Objective: To explore the effect of NaOH on the surface morphology of three-dimensional (3D) printed poly- L-lactic acid (PLLA) mesh scaffolds.
Methods: The 3D printed PLLA mesh scaffolds were prepared by fused deposition molding technology, then the scaffold surfaces were etched with the NaOH solution. The concentrations of NaOH solution were 0.01, 0.1, 0.5, 1.0, and 3.0 mol/L, and the treatment time was 1, 3, 6, 9, and 12 hours, respectively. There were a total of 25 concentration and time combinations. After treatment, the microstructure, energy spectrum, roughness, hydrophilicity, compressive strength, as well as cell adhesion and proliferation of the scaffolds were observed. The untreated scaffolds were used as a normal control.
Results: 3D printed PLLA mesh scaffolds were successfully prepared by using fused deposition molding technology. After NaOH etching treatment, a rough or micro porous structure was constructed on the surface of the scaffold, and with the increase of NaOH concentration and treatment time, the size and density of the pores increased. The characterization of the scaffolds by energy dispersive spectroscopy showed that the crystal contains two elements, Na and O. The surface roughness of NaOH treated scaffolds significantly increased ( P<0.05) and the contact angle significantly decreased ( P<0.05) compared to untreated scaffolds. There was no significant difference in compressive strength between the untreated scaffolds and treated scaffolds under conditions of 0.1 mol/L/12 h and 1.0 mol/L/3 h ( P>0.05), while the compression strength of the other treated scaffolds were significantly lower than that of the untreated scaffolds ( P<0.05). After co-culturing the cells with the scaffold, NaOH treatment resulted in an increase in the number of cells on the surface of the scaffold and the spreading area of individual cells, and more synapses extending from adherent cells.
Conclusion: NaOH treatment is beneficial for increasing the surface hydrophilicity and cell adhesion of 3D printed PLLA mesh scaffolds.
目的: 探讨NaOH蚀刻对3D打印聚左旋乳酸（poly- L-lactic acid，PLLA）网状支架表面形貌的影响。.
方法: 采用熔融沉积成型技术制备3D打印PLLA网状支架，并采用NaOH溶液对支架表面进行蚀刻处理；NaOH溶液浓度分别为0.01、0.1、0.5、1.0、3.0 mol/L，处理时间分别为1、3、6、9、12 h，共25种浓度/时间组合。处理后对支架微观形貌、能谱元素、表面粗糙度、亲水性、压缩强度以及细胞黏附、增殖等方面进行观测。以未处理支架作为正常对照。.
结果: 通过熔融沉积成型技术成功制备3D打印PLLA网状支架。经NaOH蚀刻处理构建了粗糙或微观孔洞状结构支架表面，且随NaOH浓度及处理时间增加，孔径及孔密度随之增加。能量色散光谱对样品表征显示材料表面晶体含有Na、O两种元素。经NaOH处理支架表面粗糙度均较未处理支架增加（ P<0.05）、接触角减小（ P<0.05）；0.1 mol/L/12 h、1.0 mol/L/3 h处理支架压缩强度与未处理支架差异无统计学意义（ P>0.05）, 其余处理支架压缩强度均小于未处理支架（ P<0.05）。细胞与支架共培养后，NaOH处理支架表面细胞增多，单个细胞铺展面积增大，黏附细胞伸出突触更多。.
结论: NaOH处理3D打印PLLA网状支架有利于增加支架表面亲水性及细胞黏附。.
Keywords: NaOH; Poly-L-lactic acid; cell adhesion; hydrophilicity; mesh scaffold; three-dimensional printing.