Mahamoud Moustapha Mohamed, Ketema Tadesse Mekonnin, Kuwahara Yutaka, Takafuji Makoto
Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto City 860-8555, Japan.
International Research Organization for Advanced Science and Technology (IROAST), Kumamoto University, Kumamoto City 860-8555, Japan.
Gels. 2024 Aug 12;10(8):527. doi: 10.3390/gels10080527.
Hydrogels composed of natural and synthetic polymers have considerable potential for use in diverse areas such as biomedical applications and water purification. This is primarily because of their biocompatibility, biodegradability, and low toxicity. The widespread usage of composite hydrogels is hindered by a lack of simultaneous properties, such as high strength and low swelling rate. Herein, we report the preparation of novel hydrogels composed of polyvinyl alcohol (PVA)-intercalated agar polymer networks physically crosslinked with tannic acid. The hydrogel was subjected to multiple freeze/thaw (F/T) cycles (1, 3, and 5), and it was found to exhibit the highest strength after 5 F/T cycles. After 1 F/T cycle, the tensile strength of the composite hydrogel reached 1.56 MPa with a 1.0 wt% crosslinker, whereas after 5 F/T cycles, it increased to 3.77 MPa with a reduced amount (0.75 wt%) of the crosslinker. In addition, the swelling ability decreased upon increasing the crosslinker content and number of F/T cycles. Furthermore, the hydrogel demonstrated excellent water retention and a strong ability to adhere to different substrates. We have successfully implemented an innovative approach to improve the mechanical properties of PVA-based hydrogels by combining the use of tannic acid as a cross-linking agent and multiple F/T cycles. The developed hydrogels are expected to facilitate new developments in hydrogel technology, thus impacting diverse fields such as biomedical (wound dressing and artificial cartilage).
由天然和合成聚合物组成的水凝胶在生物医学应用和水净化等不同领域具有相当大的应用潜力。这主要是由于它们的生物相容性、生物降解性和低毒性。复合水凝胶的广泛应用受到缺乏诸如高强度和低溶胀率等同时具备的性能的阻碍。在此，我们报道了由聚乙烯醇（PVA）插层琼脂聚合物网络与单宁酸物理交联而成的新型水凝胶的制备。对该水凝胶进行多次冻融（F/T）循环（1次、3次和5次），发现其在5次F/T循环后表现出最高强度。在1次F/T循环后，复合水凝胶在交联剂含量为1.0 wt%时的拉伸强度达到1.56 MPa，而在5次F/T循环后，交联剂用量减少（0.75 wt%），拉伸强度增加到3.77 MPa。此外，随着交联剂含量和F/T循环次数的增加，溶胀能力降低。此外，该水凝胶表现出优异的保水性和对不同基材的强粘附能力。我们通过结合使用单宁酸作为交联剂和多次F/T循环，成功实施了一种创新方法来改善基于PVA的水凝胶的机械性能。预计所开发的水凝胶将推动水凝胶技术的新发展，从而影响生物医学（伤口敷料和人工软骨）等不同领域。
