Centre for Biomaterials in Surgical Reconstruction and Regeneration, Division of Surgery & Interventional Science, University College London, London NW3 2PF, United Kingdom.
UCL Ear Institute, Royal National Throat Nose and Ear Hospital and University College London, London, United Kingdom.
Acta Biomater. 2019 Feb;85:157-171. doi: 10.1016/j.actbio.2018.12.019. Epub 2018 Dec 14.
Increasing evidence suggests the contribution of the dynamic mechanical properties of the extracellular matrix (ECM) to regulate tissue remodeling and regeneration. Following our recent study on a family of thermoresponsive 'stiffness memory' elastomeric nanohybrid scaffolds manufactured via an indirect 3D printing guided thermally-induced phase separation process (3D-TIPS), this work reports in vitro and in vivo cellular responses towards these scaffolds with different initial stiffness and hierarchically interconnected porous structure. The viability of mouse embryonic dermal fibroblasts in vitro and the tissue responses during the stiffness softening of the scaffolds subcutaneously implanted in rats for three months were evaluated by immunohistochemistry and histology. Scaffolds with a higher initial stiffness and a hierarchical porous structure outperformed softer ones, providing initial mechanical support to cells and surrounding tissues before promoting cell and tissue growth during stiffness softening. Vascularization was guided throughout the digitally printed interconnected networks. All scaffolds exhibited polarization of the macrophage response from a macrophage phenotype type I (M1) towards a macrophage phenotype type II (M2) and down-regulation of the T-cell proliferative response with increasing implantation time; however, scaffolds with a more pronounced thermo-responsive stiffness memory mechanism exerted higher inflammo-informed effects. These results pave the way for personalized and biologically responsive soft tissue implants and implantable device with better mechanical matches, angiogenesis and tissue integration. Statement of Significance This work reports cellular responses to a family of 3D-TIPS thermoresponsive nanohybrid elastomer scaffolds with different stiffness softening both in vitro and in vivo rat models. The results, for the first time, have revealed the effects of initial stiffness and dynamic stiffness softening of the scaffolds on tissue integration, vascularization and inflammo-responses, without coupling chemical crosslinking processes. The 3D printed, hierarchically interconnected porous structures guide the growth of myofibroblasts, collagen fibers and blood vessels in real 3D scales. In vivo study on those unique smart elastomer scaffolds will help pave the way for personalized and biologically responsive soft tissue implants and implantable devices with better mechanical matches, angiogenesis and tissue integration.
越来越多的证据表明，细胞外基质（ECM）的动态力学性能对组织重塑和再生有调节作用。继我们最近研究了一系列通过间接 3D 打印引导的热致相分离工艺（3D-TIPS）制造的热响应“硬度记忆”弹性体纳米杂化支架后，这项工作报道了这些支架的体外和体内细胞反应，这些支架具有不同的初始硬度和分级互联多孔结构。通过免疫组织化学和组织学评估了在体培养的小鼠胚胎真皮成纤维细胞活力和皮下植入大鼠 3 个月后支架硬度软化过程中的组织反应。具有较高初始硬度和分级多孔结构的支架优于较软的支架，在促进细胞和组织生长之前，为细胞和周围组织提供初始机械支撑，然后在硬度软化过程中促进细胞和组织生长。血管生成贯穿整个数字化打印的互联网络。所有支架都表现出巨噬细胞反应从巨噬细胞表型 I（M1）向巨噬细胞表型 II（M2）的极化，并且随着植入时间的增加，T 细胞增殖反应下调；然而，具有更明显的热响应硬度记忆机制的支架发挥了更高的炎症信息作用。这些结果为具有更好机械匹配、血管生成和组织整合的个性化和生物响应软组织植入物和可植入装置铺平了道路。 意义声明 这项工作报道了一系列通过 3D-TIPS 热响应纳米杂化弹性体支架的细胞反应，这些支架具有不同的硬度软化程度，包括体外和体内大鼠模型。结果首次揭示了支架的初始硬度和动态硬度软化对组织整合、血管生成和炎症反应的影响，而无需耦合化学交联过程。3D 打印的分级互联多孔结构以真实的 3D 尺度引导肌成纤维细胞、胶原纤维和血管的生长。对这些独特的智能弹性体支架的体内研究将有助于为具有更好机械匹配、血管生成和组织整合的个性化和生物响应软组织植入物和可植入装置铺平道路。
