Regulation of the surface morphology of microspheres by polymers with different crystallinities

Abstract

Poly(trimethylene carbonate) (PTMC), polycaprolactone (PCL), and poly(lactide-co-glycolide) (PLGA) are widely used in the biomedical field due to their excellent biocompatibility and degradability. Particularly, PLGA and PCL, as mature materials, have shown significant application effects in the field of tissue filling. The surface morphology of the filling material has a clear impact on soft tissue filling and collagen regeneration. Here, PLGA, PLGA/PTMC, and PLGA/PCL microspheres with different degrees of crystallinity were prepared using a single emulsion solvent evaporation method. The effect of polymer crystallinity on the surface morphology of the microspheres was systematically studied, and microspheres with different degrees of surface roughness were precisely prepared. This paper reports on five types of microspheres based on PLGA. The properties of amorphous and crystalline blend material prepared microspheres are discussed. The results show that the introduction of amorphous material into PLGA does not affect the surface morphology of the microspheres, but there are significant differences in the crystalline type. The morphology of the microspheres' surface can be effectively controlled by adjusting the number of crystalline segments. Compared with PLGA microspheres, PLGA/PTMC microspheres do not show significant phase separation, while PLGA/PCL microspheres exhibit significant phase separation phenomena, and macroscopically, the surface of the microspheres is rougher. The crystalline type and polymer phase separation jointly affect the morphology of the microspheres. Fluorescence analysis of CCK-8 and L929 cells confirmed that PLGA/PTMC and PLGA/PCL blends have good biocompatibility, and the rough surface morphology significantly improves cell growth. In summary, the PLGA/PCL microspheres prepared by microphase separation technology in this work are promising materials for soft tissue filling.