Gong Tian-Yu, Hsu Shan-Hui, Chang Shu-Wei, Chou Chia-Ching
Institute of Polymer Science and Engineering, National Taiwan University, Roosevelt Road No. 1, Sec. 4, 10617 Taipei, Taiwan.
Department of Civil Engineering, College of Engineering, National Taiwan University, Roosevelt Road No. 1, Sec. 4, 10617 Taipei, Taiwan.
ACS Biomater Sci Eng. 2023 Nov 13;9(11):6146-6155. doi: 10.1021/acsbiomaterials.3c00948. Epub 2023 Oct 19.
Click chemistry is commonly used to prepare hydrogels, and chitosan-phenol prepared by using a Schiff base has been widely employed in the field of biomaterials. Chitosan-phenol is a derivative of chitosan; the phenol groups can disrupt both the inter- and intramolecular hydrogen bonds in chitosan, thereby reducing its crystallinity and improving its water solubility. In addition, chitosan-phenol exhibits various beneficial physiological functions. However, it is still unclear whether the degree of phenol substitution in the chitosan main chain affects the molecular interactions and structural properties of the self-healing hydrogels. To explore this issue, we investigated the molecular structure and network of self-healing hydrogels composed of chitosan-phenol with varying degrees of phenol substitution and dibenzaldehyde poly(ethylene oxide) (DB-PEO) using molecular dynamics simulations. We observed that when the degree of phenol substitution in the self-healing hydrogel was less than 15%, an increase in the degree of phenol substitution led to an increase in the interactions between chitosan-phenol and DB-PEO, and it enhanced the dynamic covalent bond cross-linking generated through the Schiff base reaction. However, when the degree of phenol substitution exceeded 15%, excessive phenol groups caused excessive intramolecular interactions within chitosan-phenol molecules, which reduced the binding between chitosan-phenol and DB-PEO. Our results revealed the influence of the degree of phenol substitution on the molecular structure of the self-healing hydrogels and showed an optimal degree of phenol substitution. These findings provide important insights for the future design of self-healing hydrogels based on chitosan and should help in enhancing the applicability of hydrogels in the field of biomedicine.
点击化学常用于制备水凝胶，通过席夫碱制备的壳聚糖 - 苯酚已在生物材料领域广泛应用。壳聚糖 - 苯酚是壳聚糖的衍生物；酚基可破坏壳聚糖分子间和分子内的氢键，从而降低其结晶度并提高其水溶性。此外，壳聚糖 - 苯酚具有多种有益的生理功能。然而，壳聚糖主链中酚取代度是否会影响自愈合水凝胶的分子相互作用和结构性质仍不清楚。为探究此问题，我们使用分子动力学模拟研究了由不同酚取代度的壳聚糖 - 苯酚和二苯甲醛聚环氧乙烷（DB - PEO）组成的自愈合水凝胶的分子结构和网络。我们观察到，当自愈合水凝胶中酚取代度小于15%时，酚取代度的增加会导致壳聚糖 - 苯酚与DB - PEO之间的相互作用增加，并增强通过席夫碱反应产生的动态共价键交联。然而，当酚取代度超过15%时，过量的酚基会导致壳聚糖 - 苯酚分子内过度的分子间相互作用，从而降低壳聚糖 - 苯酚与DB - PEO之间的结合。我们的结果揭示了酚取代度对自愈合水凝胶分子结构的影响，并显示了最佳酚取代度。这些发现为基于壳聚糖的自愈合水凝胶的未来设计提供了重要见解，并应有助于提高水凝胶在生物医学领域的适用性。
