Department of Nutritional Sciences, University of Connecticut, Storrs, CT, 06269, United States.
College of Life Science, Yangtze University, Jingzhou, Hubei, 434025, PR China.
Colloids Surf B Biointerfaces. 2021 Sep;205:111829. doi: 10.1016/j.colsurfb.2021.111829. Epub 2021 May 21.
Phytoglycogen (PG), a water-soluble glycogen-like α-d-glucan, exists as natural dendritic nanoparticles which are known as a promising solubility enhancer and delivery vehicle for lipophilic compounds. However, the practical applications of PG in food and pharmaceutical fields are limited by their high hydrophilicity and relatively low encapsulation efficiency compared with other delivery systems. The objectives of this work were to chemically modify native PG nanoparticles with hydrophobic groups and to characterize their physicochemical properties, as well as to evaluate the application feasibility of modified PG (mPG) nanoparticles as a carrier for hydrophobic bioactive compounds. The surface hydroxyl groups of PG nanoparticles were capped with various anhydrides, e.g., acetic, valeric, and N-caprylic, to obtain the PG nanoparticles with different hydrophobicity. Successful modification by acyl groups was evidenced by both Fourier-transform infrared and nuclear magnetic resonance spectroscopies. The mPG nanoparticles exhibited a more compact structure and homogeneous size distribution as revealed by dynamic light scattering measurement and visualized by transmission electron microscope, while their size slightly increased with the chain length of anhydride. Rheological measurement revealed that the viscosity of mPG at low shear rate was increased with the increase of degree of substitution due to the intermolecular hydrophobic association. A novel pH-driven method to load curcumin showed significantly higher encapsulation efficiency and greater antioxidant activity compared with traditional ethanol mediated loading method. Hydrophobic modification of natural dendritic PG nanostructures demonstrates promising potential to develop food-grade nanocarriers for lipophilic bioactive compounds with improved bioactivity.
植物糖原 (PG) 是一种水溶性的糖原样α-d-葡聚糖，以天然树枝状纳米颗粒的形式存在，作为亲脂性化合物的增溶剂和递送载体具有很大的应用潜力。然而，与其他递送系统相比，PG 由于其较高的亲水性和相对较低的包封效率，其在食品和制药领域的实际应用受到限制。本研究的目的是通过化学修饰天然 PG 纳米颗粒，引入疏水性基团，对其理化性质进行表征，并评估修饰 PG(mPG)纳米颗粒作为疏水生物活性化合物载体的应用可行性。通过各种酸酐，如乙酸酐、正戊酸酐和辛酸酐，对 PG 纳米颗粒表面的羟基进行封端，得到不同疏水性的 PG 纳米颗粒。傅里叶变换红外光谱和核磁共振波谱证明了酰基的成功修饰。动态光散射测量和透射电子显微镜观察表明，mPG 纳米颗粒具有更紧凑的结构和更均匀的粒径分布，而其粒径随着酸酐链长的增加而略有增大。流变学测量表明，由于分子间的疏水缔合，mPG 在低剪切速率下的粘度随取代度的增加而增加。与传统的乙醇介导的加载方法相比，一种新的 pH 驱动的姜黄素加载方法显示出更高的包封效率和更大的抗氧化活性。天然树枝状 PG 纳米结构的疏水性修饰为开发具有改善生物活性的亲脂性生物活性化合物的食品级纳米载体展示了广阔的应用前景。
