Kubiak Tomasz
Zakład Fizyki Medycznej, Uniwersytet Adama Mickiewicza w Poznaniu, Poznań, Polska.
Polim Med. 2014 Apr-Jun;44(2):119-27.
Biomedical applications of nanoparticles require that these structures are characterized by broadly defined biocompatibility. The best way to achieve this goal is to use an appropriate polymer coating, which can modify the surface properties of the nanoparticles core. The shells are formed from biodegradable material, so that the products of their decomposition can be easily eliminated from the body. Coating of nanoparticles allows to increase their stability (both in aqueous solutions and in the bloodstream), prevents agglomeration, provides the hydrophilicity of the surface and allows to attach various molecules such as drugs and tumor targeting ligands in cancer therapy. The polymer coating significantly affects the reduction of toxicity of nanoparticles and their interactions with different cell types. Chitosan and poly(ethylene glycol) (PEG) are frequently used for coating of nanostructures due to the availability and favourable properties. A major advantage of PEG is its ability to prolong the circulation time of nanoparticles injected into the bloodstream by preventing their opsonization and reducing the uptake by macrophages. Chitosan, because of its positive charge, strongly interacts with cell membranes and mucosal surfaces, which can be useful in drug delivery systems. However, it should be remembered that the molar mass and the degree of deacetylation of the used chitosan significantly affect its characteristics. The use of combined shells made of poly(ethylene glycol) and chitosan or coatings formed from new PEG based copolymers aims at further optimization of the properties of nanoparticle carriers to increase their safety and reliability in biomedical applications.
纳米颗粒的生物医学应用要求这些结构具有广义定义的生物相容性。实现这一目标的最佳方法是使用合适的聚合物涂层，它可以改变纳米颗粒核心的表面性质。外壳由可生物降解材料形成，这样其分解产物可以很容易地从体内清除。纳米颗粒的涂层可以提高其稳定性（在水溶液和血液中），防止团聚，提供表面亲水性，并允许在癌症治疗中附着各种分子，如药物和肿瘤靶向配体。聚合物涂层显著影响纳米颗粒毒性的降低及其与不同细胞类型的相互作用。由于其可得性和良好性能，壳聚糖和聚乙二醇（PEG）经常用于纳米结构的涂层。PEG的一个主要优点是它能够通过防止纳米颗粒的调理作用和减少巨噬细胞的摄取来延长注入血液中的纳米颗粒的循环时间。壳聚糖由于其正电荷，与细胞膜和粘膜表面强烈相互作用，这在药物递送系统中可能是有用的。然而，应该记住，所用壳聚糖的摩尔质量和脱乙酰度显著影响其特性。使用由聚乙二醇和壳聚糖制成的复合外壳或由新型基于PEG的共聚物形成的涂层旨在进一步优化纳米颗粒载体的性能，以提高其在生物医学应用中的安全性和可靠性。
