Synthesis of PEG and Quaternary Ammonium Grafted Silicone Copolymers as Nanoemulsifiers
Synthesis of PEG and Quaternary Ammonium Grafted Silicone Copolymers as Nanoemulsifiers
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DOI：
10.1021/acsapm.0c00103
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发表时间：
2020-05-01
影响因子：
5
通讯作者：
Green, Matthew D.
中科院分区：
文献类型：
--
作者：
Gupta, Srishti;Singh, Pummy;Green, Matthew D.
两亲性有机硅共聚物是一类令人兴奋的生物医学相关聚合物，可用于基于磁共振成像（MRI）的细胞标记和血氧测定研究。然而，溶液的特性和形成稳定纳米乳的能力必须首先被证明。因此，采用一锅反应途径，将具有3个（PEG(3)）或11个（PEG(11)）重复单元的烯丙基聚乙二醇（PEG）或烯丙基三乙基溴化铵（QUAT）取代基以3种不同PEG：铵的摩尔比接枝到聚氢甲基硅氧烷骨架上，成功地合成了一系列两亲性硅氧烷。通过改变PEG长度和PEG:QUAT摩尔比来调节聚合物的亲水性和表面张力，并通过1H NMR和FT-IR光谱对聚合物结构进行了表征。结果表明，随着PEG和QUAT基团的加入，水接触角增大，而表面张力对PEG(3)浓度最为敏感。有机硅接枝共聚物的临界胶束浓度随聚乙二醇含量的增加而降低。动态光散射（DLS）和低温透射电子显微镜研究了溶液的结构和形成包封聚二甲基硅氧烷（PDMS）油的纳米乳液的能力。DLS显示含PEG(3)的接枝共聚物的尺寸一致，但随着QUAT浓度的增加，PEG（11）样品的尺寸分布发生了变化。最后，接枝共聚物成功地形成了含有PDMS的稳定纳米乳液，其粒径适合于基于mri的细胞标记和氧饱和度测定应用。
Amphiphilic silicone copolymers are an exciting class of biomedically relevant polymers that can be used for magnetic resonance imaging (MRI)-based cell labeling and oximetry studies. However, the solution characteristics and the ability to form stable nanoemulsions must be first demonstrated. Therefore, a series of amphiphilic siloxanes were successfully synthesized by grafting allylic poly(ethylene glycol) (PEG) with three (PEG(3)) or 11 (PEG(11)) repeat units or allylic triethylammonium bromide (QUAT) substituents onto polyhydromethylsiloxane backbones at three different PEG:ammonium molar ratios by using a one-pot reaction pathway. The PEG length and the PEG:QUAT molar ratio were varied to tune the hydrophilicity and surface tension, and the polymer structures were confirmed by using 1H NMR and FT-IR spectroscopy. The results show that the water contact angle increased upon attaching the PEG and QUAT groups, while the surface tension was most sensitive to the PEG(3) concentration. Also, the critical micelle concentration of the silicone graft copolymers decreased with an increase in the PEG content. Dynamic light scattering (DLS) and cryogenic transmission electron microscopy probed the solution structures and the ability to form nanoemulsions encapsulating polydimethylsiloxane (PDMS) oils. The graft copolymers containing PEG(3) showed consistent sizes by DLS, but the size distribution changed for the PEG(11) samples as the QUAT concentration increased. Finally, the graft copolymers successfully formed stable nanoemulsions containing PDMS with particle sizes that are appropriate for MRI-based cell labeling and oximetry applications.