Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan 81746-73441, Islamic Republic of Iran.
Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan 81746-73441, Islamic Republic of Iran.
Mater Sci Eng C Mater Biol Appl. 2021 Jan;120:111750. doi: 10.1016/j.msec.2020.111750. Epub 2020 Nov 27.
Fabrication of simultaneously robust and superabsorbent gelatin-based hydrogels for biomedical applications still remains a challenge due to lack of locally dissipative points in the presence of large water content. Here, we apply a synthesis strategy through which water absorbency and energy dissipative points are separated, and toughening mechanism is active closely at the crack tip. For this, gelatin-based microgels (GeMs) were synthesized in a way that concentrated supramolecular interactions were present to increase the energy necessary to propagate a macroscopic crack. The microgels were interlocked to each other via both temporary hydrophobic associations and permanent covalent crosslinks, in which the sacrificial binds sustained the toughness due to the mobility of the junction zones and particles sliding. However, chemical crosslinking points preserved the integrity and fast recoverability of the hydrogel. Hysteresis increased strongly with increasing supramolecular interactions within the network. The prepared hydrogels showed energy loss and swelling ratio up to 3440 J. m and 830%, respectively, which was not achievable with conventional network fabrication methods. The microgels were also assessed for their in vivo biocompatibility in a rat subcutaneous pocket assay. Results of hematoxylin and eosin (H&E) staining demonstrated regeneration of the tissue around the scaffolds without incorporation of growth factors. Also, vascularization within the scaffolds was observed after 4 weeks implantation. These results indicate that our strategy is a promising method to manipulate those valuable polymers, which lose their toughness and applicability with increasing their water content.
由于缺乏大量水分存在时的局部耗散点，用于生物医学应用的同时具有强韧性和超吸水性的明胶基水凝胶的制备仍然是一个挑战。在这里，我们应用了一种通过该策略将吸水性和能量耗散点分离的合成策略，并且在裂纹尖端使增韧机理紧密发挥作用。为此，通过存在浓缩的超分子相互作用来合成基于明胶的微凝胶 (GeMs)，以增加传播宏观裂纹所需的能量。微凝胶通过临时疏水性缔合和永久性共价交联相互锁定，其中牺牲键由于连接区和颗粒滑动的可移动性而保持韧性。然而，化学交联点保持了水凝胶的完整性和快速恢复能力。网络内的超分子相互作用越强，滞后性就越强。所制备的水凝胶的能量损耗和溶胀比分别高达 3440 J·m 和 830%，这是传统网络制造方法无法实现的。还在大鼠皮下口袋实验中评估了微凝胶的体内生物相容性。苏木精和曙红 (H&E) 染色的结果表明，在没有加入生长因子的情况下，支架周围的组织得到了再生。另外，在植入 4 周后观察到支架内的血管化。这些结果表明，我们的策略是一种有前途的方法，可以控制那些随着含水量的增加而失去韧性和适用性的有价值的聚合物。
