Highly flexible and degradable dual setting systems based on PEG-hydrogels and brushite cement.
Highly flexible and degradable dual setting systems based on PEG-hydrogels and brushite cement.
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DOI：
10.1016/j.actbio.2018.08.028
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发表时间：
2018-10
影响因子：
9.7
通讯作者：
Michaela Rödel;J. Teßmar;J. Groll;U. Gbureck
中科院分区：
文献类型：
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作者：
Michaela Rödel;J. Teßmar;J. Groll;U. Gbureck
对于天然骨的组成，我们建立了一个可降解的双固化系统的不同聚（乙二醇）（PEG）为基础的水凝胶结合透钙磷石水泥。这个想法是用有机聚合物相来增强无机磷酸钙矿物相，以改变水泥的延展性和弹性。通过这种双固化方法制备了非常柔韧的样品，其中含有高分子量PEG基水凝胶前体的样品具有完全可逆的弹性。使用脱钙剂EDTA，整个无机相溶解，由于Ca 2+络合和尺寸稳定的水凝胶，得到的复合材料内的均匀的聚合物相。这也通过SEM分析证实，其中没有观察到相的不连续性或附聚。另外的XRD测量证明了相干聚合物基质对从β-TCP/MCPA到透钙磷石的转化的显著影响，其中信号强度降低。结果证实了固化反应和凝胶化的连续运行过程，而不抑制透钙磷石的转化和水凝胶和水泥的互穿网络的形成。这种新开发的双固化系统的优势是基于材料的可降解性以及灵活性，这可能是一个有前途的工具，用于非承重颅颌面缺损的骨再生应用。然而，纯无机材料表现出脆性断裂行为。在这里，添加聚合物相可以影响机械性能，以产生更具延展性和柔性的材料。理想情况下，该聚合物相应在骨水泥凝固期间通过聚合反应形成，以实现高聚合物负载而不改变骨水泥粘度，并且其应与骨水泥本身类似地在体内可降解。因此，我们开发了一种基于透钙磷石和丙交酯改性的聚（乙二醇）二甲基丙烯酸酯（PEG-PLLA-DMA）基水凝胶的同时水泥固化的双固化系统。很明显，在自由基聚合后，凝胶在水泥内形成连续相，大大降低了水泥的脆性。
With respect to the composition of natural bone, we established a degradable dual setting system of different poly(ethylene glycol) (PEG)-based hydrogels combined with a brushite cement. The idea was to reinforce the inorganic calcium phosphate mineral phase with an organic, polymeric phase to alter the cement’s properties towards ductility and elasticity. Extremely flexible samples were producedviathis dual setting approach with a fully reversible elasticity of the samples containing high molecular weight PEG-based hydrogel precursors. Using the decalcifying agent EDTA, the whole inorganic phase was dissolved due to Ca2+-complexation and dimensionally stable hydrogels were obtained, indicating a homogenous polymeric phase within the composites. This was also confirmed by SEM-analysis, where no discontinuities or agglomerations of the phase were observed. Additional XRD-measurements proved a significant influence of the coherent polymeric matrix on the conversion from β-TCP/MCPA to brushite with a decrease in signal intensity. The results confirmed a parallelly running process of setting reaction and gelation without an inhibition of the conversion to brushite and the formation of interpenetrating networks of hydrogel and cement. The strengths of this newly developed dual setting system are based on the material degradability as well as flexibility, which can be a promising tool for bone regeneration applications in non-load bearing craniomaxillofacial defects.Statement of SignificanceBrushite based calcium phosphate cements (CPCs) are known as bone replacement materials, which degradein vivoand are replaced by native bone. However, the pure inorganic material shows a brittle fracture behavior. Here, the addition of a polymeric phase can influence the mechanical properties to create more ductile and flexible materials. This polymeric phase should ideally form during cement setting by a polymerization reaction to achieve high polymer loads without altering cement viscosity and it should be degradablein vivosimilar to the cement itself. Therefore, we developed a dual setting system based on simultaneous cement setting of brushite and lactide modified poly(ethylene glycol) dimethacrylate (PEG-PLLA-DMA)-based hydrogel. It was evident that the gels form a continuous phase within the cement after radical polymerization with a strong reduction of cement brittleness.