Hou Yaping, Fei Ruochong, Burkes Jonathan C, Lee Shin Duk, Munoz-Pinto Dany, Hahn Mariah S, Grunlan Melissa A
Department of Biomedical Engineering, Materials Science and Engineering Program, Texas A&M University, College Station, 77843 TX, USA.
Department of Chemical Engineering, Texas A&M University, College Station, 77843 TX, USA.
J Biomater Tissue Eng. 2011 Jun 1;1(1). doi: 10.1166/jbt.2011.1005.
Thermal modulation reversibly switches poly(-isopropylacrylamide) (PNIPAAm) hydrogels between a water-swollen and a deswollen state which is useful for a variety of biomedical applications. The utility and efficiency of PNIPAAm hydrogels requires tailoring their rate of deswelling/reswelling, mechanical properties and/or optical clarity. In the current work, we prepared novel thermoresponsive nanocomposite hydrogels comprised of a PNIPAAm hydrogel matrix and polysiloxane colloidal nanoparticles (54 nm ave. diameter) via photopolymerization of aqueous solutions of NIPAAm monomer, ,'-methylenebisacrylamide (BIS, crosslinker), photoinitiator and 0.5-4.0 wt% polysiloxane nanoparticles (wt% solids of nanoparticles with respect to NIPAAm weight) at ~7 °C. At these nanoparticle concentrations, the nanocomposite hydrogels were more optically transparent versus those prepared with analogous larger nanoparticles (219 nm ave. diameter). The volume phase transition temperature (VPTT) of the nanocomposite hydrogels was conveniently unaltered versus that of the pure PNIPAAm hydrogel. Incorporation of nanoparticles caused enhancement in modulus as well as the extent and rate of deswelling. When cooled from 37 °C to 25 °C, mouse smooth muscle precursor cells (10T1/2) were effectively detached from nanocomposite hydrogel surfaces due to hydrogel swelling.
热调制可使聚（N-异丙基丙烯酰胺）（PNIPAAm）水凝胶在水溶胀和去溶胀状态之间可逆切换，这对多种生物医学应用很有用。PNIPAAm水凝胶的实用性和效率需要调整其去溶胀/再溶胀速率、机械性能和/或光学透明度。在当前工作中，我们通过在约7°C下光聚合NIPAAm单体、N,N'-亚甲基双丙烯酰胺（BIS，交联剂）、光引发剂和0.5-4.0 wt%聚硅氧烷纳米颗粒（纳米颗粒固体重量相对于NIPAAm重量的wt%）的水溶液，制备了由PNIPAAm水凝胶基质和聚硅氧烷胶体纳米颗粒（平均直径约54 nm）组成的新型热响应纳米复合水凝胶。在这些纳米颗粒浓度下，与用类似的较大纳米颗粒（平均直径约219 nm）制备的纳米复合水凝胶相比，纳米复合水凝胶具有更高的光学透明度。纳米复合水凝胶的体积相变温度（VPTT）与纯PNIPAAm水凝胶的相比方便地未改变。纳米颗粒的掺入导致模量以及去溶胀程度和速率的增强。当从37°C冷却到25°C时，由于水凝胶溶胀，小鼠平滑肌前体细胞（10T1/2）有效地从纳米复合水凝胶表面脱离。
