Characterization of designed directional polylactic acid 3D scaffolds for neural differentiation of human dental pulp stem cells

Abstract

Background/Purpose: In recent years, 3D printing technology has flourished and applied to tissue engineering regeneration. The purpose of this study is to investigate the effects of gap width between struts (GWbS) of three-dimensional-printed polylactic acid scaffolds (3DP-PLASs) on neural differentiation of human dental pulp stem cells (hDPSCs). Methods: Both the 3DP-PLASs with the GWbS of 150 μm and 200 μm were experimental groups and the 3DP-PLAS without microfilament struts was the control group. Properties of 3DP-PLASs were observed by water contact angles (WCA), atomic force microscope (AFM), and differential scanning calorimeter (DSC). The cell culture of hDPSCs on 3DP-PLASs was performed, and cytotoxicities were measured with Alamar Blue assay. The neural differentiation of hDPSCs on different 3DP-PLASs was compared after neural induction. Expressions of neural markers Nestin, MAP2, beta III tubulin, and GFAP were evaluated with immunocytochemical staining. Results: Our results demonstrated no cytotoxicities among scaffolds, whereas they may differ in crystal sizes and directions resulting from different orders of cooling time, contact surface, and temperature distribution during the building process. In addition, hDPSCs could successfully adhere to 3DP-PLAS modified by alcohol or poly-l-Lysine and demonstrate morphological change and related protein performance. Conclusion: We conclude that 3DP-PLASs with 150 μm gaps can induce cellular orientations more easily than those with 200 μm gaps. In addition, 3DP-PLASs seem to improve cell adhesion after being coated with poly-l-lysine or soaked with alcohol. Keywords: Dental pulp stem cell, Three-dimensional-printed polylactic acid scaffolds, Neural differentiation, Atomic force microscope