Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA; Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, USA; Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD, USA.
Acta Biomater. 2024 Sep 1;185:126-143. doi: 10.1016/j.actbio.2024.07.011. Epub 2024 Jul 14.
Oxygen (O)-delivering tissue substitutes have shown tremendous potential for enhancing tissue regeneration, maturation, and healing. As O is both a metabolite and powerful signaling molecule, providing controlled delivery is crucial for optimizing its beneficial effects in the treatment of critical-sized injuries. Here, we report the design and fabrication of 3D-printed, biodegradable, O-generating bone scaffold comprising calcium peroxide (CPO) that once hydrolytically activated, provides long-term generation of oxygen at a controlled, concentration-dependent manner, and polycaprolactone (PCL), a hydrophobic polymer that regulate the interaction of CPO with water, preventing burst release of O at early time points. When anoxic conditions were simulated in vitro, CPO-PCL scaffolds maintained the survival and proliferation of human adipose-derived stem/stromal cells (hASCs) relative to PCL-only controls. We assessed the in vivo osteogenic efficacy of hASC-seeded CPO-PCL scaffolds implanted in a non-healing critical-sized 4-mm calvarial defects in nude mice for 8 weeks. Even without exogenous osteoinductive factors, CPO-PCL scaffolds demonstrated increased new bone volume compared to PCL-only scaffolds as verified by both microcomputed tomography analysis and histological assessments. Lastly, we employed a quantitative 3D lightsheet microscopy platform to determine that O-generating scaffolds had similar vascular volumes with slightly higher presence of CD31Emcn pro-osteogenic, type H vessels and increased number of Osterix skeletal progenitor cells relative to PCL-only scaffolds. In summary, 3D-printed O generating CPO-PCL scaffolds with tunable O release rates provide a facile, customizable strategy for effectively treating, craniofacial bone defects. STATEMENT OF SIGNIFICANCE: Oxygen(O)-delivering bone substitutes show promise in defect repair applications by supplying O to the cells within or around the graft, improving cell survivability and enhancing bone matrix mineralization. A novel O-generating bone scaffold has been 3D printed for the first-time which ensures patient and defect specificity. 3D printed calcium peroxide-polycaprolactone (CPO-PCL) bone scaffold provides uninterrupted O supply for 22 days allowing cell survival in deprived O and nutrient conditions. For the first time, O-driven bone regenerative environment in mice calvaria has been captured by light-sheet imaging which illuminates abundance of Osterix+ cells, angiogenesis at a single cell resolution indicating active site of bone remodeling and growth in the presence of O.
提供氧的组织替代物在促进组织再生、成熟和愈合方面显示出巨大的潜力。由于氧既是代谢物又是强大的信号分子，因此控制其释放对于优化其在治疗临界尺寸损伤中的有益效果至关重要。在这里，我们报告了一种 3D 打印的、可生物降解的、包含过氧化钙 (CPO) 的氧生成骨支架的设计和制造，一旦水解激活，CPO 就会以受控的、浓度依赖性的方式长期产生氧，而聚己内酯 (PCL) 是一种疏水性聚合物，可调节 CPO 与水的相互作用，防止氧在早期的爆发性释放。当在体外模拟缺氧条件时，CPO-PCL 支架相对于仅 PCL 对照维持了人脂肪来源的干细胞/基质细胞 (hASC) 的存活和增殖。我们评估了 hASC 接种的 CPO-PCL 支架在裸鼠非愈合临界尺寸 4mm 颅骨缺损中的体内成骨功效 8 周。即使没有外源性成骨诱导因子，CPO-PCL 支架也表现出比仅 PCL 支架更高的新骨体积，这通过微计算机断层扫描分析和组织学评估得到了证实。最后，我们采用定量 3D 光片显微镜平台确定，与仅 PCL 支架相比，产生 O 的支架具有相似的血管体积，稍高的 CD31Emcn 促成骨、H 型血管的存在和更多的 Osterix 骨骼祖细胞。总之，具有可调氧释放率的 3D 打印 O 生成 CPO-PCL 支架为有效治疗颅面骨缺损提供了一种简单、可定制的策略。
氧供骨替代物在缺陷修复应用中具有很大的应用前景，因为它可以向移植物内或周围的细胞提供 O，提高细胞存活率并增强骨基质矿化。这是首次 3D 打印新型 O 生成骨支架，确保了患者和缺陷的特异性。3D 打印的过氧化钙-聚己内酯（CPO-PCL）骨支架可在 22 天内提供不间断的 O 供应，使细胞在缺氧和营养缺乏的条件下存活。首次通过光片成像捕获了小鼠颅骨中的 O 驱动的骨再生环境，该成像以单细胞分辨率照亮了大量的 Osterix+细胞、血管生成，表明在 O 的存在下骨重塑和生长的活跃部位。
