Research Institute for Biomaterials, Tech Institute for Advanced Materials, Bioinspired Biomedical Materials & Devices Center, College of Materials Science and Engineering, Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Suqian Advanced Materials Industry Technology Innovation Center, Nanjing Tech University, Nanjing 211816, China.
Jiangsu Key Lab of 3D Printing Equipment and Manufacturing, Nanjing Normal University, Nanjing 210046, China.
Acta Biomater. 2023 Oct 1;169:243-255. doi: 10.1016/j.actbio.2023.08.008. Epub 2023 Aug 11.
Despite 3D bioprinting having emerged as an advanced method for fabricating complex in vitro models, developing suitable bioinks that fulfill the opposing requirements for the biofabrication window still remains challenging. Although naturally derived hydrogels can better mimic the extracellular matrix (ECM) of numerous tissues, their weak mechanical properties usually result in architecturally simple shapes and patchy functions of in vitro models. Here, this limitation is addressed by a peptide-dendrimer-reinforced bioink (HC-PDN) which contained the peptide-dendrimer branched PEG with end-grafted norbornene (PDN) and the cysteamine-modified HA (HC). The extensive introduction of ethylene end-groups facilitates the grafting of sufficient moieties and enhances thiol-ene-induced crosslinking, making HC-PDN exhibits improved mechanical and rheological properties, as well as a significant reduction in reactive oxygen species (ROS) accumulation than that of methacrylated hyaluronic acid (HAMA). In addition, HC-PDN can be applied for the bioprinting of numerous complex structures with superior shape fidelity and soft matrix microenvironment. A heterogeneous and biomimetic hepatic tissue is concretely constructed in this work. The HepG2-C3As, LX-2s, and EA.hy.926s utilized with HC-PDN and assisted GelMA bioinks closely resemble the parenchymal and non-parenchymal counterparts of the native liver. The bioprinted models show the endothelium barrier function, hepatic functions, as well as increased activity of drug-metabolizing enzymes, which are essential functions of liver tissue in vivo. All these properties make HC-PDN a promising bioink to open numerous opportunities for in vitro model biofabrication. STATEMENT OF SIGNIFICANCE: In this manuscript, we introduced a peptide dendrimer system, which belongs to the family of hyperbranched 3D nanosized macromolecules that exhibit high molecular structure regularity and various biological advantages. Specifically, norbornene-modified peptide dendrimer was grafted onto PEG, and hyaluronic acid (HA) was selected as a base material for bioink formulation because it is a component of the ECM. Peptide dendrimers confer the following advantages to bioinks: (a) Geometric symmetry can facilitate construction of bioinks with homogeneous networks; (b) abundant surface functional groups allow for abundant crosslinking points; (c) the biological origin can promote biocompatibility. This study shows conceptualization to application of a peptide-dendrimer bioink to extend the Biofabrication Window of natural bioinks and will expand use of 3D bioprinting of in vitro models.
尽管 3D 生物打印已成为制造复杂体外模型的先进方法，但开发满足生物制造窗口相反要求的合适生物墨水仍然具有挑战性。虽然天然衍生的水凝胶可以更好地模拟许多组织的细胞外基质 (ECM)，但其机械性能较弱通常导致体外模型的结构简单和功能不均匀。在这里，通过一种肽 - 树突状聚合物增强的生物墨水（HC-PDN）解决了这一限制，该生物墨水包含了末端接枝降冰片烯的肽 - 树突状聚合物支化聚乙二醇（PDN）和半胱氨酸修饰的透明质酸（HC）。广泛引入乙烯端基有利于接枝足够的部分，并增强硫醇 - 烯诱导的交联，使 HC-PDN 表现出改善的机械和流变性能，以及显著减少活性氧物种（ROS）积累比甲基丙烯酰化透明质酸（HAMA）多。此外，HC-PDN 可用于打印具有卓越形状保真度和软基质微环境的许多复杂结构。本工作具体构建了异质和仿生肝组织。使用 HC-PDN 和辅助 GelMA 生物墨水的 HepG2-C3As、LX-2s 和 EA.hy.926s 紧密模仿了天然肝脏的实质和非实质对应物。生物打印模型显示出内皮屏障功能、肝脏功能以及增加的药物代谢酶活性，这些都是体内肝组织的重要功能。所有这些特性使 HC-PDN 成为一种有前途的生物墨水，为体外模型生物制造开辟了众多机会。
在本文中，我们引入了一种肽树突系统，属于高度支化的 3D 纳米级大分子家族，具有高分子结构规则和各种生物学优势。具体来说，将降冰片烯修饰的肽树突接枝到 PEG 上，选择透明质酸 (HA) 作为生物墨水配方的基础材料，因为它是细胞外基质的组成部分。肽树突赋予生物墨水以下优势：(a) 几何对称性有助于构建具有均匀网络的生物墨水；(b) 丰富的表面官能团允许有丰富的交联点；(c) 生物起源可以促进生物相容性。本研究展示了从概念化到应用肽 - 树突生物墨水来扩展天然生物墨水的生物制造窗口，并将扩展用于体外模型的 3D 生物打印。
