聚乳酸(PLA)已被广泛用作材料挤出增材制造(AM)的长丝,以开发骨组织工程中的患者特异性支架。羟基磷灰石(HA),天然骨骼的主要组成部分,已被广泛认为是骨传导生物分子。这里,受贻贝粘附现象的启发,在这项研究中,聚多巴胺(PDA)涂层应用于3D打印PLA支架(PLA@PDA)的表面,作为固定HA纳米颗粒(nHA)的通用粘合剂平台。进行了综合分析,以了解用nHA和PDA功能化的3D打印PLA支架的理化性质,以作为骨再生替代品进行有效的临床应用。扫描电子显微镜(SEM)和元素色散X射线(EDX)证实,在3天和7天的涂层(PLA@PDA-HA3和PLA@PDA-HA7)后,在PLA@PDA的表面上成功加载了nHA颗粒。而表面微观形貌和孔隙率保持不变的表面改性。热重分析(TGA)表明,在PLA支架表面负载了质量比为7.7%和12.3%的nHA,分别。润湿性测试表明,nHA涂层支架的亲水性大大提高,而机械性能保持不变。三维激光扫描共聚焦显微镜(3DLS)图像显示,表面粗糙度显着增加,在PLA@PDA-HA7中达到0.402μm的Sa(算术平均高度)。28天的体外降解结果表明,将nHA引入到PLA表面增强了其降解性能,如SEM图像和重量损失测试所证明的。此外,记录了PLA@PDA-HA3和PLA@PDA-HA7的Ca2可持续释放,在降解过程中。相比之下,nHA释放的羟基倾向于中和局部酸性环境,更有利于成骨细胞分化和细胞外矿化。一起来看,这种容易的表面改性提供了3D打印PLA支架具有有效的骨再生特性,通过沉积Ca2+含量,改善表面亲水性,提高体外降解率。
Polylactic acid (PLA) has been widely used as filaments for material extrusion additive manufacturing (AM) to develop patient-specific scaffolds in bone tissue engineering. Hydroxyapatite (HA), a major component of natural bone, has been extensively recognized as an osteoconductive biomolecule. Here, inspired by the mussel-adhesive phenomenon, in this study, polydopamine (PDA) coating was applied to the surface of 3D printed PLA scaffolds (PLA@PDA), acting as a versatile adhesive platform for immobilizing HA nanoparticles (nHA). Comprehensive analyses were performed to understand the physicochemical properties of the 3D-printed PLA scaffold functionalized with nHA and PDA for their potent clinical application as a bone regenerative substitute. Scanning electron microscopy (SEM) and element dispersive X-ray (EDX) confirmed a successful loading of nHA particles on the surface of PLA@PDA after 3 and 7 days of coating (PLA@PDA-HA3 and PLA@PDA-HA7), while the surface micromorphology and porosity remain unchanged after surface modification. The thermogravimetric analysis (TGA) showed that 7.7 % and 12.3% mass ratio of nHA were loaded on the PLA scaffold surface, respectively. The wettability test indicated that the hydrophilicity of nHA-coated scaffolds was greatly enhanced, while the mechanical properties remained uncompromised. The 3D laser scanning confocal microscope (3DLS) images revealed that the surface roughness was significantly increased, reaching Sa (arithmetic mean height) of 0.402 μm in PLA@PDA-HA7. Twenty-eight days of in-vitro degradation results showed that the introduction of nHA to the PLA surface enhances its degradation properties, as evidenced by the SEM images and weight loss test. Furthermore, a sustainable release of Ca2+ from PLA@PDA-HA3 and PLA@PDA-HA7 was recorded, during the degradation process. In contrast, the released hydroxyl group of nHA tends to neutralize the local acidic environments, which was more conducive to osteoblastic differentiation and extracellular mineralization. Taken together, this facile surface modification provides 3D printed PLA scaffolds with effective bone regenerative properties by depositing Ca2+ contents, improving surface hydrophilicity, and enhancing the in-vitro degradation rate.