Department of Biomedical Engineering, University of Texas at Austin, Austin, Texas 78712, USA.
ACS Nano. 2012 Oct 23;6(10):9182-90. doi: 10.1021/nn3035155. Epub 2012 Sep 25.
Polyethylene glycol (PEG) surface coatings are widely used to render stealth properties to nanoparticles in biological applications. There is abundant literature on the benefits of PEG coatings and their ability to reduce protein adsorption, to diminish nonspecific interactions with cells, and to improve pharmacokinetics, but very little discussion of the limitations of PEG coatings. Here, we show that physiological concentrations of cysteine and cystine can displace methoxy-PEG-thiol molecules from the gold nanoparticle (GNP) surface that leads to protein adsorption and cell uptake in macrophages within 24 h. Furthermore, we address this problem by incorporating an alkyl linker between the PEG and the thiol moieties that provides a hydrophobic shield layer between the gold surface and the hydrophilic outer PEG layer. The mPEG-alkyl-thiol coating greatly reduces protein adsorption on GNPs and their macrophage uptake. This has important implications for the design of GNP for biological systems.
聚乙二醇（PEG）表面涂层被广泛应用于赋予生物应用中纳米颗粒的隐身特性。关于 PEG 涂层的益处及其减少蛋白质吸附、减少与细胞的非特异性相互作用以及改善药代动力学的能力，已有大量文献报道，但很少有关于 PEG 涂层的局限性的讨论。在这里，我们表明，半胱氨酸和胱氨酸的生理浓度可以从金纳米颗粒（GNP）表面置换甲氧基-PEG-硫醇分子，导致在 24 小时内巨噬细胞中蛋白质吸附和细胞摄取。此外，我们通过在 PEG 和硫醇部分之间引入烷基链接来解决这个问题，在金表面和亲水的外部 PEG 层之间提供疏水屏蔽层。mPEG-烷基-硫醇涂层大大减少了 GNP 上的蛋白质吸附及其巨噬细胞摄取。这对生物系统中 GNP 的设计具有重要意义。
