尽管3D生物打印已经成为制造复杂体外模型的先进方法,开发满足生物制造窗口的相反要求的合适的生物墨水仍然具有挑战性。尽管天然来源的水凝胶可以更好地模拟许多组织的细胞外基质(ECM),它们弱的机械性能通常会导致结构简单的形状和体外模型的零散功能。这里,肽-树枝状聚合物增强的生物墨水(HC-PDN)解决了这一限制,该生物墨水包含具有末端接枝降冰片烯(PDN)和半胱胺修饰的HA(HC)的肽-树枝状聚合物支化的PEG。广泛引入乙烯端基促进了足够部分的接枝,并增强了硫醇-烯诱导的交联,使HC-PDN表现出改善的机械和流变性能,以及与甲基丙烯酸酯化透明质酸(HAMA)相比,活性氧(ROS)积累显着减少。此外,HC-PDN可用于生物打印具有优异的形状保真度和软基质微环境的许多复杂结构。在这项工作中,具体构建了异质和仿生的肝组织。HepG2-C3As,LX-2s,和EA。与HC-PDN和辅助GelMA生物墨水一起使用的hy.926s非常类似于天然肝脏的实质和非实质对应物。生物打印的模型显示了内皮屏障功能,肝功能,以及药物代谢酶的活性增加,这是体内肝脏组织的基本功能。所有这些特性使HC-PDN成为有前途的生物墨水,为体外模型生物制造开辟了许多机会。重要声明:在这份手稿中,我们引入了肽树状聚合物系统,超支化三维纳米大分子家族,表现出高分子结构规律性和多种生物学优势。具体来说,降冰片烯修饰的肽树状聚合物接枝到PEG上,选择透明质酸(HA)作为生物墨水制剂的基础材料,因为它是ECM的组分。肽树枝状聚合物赋予生物墨水以下优点:a)几何对称可以促进具有均匀网络的生物墨水的构建;b)丰富的表面官能团允许丰富的交联点;c)生物起源可以促进生物相容性。这项研究显示了肽-树枝状聚合物生物墨水的应用的概念化,以扩展天然生物墨水的生物制造窗口,并将扩大体外模型的3D生物打印的使用。
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.