关于其对骨缺损的结构和机械适应性,3D打印(3DP)Ti6Al4V支架目前广泛应用于骨科,目的是恢复受损骨骼的功能和机械稳定性。在脚手架制造中,表面改性被认为是增强3DPTi6Al4V支架与骨之间界面相互作用的可靠策略。尽管它在骨-Ti6Al4V粘合改进方面具有优势,表面改性缺乏如预期的有效诱导骨向内生长的能力。为了克服这一挑战,在目前的工作中,3DPTi6Al4V支架的内部空隙被明胶/壳聚糖多孔基质占据,旨在充当引导骨骼向内生长的平台。首先,使用京尼平作为交联剂通过冷冻干燥制备明胶/壳聚糖基质,导致骨小梁状互连多孔网络,其特征是明胶/壳聚糖比率依赖的溶胀能力,降解和模型抗菌药物释放行为。除此之外,基质中的明胶被证明可以加速模拟体液中的生物矿化。其次,将配制的明胶/壳聚糖基质嵌入3DPTi6Al4V支架中以产生能够诱导骨向内生长的复合支架。研究表明,明胶/壳聚糖基质能使支架具有良好的生物缓释性能,随着对支架的抗压强度的最小变化。体内实验结果表明,植入4周后,与3DPTi6Al4V支架相比,在复合支架的内部结构中见证了更多的新骨形成,随着平均骨体积分数(BV/TV)值从24.09%增加到46.08%,平均骨小梁厚度(Tb。Th)值从0.118mm增加到0.278mm。因此,已证实3DPTi6Al4V支架中的内部基质在引导骨生长中起着至关重要的作用。
Regarding its structural and mechanical adaptability to bone defects, 3D printed (3DP) Ti6Al4V scaffolds are widely used in orthopedics now, purposed to restore the function and mechanical stability of impaired bone. In scaffold fabrication, surface modification is acknowledged as a reliable strategy to enhance the interface interaction between 3DP Ti6Al4V scaffold and bone. Despite its advantage in bone-Ti6Al4V bonding improvement, surface modification lacks the ability to induce bone in-growth efficiently as expected. As an attempt to overcome this challenge, in the current work the inner voids of 3DP Ti6Al4V scaffold were occupied by a
gelatin/chitosan porous matrix, purposed to act as a platform for guiding bone ingrowth. Firstly, the
gelatin/chitosan matrix was prepared via freeze-drying using genipin as a crosslinker, resulting in a trabecular bone-like interconnected porous network characterized with a
gelatin/chitosan ratio dependent swelling capability, degradation and model anti-bacterial drug release behavior. Besides of that,
gelatin in the matrix was witnessed to accelerate biomineralization in simulated body fluid. Secondly, a formulated
gelatin/chitosan matrix was embedded into 3DP Ti6Al4V scaffold to generate a composite scaffold capable of inducing bone in-growth. The followed studies showed gelatin/chitosan matrix can endow the scaffold with good biological and sustained drug release properties, along with minimal change to the compressive strength of the scaffold. The in vivo experiment results revealed that after 4 weeks of implantation, more new bone formation was witnessed in the inner structure of the composite scaffold than the 3DP Ti6Al4V scaffold, with the average bone volume fraction (BV/TV) value increased from 24.09 % to 46.08 %, the average trabecular bone thickness (Tb. Th) value increased from 0.118 mm to 0.278 mm. Therefore, it was confirmed an inner matrix in 3DP Ti6Al4V scaffold played an essential role in guiding bone in-growth.