McNamara Stephanie L, McCarthy Ethan M, Schmidt Daniel F, Johnston Stephen P, Kaplan David L
Department of Biomedical Engineering, Tufts University, Medford, MA, USA; Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.
Department of Plastics Engineering, University of Massachusetts Lowell, Lowell, MA, USA.
Biomaterials. 2021 Feb;269:120643. doi: 10.1016/j.biomaterials.2020.120643. Epub 2021 Jan 2.
Traditional bone fixation devices made from inert metal alloys provide structural strength for bone repair but are limited in their ability to actively promote bone healing. Although several naturally derived bioactive materials have been developed to promote ossification in bone defects, it is difficult to translate small-scale benchtop fabrication of these materials to high-output manufacturing. Standard industrial molding processes, such as injection and compression molding, have typically been limited to use with synthetic polymers since most biopolymers cannot withstand the harsh processing conditions involved in these techniques. Here we demonstrate injection and compression molding of a bioceramic composite comprised of hydroxyapatite (HA) and silk fibroin (SF) from Bombyx mori silkworm cocoons. Both the molding behavior of the HA-SF slurry and final scaffold mechanics can be controlled by modulating SF protein molecular weight, SF content, and powder-to-liquid ratio. HA-SF composites with up to 20 weight percent SF were successfully molded into stable three-dimensional structures using high pressure molding techniques. The unique durability of silk fibroin enables application of common molding techniques to fabricate composite silk-ceramic scaffolds. This work demonstrates the potential to move bone tissue engineering one step closer to large-scale manufacturing of natural protein-based resorbable bone grafts and fixation devices.
由惰性金属合金制成的传统骨固定装置为骨修复提供结构强度，但在积极促进骨愈合方面能力有限。尽管已经开发了几种天然衍生的生物活性材料来促进骨缺损处的骨化，但将这些材料的小规模实验室制造转化为高产量制造却很困难。标准的工业成型工艺，如注塑成型和压缩成型，通常仅限于与合成聚合物一起使用，因为大多数生物聚合物无法承受这些技术所涉及的苛刻加工条件。在此，我们展示了一种由羟基磷灰石（HA）和家蚕茧丝素蛋白（SF）组成的生物陶瓷复合材料的注塑成型和压缩成型。通过调节丝素蛋白分子量、丝素蛋白含量和粉液比，可以控制HA-SF浆料的成型行为和最终支架力学性能。使用高压成型技术成功地将含高达20重量百分比丝素蛋白的HA-SF复合材料模塑成稳定的三维结构。丝素蛋白独特的耐久性使得可以应用常见的成型技术来制造复合丝-陶瓷支架。这项工作展示了将骨组织工程向大规模制造基于天然蛋白质的可吸收骨移植材料和固定装置推进一步的潜力。
