Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan.
Biomaterials. 2011 Jul;32(21):4959-67. doi: 10.1016/j.biomaterials.2011.03.049. Epub 2011 Apr 11.
Physicochemical properties, such as particle size, shape, molecular weight, surface charge and composition, play a key role in the cellular uptake of polymeric nanoparticles. Antigen-encapsulated biodegradable nanoparticles have considerable potential for use in vaccine delivery systems. Although it is accepted that particle size is important for the induction of antigen-specific immune responses in vivo, little is known about how their size affects their intracellular fate. Here, we demonstrate that the size effects on the cellular uptake, intracellular degradation and distribution of protein-encapsulated nanoparticles. We prepared size-regulated ovalbumin (OVA)-encapsulated nanoparticles composed of hydrophobically modified poly(γ-glutamic acid) (γ-PGA). These nanoparticles were efficiently taken up by macrophages, and also delivered encapsulated OVA from the endosomes to the cytoplasm. Comparing 40-200 nm-sized nanoparticles, there was no significant difference in their intracellular distribution. Interestingly, the size of the nanoparticles affected the intracellular degradation of the encapsulated OVA. The uptake of OVA alone by macrophages resulted in early degradation of the OVA. In contrast, the degradation of OVA encapsulated into the nanoparticles was attenuated as compared to free OVA. A difference in OVA degradation kinetics was observed between the particle sizes, the degradation of small nanoparticles was slower than for the larger ones. These results indicate that particle size is an important factor for the intracellular degradation of encapsulated proteins and nanoparticles. These results will provide a rational design of nanoparticle-based vaccines to control immune responses.
物理化学性质，如粒径、形状、分子量、表面电荷和组成，在聚合物纳米粒子的细胞摄取中起着关键作用。包封抗原的可生物降解纳米粒子在疫苗传递系统中有很大的应用潜力。尽管人们普遍认为粒径对于体内诱导抗原特异性免疫反应很重要，但对于其大小如何影响其细胞内命运知之甚少。在这里，我们证明了粒径对蛋白包封纳米粒子的细胞摄取、细胞内降解和分布的影响。我们制备了由疏水性修饰的聚（γ-谷氨酸）（γ-PGA）组成的大小可调节的卵清蛋白（OVA）包封纳米粒子。这些纳米粒子被巨噬细胞有效摄取，并将包封的 OVA 从内体运送到细胞质。比较 40-200nm 大小的纳米粒子，它们在细胞内的分布没有显著差异。有趣的是，纳米粒子的大小影响了包封的 OVA 的细胞内降解。巨噬细胞单独摄取 OVA 会导致 OVA 的早期降解。相比之下，与游离 OVA 相比，包封在纳米粒子中的 OVA 的降解受到抑制。在粒径之间观察到 OVA 降解动力学的差异，小纳米粒子的降解速度比大纳米粒子慢。这些结果表明粒径是影响包封蛋白和纳米粒子细胞内降解的重要因素。这些结果将为控制免疫反应的基于纳米粒子的疫苗的合理设计提供依据。
