Sopcak Tibor, Medvecky Lubomir, Giretova Maria, Stulajterova Radoslava, Durisin Juraj
Division of Functional and Hybrid Systems, Institute of Materials Research of the Slovak Academy of Sciences, Kosice, Slovakia.
J Biomater Appl. 2018 Feb;32(7):871-885. doi: 10.1177/0885328217747126. Epub 2017 Dec 9.
Bone cements based on magnesium phosphates such as newberyite (N; MgHPO.3HO) have been shown as potential bone substitutes due to their biocompatibility, biodegradability and ability to support osteoblast differentiation and proliferation. Newberyite can hydrolyze to hydrated magnesium phosphate compounds (e.g. bobierite (Mg(PO).8HO)) at alkaline conditions. In this study, 25 and 50 wt% of crystalline β -wollastonite (woll; CaSiO) was admixed to newberyite powder in order to both enhance the acid-base hydrolysis of newberyite and to produce a functional bone cement. The setting process of wollastonite/newberyite cement mixtures started with the hydrolysis of the wollastonite with further transformation of newberyite into bobierite and the formation of magnesium silicate phase. The results demonstrated that 25 wollastonite/newberyite and 50 wollastonite/newberyite cement pastes at optimal powder/liquid ratios had final setting times of ∼34 and 25 min and compressive strength values of 18 and 32 MPa after seven days setting, respectively. The tests of cytotoxicity of cement extracts on osteoblastic cells and contact cytotoxicity of the cement substrates showed different results. The osteoblasts cultured in cement extracts readily proliferated which confirmed the non-cytotoxic concentration of ions released from both cements. On the other hand, a strong cytotoxic character of 25 wollastonite/newberyite sample surface in contrary to high (∼80%) proliferation activity of cells on the 50 wollastonite/newberyite cement substrate was observed. The differences in cell proliferation activity was attributed to different surface topographies of cement substrates, where needle-like precipitated microcrystals of magnesium phosphate phase (in 25 wollastonite/newberyite cement) prevented the adhesion and proliferation of osteoblasts contrary to the smoother surface covered by extremely fine nanoparticles in the 50 wollastonite/newberyite cement.
基于磷酸镁的骨水泥，如新硅钙石（N；MgHPO₄·3H₂O），因其生物相容性、生物可降解性以及支持成骨细胞分化和增殖的能力，已被证明是潜在的骨替代物。新硅钙石在碱性条件下可水解为水合磷酸镁化合物（如磷镁石（Mg₃(PO₄)₂·8H₂O））。在本研究中，将25wt%和50wt%的结晶β - 硅灰石（硅灰石；CaSiO₃）与新硅钙石粉末混合，以增强新硅钙石的酸碱水解作用，并制备一种功能性骨水泥。硅灰石/新硅钙石水泥混合物的凝结过程始于硅灰石的水解，随后新硅钙石进一步转化为磷镁石，并形成硅酸镁相。结果表明，在最佳粉液比下，25%硅灰石/新硅钙石和50%硅灰石/新硅钙石水泥浆体的终凝时间分别约为34分钟和25分钟，养护7天后的抗压强度值分别为18MPa和32MPa。水泥提取物对成骨细胞的细胞毒性测试以及水泥基质的接触细胞毒性测试结果不同。在水泥提取物中培养的成骨细胞易于增殖，这证实了两种水泥释放的离子浓度无细胞毒性。另一方面，观察到25%硅灰石/新硅钙石样品表面具有很强的细胞毒性，而50%硅灰石/新硅钙石水泥基质上的细胞增殖活性很高（约80%）。细胞增殖活性的差异归因于水泥基质不同的表面形貌，其中磷酸镁相的针状沉淀微晶（在25%硅灰石/新硅钙石水泥中）阻碍了成骨细胞的黏附和增殖，而50%硅灰石/新硅钙石水泥中覆盖着极细纳米颗粒的表面更光滑。
