Moghimi S M
Molecular Targeting and Polymer Toxicology Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton BN2 4GJ, UK.
Biochim Biophys Acta. 2002 Jun 12;1590(1-3):131-9. doi: 10.1016/s0167-4889(02)00204-5.
A two-step approach is described to chemically camouflage the inert surface of model polystyrene nanospheres of 60 nm in diameter against recognition by the body's defenses. The first step was based on the strong protein adsorbing potency of polystyrene, and the second step utilized the chemical reactivity of the adsorbed proteins for conjugation with cyanuric chloride-activated methoxypoly(ethyleneglycol)5000, mPEG5000. Bovine serum albumin (BSA) and rat IgG were used as models of non-immune and immune proteins, respectively. The maximum adsorbance values for both proteins were near expectation for a close-packed monolayer. Adsorption isotherms studies and analysis of the hydrodynamic thickness of the adsorbed protein layer confirmed the close-packed side-on mode of adsorption for BSA and the end-on mode of adsorption for IgG, respectively. Nucleophiles on the adsorbed proteins were then reacted with cyanuric chloride activated mPEG5000. The average poly(ethyleneglycol) (PEG) content for a 60-nm nanospheres was found to be 13.7+/-0.4 micromol PEG/micromol BSA and 3.6+/-0.3 micromol PEG/micromol IgG. The interaction of both PEG-bearing nanospheres with the hydrophobic column material octyl-agarose indicated surface heterogeneity among the nanospheres. Only nanospheres with the most hydrophilic phenotype (approximately 70% of the total population) exhibited stealth properties after intravenous injection to rats. In contrast to the described approach, incubation of uncoated nanospheres with preformed BSA-mPEG5000 conjugates failed to produce long circulating entities. For design of splenotropic particles cyanuric chloride-activated mPEG5000 was conjugated to BSA-coated polystyrene beads of 225 nm in diameter. Despite their stealth property to hepatic Kupffer cell recognition, these nanospheres were cleared by the splenic red pulp macrophages.
本文描述了一种两步法，用于对直径为60 nm的聚苯乙烯纳米球模型的惰性表面进行化学伪装，以防止被机体防御系统识别。第一步基于聚苯乙烯强大的蛋白质吸附能力，第二步利用吸附蛋白质与三聚氯氰活化的甲氧基聚乙二醇5000（mPEG5000）共轭的化学反应性。牛血清白蛋白（BSA）和大鼠IgG分别用作非免疫蛋白和免疫蛋白的模型。两种蛋白质的最大吸附值接近紧密堆积单层的预期值。吸附等温线研究和吸附蛋白质层流体动力学厚度分析分别证实了BSA的紧密堆积侧向吸附模式和IgG的端向吸附模式。然后，使吸附蛋白质上的亲核试剂与三聚氯氰活化的mPEG5000反应。发现60 nm纳米球的平均聚乙二醇（PEG）含量为13.7±0.4 μmol PEG/μmol BSA和3.6±0.3 μmol PEG/μmol IgG。两种负载PEG的纳米球与疏水柱材料辛基琼脂糖的相互作用表明纳米球之间存在表面异质性。静脉注射给大鼠后，只有具有最亲水表型的纳米球（约占总数的70%）表现出隐形特性。与所述方法相反，将未包被的纳米球与预先形成的BSA-mPEG5000共轭物孵育未能产生长循环实体。为了设计脾靶向颗粒，将三聚氯氰活化的mPEG5000与直径为225 nm的BSA包被的聚苯乙烯珠共轭。尽管这些纳米球对肝库普弗细胞识别具有隐形特性，但它们被脾红髓巨噬细胞清除。
