Abstract:Herein, high interconnected porous characteristics of poly(high internal phase emulsion) (PolyHIPE) and good biocompatibility of poly(ε-caprolactone) (PCL) were combined to create 3D porous polyester-based PolyHIPE scaffolds. First, ring opening polymerization (ROP) of ε-caprolactone (CL) and 4-methyl-ε-caprolactone (MeCL) using benzenedimethanol as initiator and Sn(Oct)2 as catalyst were carried out, followed by fully acrylation of both hydroxyl ends. Then, emulsifier Hypermer T96 was used to emulsify the dichloromethane/water mixing system to obtain high internal phase emulsion (HIPE, internal volume >74%), where pentaerythritol tetra(3-mercaptopropionate) (PETMP) was added afterwards. Finally, under UV light irradiating, thiol-ene click cross-linking took place in continuous phase to form high interconnected porous polyester-based PolyHIPE scaffolds. The structure of PCL or poly(4-methyl-ε-caprolactone) (PMCL) and double-bond conversion of the polymers were firstly characterized by nuclear magnetic resonance (1H-NMR) and gel permeation chromatography (GPC). Then, the cross-linking conditions of PolyHIPE were also studied, and scanning electron microscopy (SEM), differential scanning calorimeter (DSC) and universal material tester were used to characterize the microstructure, thermodynamics and mechanical properties of the PolyHIPE porous scaffolds, respectively. Lastly, the biological properties of the scaffolds were further evaluated by cytotoxicity assessment and hepatocyte culture experiment in vitro. The results of 1H-NMR and GPC showed that the synthesis and terminal functionalization of PCL and PMCL were successfully achieved. From the results of cross-linking conditions of HIPE and mechanical properties of PolyHIPE, the stability of emulsion could be adjusted by the molecular weight of PCL or PMCL, the water content and temperature of internal phase. Furthermore, the water temperature of HIPE had great influence on the performances of PolyHIPE. The higher the water temperature in HIPE, the lower stiffness the scaffold. From cytotoxicity assessment and hepatocyte culture in vitro, it was found that Soxhlet-extracted PolyHIPE scaffolds were almost non-toxic, and the lower stiffness of the scaffold was beneficial for proliferation and function express of hepatocytes.