One-step fabrication of polycaprolactone microparticle-assembled hierarchical and dual-porous films as cell...

Dual-porous biomaterials are particularly interesting in the development of novel cell-supporting matrices. Conventionally, creating dual-porous structures in biomaterials requires combining different types of synthetic routes. In this study, for the first time, one-step natural drying route was proposed to fabricate hierarchical and dual-porous polycaprolactone (PCL) films and their microstructure, formation mechanism, and potentials as cell supporting matrices were investigated. The resulting PCL films were characterized by SEM, XRD, and FTIR instruments. SEM observations showed that PCL films were hierarchically assembled by numerous PCL microparticles with the diameters of around 10 μm and exhibited a dual-porous structure with tailored macropores of 53.7 ± 9.9-141.0 ± 25.0 μm, and micropores of 12.2 ± 3.2-26.2 ± 6.0 μm. Confocal laser scanning microscopy (CLSM) real-time monitoring showed that the formation of the porous structure should be attributed to phase separation of PCL solution during the evaporation of organic solvents under natural condition. XRD patterns showed that the hierarchical and dual-porous PCL films displayed the characteristic diffraction peaks assigned to PCL phase. FT-IR spectra showed that the hierarchical and dual-porous PCL films had characteristic adsorption bands assigned for CO groups. In vitro leaching liquor experiment showed that the hierarchical and dual-porous PCL films were not cytotoxic and showed good biocompatibility. SEM and CLSM observations showed that the hierarchical and dual-porous PCL films supported the adhesion, proliferation, and penetration of two types of mammalian cells: the human umbilical vein endothelial cells and fibroblast L929 cells inside their pores. Thus, the present hierarchical and dual-porous PCL films have potentials as biocompatible cell-supporting matrices.