Ferreira Joana, Gloria Antonio, Cometa Stefania, Coelho Jorge F J, Domingos Marco
Centre for Rapid and Sustainable Product Development, Polytechnic Institute of Leiria, Leiria - Portugal.
Institute of Polymers, Composites and Biomaterials, National Research Council of Italy, Naples - Italy.
J Appl Biomater Funct Mater. 2017 Jul 27;15(3):e185-e195. doi: 10.5301/jabfm.5000363.
In recent years, the tissue engineering (TE) field has significantly benefited from advanced techniques such as additive manufacturing (AM), for the design of customized 3D scaffolds with the aim of guided tissue repair. Among the wide range of materials available to biomanufacture 3D scaffolds, poly(ε-caprolactone) (PCL) clearly arises as the synthetic polymer with the greatest potential, due to its unique properties - namely, biocompatibility, biodegradability, thermal and chemical stability and processability. This study aimed for the first time to investigate the effect of pore geometry on the in vitro enzymatic chain cleavage mechanism of PCL scaffolds manufactured by the AM extrusion process.
Methods: Morphological properties of 3D printed PCL scaffolds before and after degradation were evaluated using Scanning Electron Microscopy (SEM) and micro-computed tomography (μ-CT). Differential Scanning Calorimetry (DSC) was employed to determine possible variations in the crystallinity of the scaffolds during the degradation period. The molecular weight was assessed using Size Exclusion Chromatography (SEC) while the mechanical properties were investigated under static compression conditions.
Morphological results suggested a uniform reduction of filament diameter, while increasing the scaffolds' porosity. DSC analysis revealed and increment in the crystallinity degree while the molecular weight, evaluated through SEC, remained almost constant during the incubation period (25 days). Mechanical analysis highlighted a decrease in the compressive modulus and maximum stress over time, probably related to the significant weight loss of the scaffolds.
All of these results suggest that PCL scaffolds undergo enzymatic degradation through a surface erosion mechanism, which leads to significant variations in mechanical, physical and chemical properties, but which has little influence on pore geometry.
近年来，组织工程（TE）领域从增材制造（AM）等先进技术中受益匪浅，这些技术用于设计定制的3D支架，以引导组织修复。在可用于生物制造3D支架的多种材料中，聚（ε-己内酯）（PCL）因其独特的性能——即生物相容性、生物降解性、热稳定性和化学稳定性以及可加工性，显然成为最具潜力的合成聚合物。本研究首次旨在研究孔隙几何形状对通过AM挤出工艺制造的PCL支架体外酶促链裂解机制 的影响。
使用扫描电子显微镜（SEM）和微计算机断层扫描（μ-CT）评估3D打印PCL支架降解前后的形态学特性。采用差示扫描量热法（DSC）确定降解期间支架结晶度的可能变化。使用尺寸排阻色谱法（SEC）评估分子量，同时在静态压缩条件下研究机械性能。
形态学结果表明长丝直径均匀减小，同时支架孔隙率增加。DSC分析显示结晶度增加，而通过SEC评估的分子量在孵育期（25天）内几乎保持恒定。力学分析强调压缩模量和最大应力随时间降低，这可能与支架的显著重量损失有关。
所有这些结果表明，PCL支架通过表面侵蚀机制进行酶促降解，这导致机械、物理和化学性质发生显著变化，但对孔隙几何形状影响很小。
