Biomaterials and Biomedical Engineering Research Laboratory, Department of Metallurgical, Materials and Biomedical Engineering, University of Texas at El Paso, El Paso, TX, USA.
J Tissue Eng Regen Med. 2018 Apr;12(4):1133-1144. doi: 10.1002/term.2614. Epub 2017 Dec 10.
We have designed a unique injectable bioactive hydrogel comprising of alginate, gelatin, and nanocrystalline hydroxyapatite and loaded with osteoblasts, with the ability to infiltrate into three-dimensional Ti-6Al-4V scaffolds with interconnected porous architecture, fabricated by electron beam melting. A two-step crosslinking process using the EDC/NHS and CaCl was adopted and found to be effective in the fabrication of cell-loaded hydrogel/Ti-6Al-4V scaffold system. This hybrid Ti-6Al-4V scaffold/hydrogel system was designed for the reconstruction of bone defects, which are difficult to heal in the absence of suitable support materials. The hybrid Ti-6Al-4V/hydrogel system favourably modulated the biological functions, namely, adhesion, proliferation, cell-to-cell, and cell-material communication because of the presence of extracellular matrix-like hydrogel in the interconnected porous structure of 3D printed Ti-6Al-4V scaffold. The hydrogel was cytocompatible, which was proven through live/dead assay, the expression level of prominent proteins for cell adhesion and cytoskeleton, including 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay. Furthermore, the high bone formation ability of the hydrogel was confirmed using alkaline phosphatase assay. A high equilibrium water content (~97%) in the hydrogel enables the delivery of cells and bioactive molecules, necessary for bone tissue growth. Although not studied, the presence of hydrogel in the pores of the scaffold can provide the space for the cell migration as well as vascularization through it, required for the effective exchange of nutrients. In conclusion, we underscore that the 3D-printed Ti-6Al-4V scaffold-loaded with bioactive hydrogel to treat the bone defects significantly impacted cellular functions and cell-material interaction.
我们设计了一种独特的可注射生物活性水凝胶，由海藻酸钠、明胶和纳米晶羟基磷灰石组成，并负载成骨细胞，能够渗透到具有互连多孔结构的三维 Ti-6Al-4V 支架中，该支架由电子束熔化制造而成。采用 EDC/NHS 和 CaCl 的两步交联工艺，发现该工艺在制备负载细胞的水凝胶/Ti-6Al-4V 支架系统中非常有效。这种混合 Ti-6Al-4V/水凝胶系统旨在重建骨缺损，在没有合适的支撑材料的情况下，这些骨缺损难以愈合。由于 3D 打印 Ti-6Al-4V 支架的互连多孔结构中存在细胞外基质样水凝胶，混合 Ti-6Al-4V/水凝胶系统有利于调节生物功能，即细胞黏附、增殖、细胞间和细胞-材料通讯。水凝胶具有细胞相容性，通过活/死检测、细胞黏附和细胞骨架的突出蛋白表达水平（包括 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（MTT）测定）得到证实。此外，通过碱性磷酸酶测定证实了水凝胶具有很高的成骨能力。水凝胶中的高平衡含水量（~97%）可实现细胞和生物活性分子的输送，这是骨组织生长所必需的。虽然没有研究，但支架孔中的水凝胶可以为细胞迁移和通过它的血管化提供空间，这是有效交换营养物质所必需的。总之，我们强调，负载生物活性水凝胶的 3D 打印 Ti-6Al-4V 支架治疗骨缺损显著影响细胞功能和细胞-材料相互作用。
