We present biocompatible hydrogel systems suitable for biomineralization processes based on hyperbranched polyglycidol cross-linked with acrylamide copolymer bearing carbonyl-coordinated boronic acid. At neutral pH, diol functional groups of HbPGL react with boronic acid of polyacrylamide to generate 3D network in water by the formation of boronic ester cross-links. The dynamic associative/dissociative characteristics of the cross-links makes the network reversible. The presented hydrogels display self-healing properties and are injectable, facilitating gap filing of bone tissue. The ¹H HR MAS DOSY NMR studies reveal that acrylamide copolymer plays the role of the network framework, whereas HbPGL macromolecules, due to their compact structure, move between reactive sites of the copolymer. The influence of the copolymer macromolecules entanglements and overall polymer concentrations on macromolecules mobility and stress relaxation processes is investigated. The process of hydrogel biomineralization results from hydrolysis of 1-naphthyl phosphate calcium salt catalyzed by encapsulation in hydrogel alkaline phosphatase. The environment of the hydrogel is entirely neutral toward the enzyme. However, the activity of alkaline phosphatase encapsulated within the hydrogel structure is diffusion-limited. In this article, based on the detailed characteristics of three model hydrogel systems, we demonstrate the influence of the hydrogel permeability on the encapsulated enzyme activity and calcium phosphate formation rate. The ¹H HR MAS DOSY NMR is used to monitor diffusion low-molecular weight compound within hydrogels, whereas ³¹P HR MAS NMR facilitates monitoring of the progress of biomineralization in situ within hydrogels. The results show a direct correlation between low molecular diffusivity in hydrogels and network dynamics. We demonstrate that the morphology of in situ-generated calcium phosphate within three model HbPGL/poly(AM-ran-APBA) hydrogels of different low molecular permeability varies substantially from sparsely deployed large, well-defined crystals to an even distribution within the polymers polycrystalline continuous network.

中文翻译：

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基于可逆交联的超支化聚缩水甘油在水凝胶中原位进行扩散控制的生物矿化作用

我们提出了适合生物矿化过程的生物相容性水凝胶体系，该体系基于与支链羰基硼酸的丙烯酰胺共聚物交联的超支化聚缩水甘油。在中性pH下，HbPGL的二醇官能团与聚丙烯酰胺的硼酸反应，通过形成硼酸酯交联键在水中生成3D网络。交叉链接的动态关联/分离特性使网络具有可逆性。提出的水凝胶显示出自愈特性，并且是可注射的，有利于骨组织的间隙填充。在¹H HR MAS DOSY NMR研究表明，丙烯酰胺共聚物起网络骨架的作用，而HbPGL大分子由于结构紧凑而在共聚物的反应性位点之间移动。研究了共聚物大分子缠结和总聚合物浓度对大分子迁移率和应力松弛过程的影响。水凝胶生物矿化的过程是由封装在水凝胶碱性磷酸酶中催化的1-萘磷酸磷酸钙盐的水解产生的。水凝胶的环境对酶完全是中性的。然而，包裹在水凝胶结构内的碱性磷酸酶的活性是受扩散限制的。在本文中，基于三种模型水凝胶系统的详细特征，我们证明了水凝胶渗透性对封装的酶活性和磷酸钙形成速率的影响。这¹ H HR MAS DOSY NMR用于监测水凝胶中扩散的低分子量化合物，而³¹ P HR MAS NMR则有助于监测水凝胶中原位生物矿化的进程。结果表明，水凝胶中低分子扩散率与网络动力学之间存在直接关系。我们证明，在三种低分子渗透性不同的HbPGL / poly（AM- ran -APBA）水凝胶模型中，原位生成的磷酸钙的形态从稀疏部署的大尺寸，明确定义的晶体到聚合物多晶内的均匀分布有很大不同连续网络。