Vyas Cian, Zhang Jun, Øvrebø Øystein, Huang Boyang, Roberts Iwan, Setty Mohan, Allardyce Benjamin, Haugen Håvard, Rajkhowa Rangam, Bartolo Paulo
Department of Mechanical, Aerospace, and Civil Engineering, University of Manchester, UK.
Institute for Frontier Materials, Deakin University, Australia.
Mater Sci Eng C Mater Biol Appl. 2021 Jan;118:111433. doi: 10.1016/j.msec.2020.111433. Epub 2020 Aug 25.
Polycaprolactone (PCL) scaffolds have been widely investigated for tissue engineering applications, however, they exhibit poor cell adhesion and mechanical properties. Subsequently, PCL composites have been produced to improve the material properties. This study utilises a natural material, Bombyx mori silk microparticles (SMP) prepared by milling silk fibre, to produce a composite to enhance the scaffolds properties. Silk is biocompatible and biodegradable with excellent mechanical properties. However, there are no studies using SMPs as a reinforcing agent in a 3D printed thermoplastic polymer scaffold. PCL/SMP (10, 20, 30 wt%) composites were prepared by melt blending. Rheological analysis showed that SMP loading increased the shear thinning and storage modulus of the material. Scaffolds were fabricated using a screw-assisted extrusion-based additive manufacturing system. Scanning electron microscopy and X-ray microtomography was used to determine scaffold morphology. The scaffolds had high interconnectivity with regular printed fibres and pore morphologies within the designed parameters. Compressive mechanical testing showed that the addition of SMP significantly improved the compressive Young's modulus of the scaffolds. The scaffolds were more hydrophobic with the inclusion of SMP which was linked to a decrease in total protein adsorption. Cell behaviour was assessed using human adipose derived mesenchymal stem cells. A cytotoxic effect was observed at higher particle loading (30 wt%) after 7 days of culture. By day 21, 10 wt% loading showed significantly higher cell metabolic activity and proliferation, high cell viability, and cell migration throughout the scaffold. Calcium mineral deposition was observed on the scaffolds during cell culture. Large calcium mineral deposits were observed at 30 wt% and smaller calcium deposits were observed at 10 wt%. This study demonstrates that SMPs incorporated into a PCL scaffold provided effective mechanical reinforcement, improved the rate of degradation, and increased cell proliferation, demonstrating potential suitability for bone tissue engineering applications.
聚己内酯（PCL）支架已被广泛研究用于组织工程应用，然而，它们表现出较差的细胞粘附性和机械性能。随后，人们制备了PCL复合材料以改善材料性能。本研究利用一种天然材料——通过研磨丝纤维制备的家蚕丝微粒（SMP），来制备一种复合材料以增强支架性能。丝绸具有生物相容性和可生物降解性，且机械性能优异。然而，尚无研究将SMP用作3D打印热塑性聚合物支架中的增强剂。通过熔融共混制备了PCL/SMP（10%、20%、30%重量比）复合材料。流变学分析表明，SMP的加入增加了材料的剪切变稀特性和储能模量。使用基于螺杆辅助挤出的增材制造系统制造支架。利用扫描电子显微镜和X射线显微断层扫描来确定支架形态。支架具有高互连性，其打印纤维规则，孔隙形态在设计参数范围内。压缩力学测试表明，SMP的加入显著提高了支架的压缩杨氏模量。加入SMP后，支架的疏水性增强，这与总蛋白吸附的减少有关。使用人脂肪来源的间充质干细胞评估细胞行为。培养7天后，在较高颗粒负载量（30%重量比）下观察到细胞毒性作用。到第21天，10%重量比的负载量显示出显著更高的细胞代谢活性和增殖、高细胞活力以及细胞在整个支架中的迁移。在细胞培养过程中观察到支架上有钙矿物质沉积。在30%重量比时观察到大量钙矿物质沉积，在10%重量比时观察到较小的钙沉积。本研究表明 incorporated into a PCL scaffold provided effective mechanical reinforcement, improved the rate of degradation, and increased cell proliferation, demonstrating potential suitability for bone tissue engineering applications.（此处原文有误，应改为incorporated into a PCL scaffold provided effective mechanical reinforcement, improved the rate of degradation, and increased cell proliferation, demonstrating potential suitability for bone tissue engineering applications.）将SMP掺入PCL支架可提供有效的机械增强作用，提高降解速率，并增加细胞增殖，表明其在骨组织工程应用中具有潜在的适用性。
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