Physical Materials Science and Composite Materials Centre , National Research Tomsk Polytechnic University , 634050 Tomsk , Russia.
Department of Biotechnology , Ghent University , 9000 Ghent , Belgium.
ACS Appl Mater Interfaces. 2019 May 29;11(21):19522-19533. doi: 10.1021/acsami.9b04936. Epub 2019 May 17.
Elaboration of novel biocomposites providing simultaneously both biodegradability and stimulated bone tissue repair is essential for regenerative medicine. In particular, piezoelectric biocomposites are attractive because of a possibility to electrically stimulate cell response. In the present study, novel CaCO-mineralized piezoelectric biodegradable scaffolds based on two polymers, poly[( R)3-hydroxybutyrate] (PHB) and poly[3-hydroxybutyrate- co-3-hydroxyvalerate] (PHBV), are presented. Mineralization of the scaffold surface is carried out by the in situ synthesis of CaCO in the vaterite and calcite polymorphs using ultrasound (U/S). Comparative characterization of PHB and PHBV scaffolds demonstrated an impact of the porosity and surface charge on the mineralization in a dynamic mechanical system, as no essential distinction was observed in wettability, structure, and surface chemical compositions. A significantly higher (4.3 times) piezoelectric charge and a higher porosity (∼15%) lead to a more homogenous CaCO growth in 3-D fibrous structures and result in a two times higher relative mass increase for PHB scaffolds compared to that for PHBV. This also increases the local ion concentration incurred upon mineralization under U/S-generated dynamic mechanical conditions. The modification of the wettability for PHB and PHBV scaffolds from hydrophobic (nonmineralized fibers) to superhydrophilic (mineralized fibers) led to a pronounced apatite-forming behavior of scaffolds in a simulated body fluid. In turn, this results in the formation of a dense monolayer of well-distributed and proliferated osteoblast cells along the fibers. CaCO-mineralized PHBV surfaces had a higher osteoblast cell adhesion and proliferation assigned to a higher amount of CaCO on the surface compared to that on PHB scaffolds, as incurred from micro-computed tomography (μCT). Importantly, a cell viability study confirmed biocompatibility of all the scaffolds. Thus, hybrid biocomposites based on the piezoelectric PHB polymers represent an effective scaffold platform functionalized by an inorganic phase and stimulating the growth of the bone tissue.
为了再生医学的发展，研制能够同时提供生物降解性和刺激骨组织修复的新型生物复合材料至关重要。特别是，由于可以电刺激细胞反应，压电生物复合材料具有吸引力。在本研究中，提出了基于两种聚合物，聚[(R)-3-羟基丁酸酯]（PHB）和聚[3-羟基丁酸酯-共-3-羟基戊酸酯]（PHBV）的新型 CaCO3 矿化压电可生物降解支架。使用超声（U/S）原位合成文石和方解石多晶型的 CaCO3 对支架表面进行矿化。对 PHB 和 PHBV 支架的比较研究表明，在动态力学系统中，孔隙率和表面电荷对矿化的影响，因为在润湿性、结构和表面化学成分方面没有明显的区别。较高的（4.3 倍）压电电荷和较高的孔隙率（约 15%）导致 3-D 纤维结构中 CaCO3 生长更均匀，并使 PHB 支架的相对质量增加了两倍，而 PHBV 支架则增加了两倍。这也增加了在 U/S 产生的动态力学条件下矿化时的局部离子浓度。对 PHB 和 PHBV 支架的润湿性进行改性，从疏水性（未矿化纤维）变为超亲水性（矿化纤维），导致支架在模拟体液中表现出明显的磷灰石形成行为。反过来，这导致沿纤维形成一层致密的、分布均匀的和增殖的成骨细胞单层。与 PHB 支架相比，CaCO3 矿化 PHBV 表面的成骨细胞黏附率和增殖率更高，这归因于表面的 CaCO3 量较高，这一点可以从微计算机断层扫描（μCT）看出。重要的是，细胞活力研究证实了所有支架的生物相容性。因此，基于压电 PHB 聚合物的混合生物复合材料代表了一种有效的支架平台，通过无机相进行功能化并刺激骨组织的生长。
