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

全世界每年进行数百万例肌肉骨骼组织移植手术，以治疗创伤性损伤、退行性疾病和肿瘤切除。尽管存在缺陷和潜在的并发症，但从患者身上采集的组织（自体）是首选的组织移植材料，因为工程材料无法满足多种多功能要求，包括生物相容性、生物降解、机械性能和多孔结构。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，包括高强度和刚度、生物相容性、生物可降解性和治疗药物的输送/释放。将纳米制造与3d打印相结合，除了对结构和成分进行纳米级控制外，还可以控制微观尺度的多孔结构，并有助于扩大纳米尺度工艺，以生产宏观尺度的大块材料。聚合物-粘土纳米复合材料在多孔开孔泡沫上的纳米加工，使宏观尺度的纳米复合多孔材料的生产成为可能，其刚度和孔隙度的控制范围从柔软的弹性体泡沫到非常坚硬、轻质的蜂窝和晶格材料[1]。裁剪表面的材料组成增强了这些材料作为工程组织支架材料的生物相容性。进一步的工作需要将控制的机械性能、孔隙度和生物相容性与其他功能化（包括生物降解性和治疗性药物传递）结合起来。实现这些特性和功能将有助于解决工程组织支架材料的主要未满足需求，以替代现有的使用自体移植物的治疗策略，这些治疗策略在供应和疗效上都受到限制。纳米复合薄膜将采用水基纳米加工技术生产。以承载功能为目标的材料系统将被机械表征，而以生物可降解性为目标的材料将被体外降解表征。结合承重和生物降解功能的杂化材料系统将被设计和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技术在具有可控初始孔隙结构的3d打印支架上制备。多孔纳米复合材料的多孔结构、机械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。通过与生物医学研究人员的本地和国际合作，还将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集成。

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.