Additive Manufacturing Laboratory, Faculty of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran.
Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
J Biomater Appl. 2023 Oct;38(4):484-499. doi: 10.1177/08853282231202734. Epub 2023 Oct 8.
In this study, 3D printing of poly-l-lactic acid (PLLA) scaffolds reinforced with graphene oxide (GO) nanoparticles via Digital Light Processing (DLP) was investigated to mimic bone tissue. Stereolithography is one of the most accurate additive manufacturing methods, but the dominant available materials used in this method are toxic. In this research, a biocompatible resin (PLLA) was synthetized and functionalized to serve the purpose. Due to the low mechanical properties of the printed product with the neat resin, graphene oxide nanoparticles in three levels (0.5, 1, and 1.5 wt%) were added with the aim of enhancing the mechanical properties. At first, the optimum post cure time of the neat resin was investigated. Consequently, all the parts were post-cured for 3 h after printing. Due to the temperature-dependent structure of GO, all samples were placed in an oven at 85°C for different time periods of 0, 6, 12, and 18 h to increase mechanical properties. The compression test of heat-treated samples reveals that the compressive strength of the printed parts containing 0.5,1, and 1.5% of GO increased by 151,162 ad 235%, respectively. Scaffolds with the designed pore sizes of 750 microns and a porosity of 40% were printed. Surface hydrophilicity test was performed for all samples showing that the hydrophilicity of the samples increased with increasing GO percentage. The degradation behavior of the samples was evaluated in a PBS environment, and it revealed that by increasing GO, the rate of component degradation increased, but the heat treatment had the opposite effect and decreased the degradation rate. Finally, besides improving biological properties, a significant increase in mechanical properties under compression can introduce the printed scaffolds as a suitable option for bone implants.
在这项研究中，通过数字光处理（DLP）对聚-l-乳酸（PLLA）支架进行了 3D 打印，其中加入了氧化石墨烯（GO）纳米粒子进行增强，以模拟骨组织。立体光刻是最精确的增材制造方法之一，但该方法中使用的主要材料是有毒的。在这项研究中，合成并功能化了一种生物相容性树脂（PLLA）来满足这一目的。由于纯树脂打印产品的机械性能较低，因此添加了氧化石墨烯纳米粒子（含量分别为 0.5%、1%和 1.5%），以提高机械性能。首先，研究了纯树脂的最佳后固化时间。因此，所有零件在打印后都要后固化 3 小时。由于 GO 的结构随温度而变化，所有样品都在 85°C 的烘箱中放置不同时间（0、6、12 和 18 小时），以提高机械性能。对热处理样品的压缩试验表明，含 0.5%、1%和 1.5%GO 的打印零件的抗压强度分别提高了 151%、162%和 235%。打印了设计孔径为 750 微米、孔隙率为 40%的支架。对所有样品进行了表面亲水性能测试，结果表明样品的亲水性随 GO 百分比的增加而增加。在 PBS 环境下评价了样品的降解行为，结果表明，随着 GO 的增加，组件的降解速率增加，但热处理则相反，降低了降解速率。最后，除了改善生物性能外，压缩下机械性能的显著提高可以使打印支架成为骨植入物的一个合适选择。
