Górecka Żaneta, Idaszek Joanna, Kołbuk Dorota, Choińska Emilia, Chlanda Adrian, Święszkowski Wojciech
Warsaw University of Technology, Faculty of Material Science and Engineering, Wołoska 141, 02-507 Warsaw, Poland.
Polish Academy of Sciences, Institute of Fundamental Technological Research, Pawińskiego 5b, 02-106 Warsaw, Poland.
Mater Sci Eng C Mater Biol Appl. 2020 Sep;114:111072. doi: 10.1016/j.msec.2020.111072. Epub 2020 May 11.
Fused Deposition Modelling (FDM) technique has been widely utilized in fabrication of 3D porous scaffolds for tissue engineering (TE) applications. Surprisingly, although there are many publications devoted to the architectural features of the 3D scaffolds fabricated by the FDM, none of them give us evident information about the impact of the diameter of the fibres on material properties. Therefore, the aim of this study was to investigate, for the first time, the effect of the diameter of 3D-printed PCL fibres on variations in their microstructure and resulting mechanical behaviour. The fibres made of poly(ε-caprolactone) (PCL) were extruded through commonly used types of nozzles (inner diameter ranging from 0.18 mm to 1.07 mm) by means of FDM technique. Static tensile test and atomic force microscopy working in force spectroscopy mode revealed strong decrease in the Young's modulus and yield strength with increasing fibre diameter in the investigated range. To explain this phenomenon, we conducted differential scanning calorimetry, wide-angle X-ray-scattering, Fourier-transform infrared spectroscopy, infrared and polarized light microscopy imaging. The obtained results clearly showed that the most prominent effect on the obtained microstructures and mechanical properties had different cooling and shear rates during fabrication process causing changes in supramolecular interactions of PCL. The observed fibre size-dependent formation of hydrogen bonds affected the crystalline structure and its stability. Summarising, this study clearly demonstrates that the diameter of 3D-printed fibres has a strong effect on obtained microstructure and mechanical properties, therefore should be taken into consideration during design of the 3D TE scaffolds.
熔融沉积建模（FDM）技术已被广泛应用于制造用于组织工程（TE）应用的三维多孔支架。令人惊讶的是，尽管有许多出版物致力于研究通过FDM制造的三维支架的结构特征，但没有一篇能为我们提供关于纤维直径对材料性能影响的明确信息。因此，本研究的目的是首次研究三维打印聚己内酯（PCL）纤维的直径对其微观结构变化及由此产生的力学行为的影响。通过FDM技术，将聚己内酯（PCL）制成的纤维通过常用类型的喷嘴（内径范围为0.18毫米至1.07毫米）挤出。静态拉伸试验和在力谱模式下工作的原子力显微镜显示，在所研究的范围内，随着纤维直径的增加，杨氏模量和屈服强度显著降低。为了解释这一现象，我们进行了差示扫描量热法、广角X射线散射、傅里叶变换红外光谱、红外和偏振光显微镜成像。所得结果清楚地表明，对所得微观结构和力学性能影响最显著的是制造过程中不同的冷却和剪切速率，这导致了PCL超分子相互作用的变化。观察到的纤维尺寸依赖性氢键形成影响了晶体结构及其稳定性。总之，本研究清楚地表明，三维打印纤维的直径对所得微观结构和力学性能有很大影响，因此在设计三维TE支架时应予以考虑。
