RMS Foundation, Bischmattstrasse 12, CH-2544 Bettlach, Switzerland.
RMS Foundation, Bischmattstrasse 12, CH-2544 Bettlach, Switzerland.
Acta Biomater. 2020 Jan 15;102:440-457. doi: 10.1016/j.actbio.2019.11.035. Epub 2019 Nov 20.
Several mechanisms proposed to explain the osteoinductive potential of calcium phosphates involve surface mineralization ("bioactivity") and mention the occurrence of concentration gradients between the inner and the outer part of the implanted material. Determining the evolution of the local chemical environment occurring inside the pores of an implanted bone graft substitute (BGS) is therefore highly relevant. A quantitative and fast method was developed to measure the chemical changes occurring within the pores of β-Tricalcium Phosphate (β-TCP) granules incubated in a simulated body fluid. A factorial design of experiment was used to test the effect of particle size, specific surface area, microporosity, and purity of the β-TCP granules. Large pH, calcium and phosphate concentration changes were observed inside the BGS and lasted for several days. The kinetics and magnitude of these changes (up to 2 pH units) largely depended on the processing and properties of the granules. Interestingly, processing parameters that increased the kinetics and magnitude of the local chemical changes are parameters considered to favor calcium phosphate osteoinduction, suggesting that the model might be useful to predict the osteoinductive potential of BGSs. STATEMENT OF SIGNIFICANCE: Recent results suggest that in situ mineralization of biomaterials (polymers, ceramics, metals) might be key in their ability to trigger ectopic bone formation. This is the reason why the effect on in situ mineralization of various synthesis parameters of β-tricalcium phosphate granules was studied (size, microporosity, specific surface area, and Ca/P molar ratio). To the best of our knowledge, this is the first article devoted to the chemical changes occurring within the pores of a bone graft substitute. We believe that the manuscript will prove to be highly important in the design and mechanistic understanding of drug-free osteoinductive biomaterials.
几种解释磷酸钙类材料具有成骨性潜力的机制涉及表面矿化（“生物活性”），并提到了植入材料内部和外部之间浓度梯度的出现。因此，确定植入骨移植物替代物（BGS）孔隙内局部化学环境的演变非常重要。开发了一种定量和快速的方法来测量在模拟体液中孵育的β-磷酸三钙（β-TCP）颗粒的孔隙内发生的化学变化。实验设计因素用于测试β-TCP 颗粒的粒径、比表面积、微孔率和纯度对这些变化的影响。在 BGS 内观察到大的 pH 值、钙和磷酸盐浓度变化，并持续了数天。这些变化的动力学和幅度（高达 2 pH 单位）在很大程度上取决于颗粒的加工和性质。有趣的是，增加局部化学变化的动力学和幅度的加工参数是被认为有利于磷酸钙成骨性的参数，这表明该模型可能有助于预测 BGS 的成骨性潜力。意义声明：最近的结果表明，生物材料（聚合物、陶瓷、金属）的原位矿化可能是其引发异位骨形成能力的关键。这就是为什么研究了β-磷酸三钙颗粒的各种合成参数（粒径、微孔率、比表面积和 Ca/P 摩尔比）对原位矿化的影响。据我们所知，这是第一篇专门研究骨移植物替代物孔隙内发生的化学变化的文章。我们相信，这篇论文将在无药物成骨性生物材料的设计和机制理解方面证明是非常重要的。
