3D Printing and Nanofabrication of Multifunctional Scaffold Materials for Biomedical Applications

全世界每年进行数百万次肌肉骨骼组织移植手术，以治疗创伤、退行性疾病和肿瘤切除。从患者身上获取的组织(自体)是首选的组织移植材料，尽管存在缺陷和潜在的并发症，因为工程材料一直无法满足包括生物兼容性、生物降解性、机械性能和多孔结构在内的各种多功能要求。纳米制造技术使材料系统能够由纳米级构建块的精确组合组成，包括单个分子和纳米颗粒。这些技术已被用于生产具有一系列独特特性和功能的纳米结构材料系统，包括高强度和刚性、生物兼容性、生物降解性和治疗药物的输送/释放。将纳米加工与3D打印相结合，不仅可以对结构和成分进行纳米级控制，还可以控制微米级的多孔结构，并有助于扩大纳米级工艺，以生产宏大尺寸的块状材料。聚合物-粘土纳米复合材料在多孔开孔泡沫上的纳米加工使得能够生产具有可控硬度和孔隙率的宏观纳米复合材料多孔材料，范围从柔软的弹性体泡沫到非常硬、轻的蜂窝和格子材料[1]。在表面剪裁材料成分增强了这些材料的生物相容性，可应用于工程组织支架材料[2]。需要进一步的工作来将受控的机械性能、孔隙率和生物相容性与包括生物降解性和治疗性药物输送在内的额外功能结合起来。实现这些特性和功能将有助于解决尚未满足的主要需求，即工程组织支架材料，以取代现有的治疗策略使用自体移植，这是有限的供应和有效性。纳米复合薄膜将使用水为基础的纳米制造技术。以承载功能为目标的材料系统将被机械表征，而以生物降解性为目标的材料将以体外降解为特征。结合承载功能和生物可降解功能的杂化材料系统将被设计并表征为不同组成和纳米结构的功能。多孔纳米复合材料将通过纳米加工在初始孔结构可控的3D打印支架上制备。多孔纳米复合材料的多孔结构、力学性能和降解特性将根据工程肌肉骨骼组织支架的要求进行评估。还将通过与生物医学研究人员的本地和国际合作，探索用于治疗性药物输送和增强生物相容性的材料系统的整合。

Millions of musculoskeletal tissue graft procedures are performed worldwide on an annual basis to treat traumatic injuries, degenerative diseases, and tumour resections. Tissue harvested from the patient (autogenic) are the preferred tissue grafting materials, despite drawbacks and potential complications, because engineered materials have been unable to meet the diverse range of multifunctional requirements, which includes biocompatibility, biodegradation, mechanical properties, and porous structure. Nanofabrication techniques enable material systems composed of precise combinations of nano-scale building blocks, including individual molecules and nano-particles. These techniques have been utilised to produce nano-structured material systems with a range of unique properties and functions, including high strength and stiffness, biocompatibility, biodegradability, and delivery/release of therapeutic drugs. Combining nanofabrication with 3D-printing allows control over micro-scale porous structure, in addition to nano-scale control over structure and composition, and helps scale-up nano-scale processes for the production of macro-scale bulk materials. Nanofabrication of polymer-clay nanocomposites onto porous open-cell foams has enabled the production of macro-scale nanocomposite porous materials with controlled stiffness and porosity spanning remarkable ranges from those of soft elastomer foams to very stiff, lightweight honeycomb and lattice materials [1]. Tailoring the material composition at the surface has enhanced the biocompatibility of these materials for application as engineered tissue scaffold materials [2]. Further work is needed to combine controlled mechanical properties, porosity, and biocompatibility with additional functionalization including biodegradability, and therapeutic drug-delivery. Achieving these properties and functionalities will help address the major unmet need for engineered tissue scaffold materials as replacements for existing treatment strategies using autogenous grafts, which are limited in supply and efficacy.Nanocomposite thin-films will be produced using an aqueous-based nanofabrication technique. Material systems targeting load-bearing functionality will be mechanically characterized, while materials targeting biodegradability will be characterized in terms of in vitro degradation. Hybrid material systems combining load-bearing and biodegradable functionalities will be designed and characterized as functions of varying composition and nano-structure. Porous nanocomposites will be produced via nanofabrication onto 3D-printed scaffolds with controlled initial pore structure. The porous structure, mechanical properties, and degradation characteristics of porous nanocomposites will be assessed against requirements for engineered musculoskeletal tissue scaffolds. The integration of material systems for therapeutic drug-delivery and enhanced biocompatibility will also be explored via local and international collaborations with biomedical researchers.