Tissue Engineering and Microfluidics Laboratory, Australian Institute for Bioengineering and Nanotechnology, ‡Centre for Microscopy and Microanalysis, §School of Chemistry and Molecular Biosciences, and ∥The School of Chemical Engineering, The University of Queensland , St. Lucia, 4072 Australia.
Biomacromolecules. 2013 Oct 14;14(10):3780-92. doi: 10.1021/bm401168h. Epub 2013 Sep 19.
The results of a systematic investigation into the gelation behavior of α-cyclodextrin (α-CD) and Pluronic (poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers) pseudopolyrotaxane (PPR) hydrogels are reported here in terms of the effects of temperature, α-CD concentration, and Pluronic type (Pluronic F68 and Pluronic F127). It was found that α-CD significantly modifies the gelation behavior of Pluronic solutions and that the PPR hydrogels are highly sensitive to changes in the α-CD concentration. In some cases, the addition of α-CD was found to be detrimental to the gelation process, leading to slower gelation kinetics and weaker gels than with Pluronic alone. However, in other cases, the hydrogels formed in the presence of the α-CDs reached higher moduli and showed faster gelation kinetics than with Pluronic alone and in some instances α-CD allowed the formation of hydrogels from Pluronic solutions that would normally not undergo gelation. Depending on composition and ratio of α-CD/Pluronic, these highly viscoelastic hydrogels displayed elastic shear modulus values ranging from 2 kPa to 7 MPa, gelation times ranging from a few seconds to a few hours and self-healing behaviors post failure. Using dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS), we probed the resident structure of these systems, and from these insights we have proposed a new molecular mechanism that accounts for the macroscopic properties observed.
本文报道了 α-环糊精（α-CD）与泊洛沙姆（聚环氧乙烷-聚环氧丙烷-聚环氧乙烷嵌段共聚物）伪聚轮烷（PPR）水凝胶的胶凝行为的系统研究结果，主要考察了温度、α-CD 浓度和泊洛沙姆类型（Pluronic F68 和 Pluronic F127）的影响。结果表明，α-CD 显著改变了泊洛沙姆溶液的胶凝行为，而且 PPR 水凝胶对 α-CD 浓度的变化非常敏感。在某些情况下，添加 α-CD 会对胶凝过程产生不利影响，导致胶凝动力学减慢，形成的凝胶强度比单独使用泊洛沙姆时弱。然而，在其他情况下，在 α-CD 的存在下形成的水凝胶达到了更高的模量，并表现出比单独使用泊洛沙姆更快的胶凝动力学，在某些情况下，α-CD 允许原本不能胶凝的泊洛沙姆溶液形成水凝胶。根据 α-CD/泊洛沙姆的组成和比例，这些高粘弹性水凝胶的弹性剪切模量值范围从 2 kPa 到 7 MPa，胶凝时间从几秒钟到几个小时不等，并且在失效后具有自修复行为。我们通过动态光散射（DLS）和小角 X 射线散射（SAXS）探测了这些体系的固有结构，并从这些研究结果中提出了一个新的分子机制来解释观察到的宏观性质。
