The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China; Bioinspired Engineering & Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, PR China.
The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China; Bioinspired Engineering & Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, PR China; Department of Mechanical Engineering & Materials Science, Washington University in St. Louis, St. Louis 63130, MO, USA; NSF Science and Technology Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis 63130, MO, USA.
J Mech Behav Biomed Mater. 2018 Dec;88:160-169. doi: 10.1016/j.jmbbm.2018.08.013. Epub 2018 Aug 24.
Biocompatible hydrogels with defined mechanical properties are critical to tissue engineering and regenerative medicine. Thiol-acrylate photopolymerized hydrogels have attracted special interest for their degradability and cytocompatibility, and for their tunable mechanical properties through controlling factors that affect reaction kinetics (e.g., photopolymerization, stoichiometry, temperature, and solvent choice). In this study, we hypothesized that the mechanical property of these hydrogels can be tuned by photoinitiators via photobleaching and by thiol-Michael addition reactions. To test this hypothesis, a multiscale mathematical model incorporating both photobleaching and thiol-Michael addition reactions was developed and validated. After validating the model, the effects of thiol concentration, light intensity, and pH values on hydrogel mechanics were investigated. Results revealed that hydrogel stiffness (i) was maximized at a light intensity-specific optimal concentration of thiol groups; (ii) increased with decreasing pH when synthesis occurred at low light intensity; and (iii) increased with decreasing light intensity when synthesis occurred at fixed precursor composition. The multiscale model revealed that the latter was due to higher initiation efficiency at lower light intensity. More broadly, the model provides a framework for predicting mechanical properties of hydrogels based upon the controllable kinetics of thiol-acrylate photopolymerization.
具有明确机械性能的生物相容性水凝胶对于组织工程和再生医学至关重要。由于其可降解性和细胞相容性，以及通过控制影响反应动力学的因素（例如光聚合、化学计量比、温度和溶剂选择）来调节机械性能，巯基-丙烯酰基光聚合水凝胶引起了特别的关注。在这项研究中，我们假设这些水凝胶的机械性能可以通过光引发剂的光漂白和巯基-Michael 加成反应来调节。为了验证这一假设，开发并验证了一个包含光漂白和巯基-Michael 加成反应的多尺度数学模型。在验证模型后，研究了巯基浓度、光强度和 pH 值对水凝胶力学性能的影响。结果表明，水凝胶的硬度（i）在特定的光强度下巯基浓度最佳时达到最大值；（ii）在低光强度下随着 pH 值的降低而增加；（iii）在固定前体组成下随着光强度的降低而增加。多尺度模型表明，后者是由于在较低的光强度下引发效率更高。更广泛地说，该模型为根据巯基-丙烯酰基光聚合的可控动力学来预测水凝胶的机械性能提供了一个框架。
