Enhanced mechanical properties of photo-clickable thiol-ene PEG hydrogels through repeated photopolymerization of in-swollen macromer.
Enhanced mechanical properties of photo-clickable thiol-ene PEG hydrogels through repeated photopolymerization of in-swollen macromer.
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DOI：
10.1039/c6sm01768a
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发表时间：
2016-11-09
期刊：
影响因子：
3.4
通讯作者：
McLeod RR
中科院分区：
文献类型：
--
作者：
Fiedler CI;Aisenbrey EA;Wahlquist JA;Heveran CM;Ferguson VL;Bryant SJ;McLeod RR
目前用于组织工程的水凝胶仅限于复制的组织构建体内的单一范围的机械性能。我们表明，通过单一水凝胶前体溶液到现有的聚合水凝胶中的重复溶胀，然后曝光，增加了水凝胶的机械性能。该过程是证明与光点击的硫醇-烯水凝胶使用生物相容性的前体溶液的聚（乙二醇）二硫醇和8臂聚（乙二醇）官能化与异丙基苯。前体溶液中的聚合物分数以5重量%、10重量%和20重量%变化，并且使用非化学计量比的硫醇：烯，留下可用于后续反应的游离烯。对相同的前体溶液进行多次溶胀和暴露循环。压缩模量增加了三到十倍（配方依赖性），而体积溶胀比降低了两倍，与交联密度增加一致。改性的水凝胶还通过在比初始水凝胶大五倍的压缩力下断裂而显示出增加的韧性。我们将韧性的增加归因于溶胀大分子聚合物的重复光聚合所产生的交联密度的随后增加。该技术证明了通过利用可应用于传统三维打印系统以空间控制局部机械性能的溶胀和聚合过程来显著改变水凝胶网络性能的能力。使用单一的前体溶液，增强的PEG水凝胶的机械性能证明了利用扩散，溶胀，和光聚合。
Current hydrogels used for tissue engineering are limited to a single range of mechanical properites within the replicated tissue construct. We show that repeated in-swelling by a single hydrogel pre-cursor solution into an existing polymerized hydrogel followed by photo-exposure increases hydrogel mechanical properties. The process is demonstrated with a photo-clickable thiol-ene hydrogel using a biocompatible precursor solution of poly(ethylene glycol) dithiol and 8-arm poly(ethylene glycol) functionalized with norbornene. The polymer fraction in the precursor solution was varied by 5, 10, and 20 percent by weight and an off-stoichiometric ratio of thiol:ene was used, leaving free enes available for subsequent reaction. Multiple swelling and exposure cycles for the same precursor solution were performed. The compressive modulus increased by a factor between three and ten (formulation dependent), while volume swelling ratio decreased by a factor of two, consistent with increased crosslink density. The modified hydrogels also demonstrate increased toughness by fracturing at compressive forces five times greater than the initial hydrogel. We attribute the increased toughness to subsequent increases in crosslink density created by the repeated photopolymerization of in-swollen macromer. This technique demonstrates the ability to significantly modify hydrogel network properites by exploiting swelling and polymerization processes that can be applied to traditional three-dimensional printing systems to spatially control local mechanical properties. Using a single precursor solution, enhanced mechanical properties of PEG hydrogels are demonstrated by harnessing diffusion, swelling, and photopolymerization.