Research Institute of Materials Science and State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, People's Republic of China.
Biomed Mater. 2012 Oct;7(5):055008. doi: 10.1088/1748-6041/7/5/055008. Epub 2012 Sep 4.
One-end-connected short poly(ethylene glycol) (PEG) side chains were facilely introduced into the poly(N-isopropylacrylamide) (PNIPAm) nanocomposite hydrogel (NC gel) via in situ copolymerization of NIPAm monomer and PEG macromonomer in the aqueous suspension of hectorite clay Laponite XLS. The NC gels were characterized with Fourier transform infrared and x-ray photoelectron spectroscopy for the composition, DSC and transmittance for the phase separation temperature, dynamic mechanical spectra and swelling ratio for the interaction. Increasing the PEG content led to a small increase in the storage modulus and the lower critical solution temperature (LCST) of the copolymerized NC gels, and the LCST of the copolymerized NC gels was still below 37 °C. The L929 cell adhesion and proliferation on the surface of these NC gels were not suppressed by the incorporation of hydrophilic PEG side chains. By lowering temperature below the LCST, the cell sheet spontaneously detached from the copolymerized NC gels. The surface morphology and surface wettability of the NC gels were detected by atom force microscope and contact angle measurement. A rough and hydrophilic surface induced by a small amount of PEG side chains was found to be favorable to accelerate the cell sheet detachment, probably due to the enhanced water permeation into the gel-cell sheet interface.
一端相连的短聚乙二醇（PEG）侧链通过 N-异丙基丙烯酰胺（NIPAm）单体和 PEG 大分子单体在水滑石 Laponite XLS 的水悬浮液中的原位共聚，被轻易地引入到聚（N-异丙基丙烯酰胺）（PNIPAm）纳米复合水凝胶（NC 凝胶）中。通过傅里叶变换红外和 X 射线光电子能谱对组成进行了表征，通过差示扫描量热法和透光率对相分离温度进行了表征，通过动态力学谱和溶胀比对相互作用进行了表征。增加 PEG 的含量会导致共聚物 NC 凝胶的储能模量和较低临界溶液温度（LCST）略有增加，并且共聚物 NC 凝胶的 LCST仍低于 37°C。L929 细胞在这些 NC 凝胶表面的黏附和增殖并没有被亲水性 PEG 侧链的掺入所抑制。通过将温度降低到 LCST 以下，细胞片会自动从共聚物 NC 凝胶上脱落。通过原子力显微镜和接触角测量检测了 NC 凝胶的表面形貌和表面润湿性。发现少量 PEG 侧链诱导的粗糙和亲水表面有利于加速细胞片的脱落，这可能是由于水更易渗透到凝胶-细胞片界面。
