Department of Chemistry, University of Oslo, Blindern, P.O. Box 1033, Blindern, N-0315 Oslo, Norway.
Department of Physics, Institute for Energy Technology, P. O. Box 40, N-2027 Kjeller, Norway.
J Colloid Interface Sci. 2018 Aug 15;524:245-255. doi: 10.1016/j.jcis.2018.04.024. Epub 2018 Apr 6.
In biomedical applications, PEGylation is frequently utilized to enhance the nanoparticles (NPs) capability for long systemic circulation times in the blood and it is also crucial to stabilize the NPs and thereby minimize their ability to agglomerate. In this study, we have synthesized poly(N-isopropylacrylamide) (PNIPAAM) nanogels with covalently attached PEG chains of different length and PEG coating densities. It is observed that in the absence of PEG coating the nanogels aggregate at elevated temperatures. It is found from dynamic light scattering (DLS) that both increased PEG length and enhanced PEG coating density have crucial influence on the stability of the nanogels. The results show that long PEG chains have a stronger impact on the shielding ability of the PEG layer on the nanogels than a high coating density of short chains. The small angle neutron scattering (SANS) measurements on PEG-coated nanogels indicate that the coated layer contract at higher temperatures but still the particles are stabilized. The bare PNIPAAM nanogels can be electrostatically stabilized by adding a small amount of an ionic surfactant.
在生物医学应用中，聚乙二醇（PEG）化常用于提高纳米颗粒（NPs）在血液中的长循环时间的能力，稳定 NPs 并最小化其聚集能力也很关键。在这项研究中，我们合成了具有不同长度和 PEG 涂层密度的共价接枝 PEG 链的聚（N-异丙基丙烯酰胺）（PNIPAAM）纳米凝胶。观察到在没有 PEG 涂层的情况下，纳米凝胶在高温下聚集。动态光散射（DLS）表明，PEG 长度的增加和 PEG 涂层密度的提高对纳米凝胶的稳定性都有至关重要的影响。结果表明，长 PEG 链对纳米凝胶 PEG 层的屏蔽能力的影响比短链的高涂层密度要强。PEG 涂层纳米凝胶的小角中子散射（SANS）测量表明，涂层在较高温度下收缩，但颗粒仍稳定。少量离子表面活性剂的添加可以使裸露的 PNIPAAM 纳米凝胶静电稳定。
