Halloysite nanotubes coated 3D printed PLA pattern for guiding human mesenchymal stem cells (hMSCs) orientation

Three-dimensional (3D) printed polymer scaffolds can build engineered tissue constructs with complex and hierarchical structures, mechanical and biological heterogeneity. However, the interactions between the scaffolds and cells should be optimally designed for their practical application. In this work, 3D printed polylactic acid (PLA) pattern was functionalized by a polydopamine (PDA) interlayer to firmly bond the halloysite nanotubes (HNTs) on the surfaces of the PLA pattern for guiding cell orientation. A series of 3D printed PLA patterns with different stripe widths were characterized by scanning electron microscopy (SEM), polarized light microscopy (POM), 3D optical profiler and so on. The successful introduction of HNTs on PLA pattern was verified by field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), water contact angle (WCA), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analyzer (TGA). The HNTs coating could effectively improve roughness and hydrophilicity of PLA pattern. In addition, in vitro human mesenchymal stem cells (hMSCs) culture experiments suggested that 3D printed PLA patterns with different strip widths exhibited different ability to induce cell orientation. The smaller the stripe width of the PLA pattern, the more suitable for cell orientation. When the layer height was set to 0.05 mm, the effect of inducing cell orientation was optimal. Meanwhile, the 3D printed PLA pattern with HNTs coating was more suitable for the adhesion and proliferation of cells. This works provides a general routine for improving the cell affinity of 3D printed PLA structure by the simple coating of nanoparticles, which shows the promising application in cell culture scaffolds, wound healing materials, and biosensors.