Temperature-Dependent Nanoparticle Dynamics in Poly( N -isopropylacrylamide) Gels
Temperature-Dependent Nanoparticle Dynamics in Poly( N -isopropylacrylamide) Gels
复制标题
聚（N-异丙基丙烯酰胺）凝胶中温度依赖性纳米颗粒动力学
DOI：
10.1021/acs.macromol.8b00335
复制
发表时间：
2018
期刊：
影响因子：
5.5
通讯作者：
Composto, Russell J.
中科院分区：
文献类型：
--
作者：
Parrish, Emmabeth;Seeger, Sarah C.;Composto, Russell J.
用纳米粒子(NP)探针通过单粒子示踪(SPT)表征了温度响应性水凝胶N-异丙基丙烯酰胺(NIPAAM)的局部结构。通过调节聚合物和交联剂的浓度，溶胀比和凝胶网络的限制是不同的。根据溶胀比，确定了纳米粒子的体积相变(VPTT)在32℃附近。NIPAAM链与接枝到NP上的聚乙二醇刷之间存在吸引人的相互作用，导致了约100 nm的主要定位区域。当聚合物和交联剂的浓度降低，或温度接近VPT时，NPs会逃离一次定域区，并探索更大的二次定位区(150-300 nm)，这归因于凝胶网络的限制。然而，当温度升高到VPT以上时，由于NIPAAM链的坍塌而导致的限制增加占主导地位，导致尽管温度更高，NPs仍局域化到单个区域。这项对NP动力学的研究为控制药物在响应性水凝胶系统中的释放和加载提供了洞察力。
Nanoparticle (NP) probes were used to characterize the local structure ofN-isopropylacrylamide (NIPAAM), a thermoresponsive hydrogel, using single particle tracking (SPT). Swelling ratio, and thus gel network confinement, was varied by tuning polymer and cross-linker concentrations. Based on the swelling ratio, the volume phase transition (VPTT) was determined to be near 32 °C. In general, NPs were found to be localized by two barriers. A primary localization region of approximately 100 nm was attributed to attractive interactions between the NIPAAM strands and the poly(ethylene glycol) (PEG) brush grafted to the NP. As the polymer and cross-linker concentrations were reduced, or temperature approached the VPT, NPs escape the primary localization region and explore a larger secondary localization region (150–300 nm), ascribed to confinement by the gel network. As temperature was raised above the VPT, however, the increase in confinement due to the collapse of the NIPAAM strands dominated, causing NPs to become localized to a single region despite the higher temperature. This study of NP dynamics provides insight into controlling the release and loading of drugs in responsive hydrogel systems.