模拟体液浸泡法评价柠檬酸钙的生物学特性

背景：柠檬酸钙本身的溶解性能优于磷酸钙、硫酸钙等其他钙生物材料,并且合成的柠檬酸钙致密性良好,在降解过程中可高效平稳释放钙离子,所以更适合用于骨折缺损的填充,为骨折愈合初期提供所需要的钙离子。 目的：将天然生物矿化牡蛎壳和柠檬酸反应生成生物型柠檬酸钙生物材料,以期望在骨折愈合修复方面得到良好的应用。 方法：通过球磨机粉碎天然生物矿化的牡蛎壳,再经研磨制备成适合粒径的牡蛎壳粉,与柠檬酸反应得到生物型柠檬酸钙,再经研磨,过筛,得到适宜大小的柠檬酸钙颗粒。应用X射线和FT-IR光谱研究材料的结构和组分,扫描电子显微镜观察材料的表面形态,模拟体液实验评价其生物特性。 结果与结论：牡蛎壳粉末与饱和柠檬酸发生化学反应,转化生成了柠檬酸钙材料,并且晶体结构排列有序,形态紧密,晶体之间结合紧凑,具有一定的力学性能,这种结构也有利于延长材料的降解时间,平稳释放钙离子。柠檬酸钙在降解吸收过程中并未明显改变体液的pH值,整个pH值波动于7.20-7.46之间,对人体细胞的刺激性小。随着柠檬酸钙材料的逐渐降解,溶液中Ca2+浓度逐渐增大,且释放相对平缓,最终达到适宜成骨细胞增殖分化所需的胞外钙浓度,逐步稳定在7 mmol/L左右。表明以天然牡蛎壳为原料制备的柠檬酸钙具有优良的生物特性,作为人工骨材料具有天然的优越性。

Simulated body fluid immersion method for assessing biological characteristics of calcium citrate

BACKGROUND: Calcium citrate has a better solubility than calcium phosphate, calcium sulfate, and other calcium biomaterials. The synthetic calcium citrate has a good denseness, and stably releases calcium ions at a high efficiency during the degradation. Consequently, it may be more suitable for the filling of fracture defects, providing needed calcium ions for early fracture healing. OBJECTIVE: To prepare calcium citrate biomaterials with a novel formulation based on the natural bio-mineralized oyster shells and citric acid so as to expect to get a good application in fracture healing repair. METHODS:Crushing, grinding, and chemical reaction methods were used for refinement. Particle size analyzer, X-ray diffraction, scanning electron microscope, and Fourier transform infrared spectroscopy were adopted for analysis of the size distribution, composition, mineral phases, and micro-morphology. Biological characteristics were evaluated through a simulated body fluid experiment.  RESULTS AND CONCLUSION:Oyster shell powder was reacted with saturated citric acid to produce the calcium citrate material that had uniform crystal structure and compact bonding among crystal bodies, and exhibited a certain mechanical ability. The calcium citrate material had a good crystal structure that was conductive to prolong the degradation time. The calcium citrate released calcium ions slowly, and did not produce dramatic changes in the pH value (7.20-7.46) of the surrounding in the dissolution process. With the gradual degradation of calcium citrate materials, Ca2+ concentration in solution increased gradually and stably, and ultimately achieved an appropriate concentration of   7 mmol/L, suitable for osteoblast proliferation and differentiation. Calcium citrate prepared using natural oyster shell has good biological properties, and exhibits a natural superiority to artificial bone materials.