Completely dispersible PEGylated gold nanoparticles under physiological conditions: Modification of gold nanoparticles with precisely controlled PEG-b-polyamine
Completely dispersible PEGylated gold nanoparticles under physiological conditions: Modification of gold nanoparticles with precisely controlled PEG-b-polyamine
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DOI：
10.1021/la703813f
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发表时间：
2008-05-06
期刊：
影响因子：
3.9
通讯作者：
Nagasaki, Yukio
中科院分区：
文献类型：
--
作者：
Miyamoto, Daisuke;Oishi, Motoi;Nagasaki, Yukio
采用原子转移自由基聚合(ATRP)方法合成了一种分子量可控、分子量分布窄的新型水溶性生物相容性聚合物--聚乙二醇聚(2-N，N-二甲氨基)甲基丙烯酸乙酯(PEGb-PAMA)。在合适的聚合条件下，成功地合成了具有较短PAMA链长的聚乙二醇b-PAMA。在不同的聚乙二醇化条件下制备的聚乙二醇b-PAMA对金纳米粒子(GNPs)进行修饰。在碱性条件下(pH和GT；10)，在[N]/[GNP]大于3300的条件下，PEGylated GNPs(PEGylated GNPs)表现出完全的分散稳定性，避免了凝聚。在pH 10以上，嵌段共聚物PAMA链段上的氨基完全去质子化，这意味着聚乙二醇b-PAMA与GNP表面的相互作用是通过PAMA的叔胺基多点配位实现的，而不是静电作用。通过电势和动态光散射(DLS)研究了PAMA链段氨基数目对GNP表面修饰的影响。当在过量的聚合物溶液中制备PEGGNPs时，无论PAMA链长如何，都可以观察到几乎相同的直径。经过离心法纯化后，所有的聚乙二醇GNPs的电位几乎都被屏蔽到0 mV，这表明无论链长如何，聚乙二醇b-PAMA都能有效地修饰GNP表面。但是，PAMA链长对纯化后的聚乙二醇GNPs的粒径和粒径分布有很大影响。PAMA链段较长的PEG-GNPs在纯化后发生凝聚，而PAMA链段较短的PEG-GNPs则提高了分散稳定性。热重分析的实验结果证实，随着AMA基团的减少，GNP表面的聚乙二醇单分子密度增加，分散稳定性明显依赖于聚乙二醇单分子在GNP表面的密度。具有较短AMA单元的PEGb-PAMA修饰的GNP在不同的pH条件下表现出良好的分散稳定性。得到的聚乙二醇GNP在牛血清白蛋白(BSA)溶液和95%人血清中具有良好的分散稳定性。
A novel water-soluble, biocompatible polymer, poly(ethylene glycol)-block-poly((2-N,N-dimethylamino)ethyl methacrylate) (PEG-b-PAMA), possessing controlled molecular weight with a narrow molecular weight distribution, was synthesized by the atom-transfer radical polymerization (ATRP) method. PEG-b-PAMA having a short PAMA chain length was successfully synthesized under suitable polymerization conditions. Gold nanoparticles (GNPs) were modified using PEG-b-PAMA prepared under a variety of PEGylation conditions. Under alkaline conditions (pH > 10) and an [N]/[GNP] ratio of more than 3300, the PEGylated GNPs (PEG-GNPs) showed complete dispersion stability, avoiding coagulation. The amino groups of the PAMA segment of the block copolymers were completely deprotonated above pH 10. This means that PEG-b-PAMA interacted with the GNP surface via multipoint coordination of the tertiary amino groups of PAMA, not electrostatically. The effect of the number of amino groups in the PAMA segment on GNP surface modifications was investigated by potential and dynamic light scattering (DLS) measurements. When the PEG-GNPs were prepared in excess polymer solution, almost the same diameter was observed regardless of the PAMA chain length. After the PEG-GNPs were purified by centrifugation, the potentials of all PEG-GNPs were shielded to almost 0 mV, indicating the effective modifications of the GNP surface by PEG-b-PAMA regardless of the chain length. However, the particle size and particle size distribution of the purified PEG-GNPs were strongly affected by the PAMA chain length. PEG-GNPs with longer PAMA segments underwent coagulation after purification, whereas PEG-GNPs with shorter PAMA segments increased their dispersion stability. The experimental results of the thermal gravimetric analysis confirmed that the PEG density on the GNP surface increased as the AMA units decreased to 3. Thus, the dispersion stability depended significantly on the PEG density on the GNP surface. GNPs modified with PEG-b-PAMA having short AMA units showed excellent dispersion stability under a variety of pH conditions. The excellent dispersion stability of the obtained PEG-GNP was also confirmed both in bovine serum albumin (BSA) solution and 95% human serum.