEG-g-PLA NPs of different PEG grafting density were well tolerated and exhibited no toxicity to RAW 264.7 cells as seen by cell proliferation assays. Cellular uptake of NPs was mainly dependent on polymer type as well as PEG grafting density. Grafted copolymer NPs resulted in lower degree of macrophage uptake compared to PIA NPs in macrophages cell lines. The higher the PEG grafting density, the lower the uptake of NPs by macrophage cells. Minimum NPs uptake for all the investigated concentrations was achieved when the PEG grafting density was 7% mol/mol of lactic acid. When increasing the PEG grafting density in the nanoparticles above 7%, no significant reduction in NPs phagocytosis was achieved. Thus, this study shows that the optimal PEG density required for designing stealth PEG-g-PLA NPs suitable for drug delivery applications might vary from 4 to 7%. (C) 2011 Elsevier B.V. All rights reserved.