Department of Materials Science and Engineering, University of Ioannina, Ioannina, Greece.
Clinics of Cardiology, Department of Medicine, University of Ioannina, Ioannina, Greece.
J Biomed Mater Res B Appl Biomater. 2019 Feb;107(2):223-231. doi: 10.1002/jbm.b.34113. Epub 2018 Apr 24.
The spontaneous uptake of Ca -ions is a unique property of alginate hydrogels, which, along with their high biocompatibility, disintegration (approximately within 2 weeks), and morphological similarity to heart tissue, makes them attractive as scaffolding materials in therapies in infarct myocardium. To shed light on the aforementioned ability, thorough theoretical calculations were carried out with the density functional theory (DFT) method. The influence of Ca-content οn the molecular structure and the thermodynamic stability of the alginate hydrogel was determined; what is more, these results effectively interpreted the experimental findings, as well. This analysis suggests that in Ca-free or Ca-deficient alginates spontaneous Ca cations uptake can occur from the biological environment and develop, via chelation reaction, a well-formed and thermodynamically stable hydrogel in situ inside the tissue. The highest degree of cross linking results in viscosity peak. Nevertheless, further increase of Ca-content in alginate structure beyond this peak results in products with poorer thermodynamic stability. Structural optimization DFT calculations revealed that the destabilization of the Ca-rich alginate hydrogels is attributed to changes of the alginate chain molecule, which are relaxation, weakening, and eventually total collapse of the bond between the units of the alginate chain. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 223-231, 2019.
海藻酸盐水凝胶具有独特的钙离子自吸收特性，加上其具有生物相容性、可在大约 2 周内分解以及与心脏组织形态相似等优点，使其成为梗死心肌治疗中支架材料的理想选择。为了深入了解上述能力，我们采用密度泛函理论（DFT）方法进行了深入的理论计算。确定了钙离子含量对海藻酸盐水凝胶分子结构和热力学稳定性的影响；此外，这些结果还有效地解释了实验结果。该分析表明，在无钙或缺钙的海藻酸盐中，钙离子可以从生物环境中自发吸收，并通过螯合反应在组织内原位形成具有良好形态和热力学稳定性的水凝胶。交联度越高，峰值粘度越大。然而，海藻酸盐结构中钙离子含量进一步增加会导致产物热力学稳定性变差。结构优化的 DFT 计算表明，富含钙离子的海藻酸盐水凝胶的不稳定性归因于海藻酸盐链分子的变化，即海藻酸盐链单元之间的键松弛、减弱，最终完全崩溃。© 2018 年威利父子公司。J 生物医学材料研究部分 B：应用生物材料，107B：223-231，2019 年。
