One‐Step Fabrication of Uniform Biodegradable Microbeads with Unimodal and Bimodal Porous Structures Using Spontaneous Microphase Separation

Abstract

AbstractUniform poly(l‐lactic acid) (PLLA) microbeads with unimodal or bimodal porous structures are fabricated using a simple fluidic device based on a single oil‐in‐water emulsion method, where an alkane (octane, undecane, tridecane, and pentadecane) serves as the porogen. During the solvent evaporation, the alkanes spontaneously undergo a microphase separation, resulting in a highly porous structure. The size and size distribution of the pores in the PLLA microbeads can be easily controlled by changing the alkane type and concentration. When the undecane, tridecane, and pentadecane are used as the porogen at 6 wt%, the PLLA microbeads have the bimodal porous structure with a large hollow pore in the center and many small pores. In vitro and in vivo studies reveal that those PLLA microbeads with the bimodal porous structure readily facilitate the penetration and proliferation of cells and host tissues compared with the other PLLA microbeads. These results indicate that the superior properties of PLLA porous microbeads with a bimodal porous structure are suitable for diverse biomedical applications such as tissue engineering, cell delivery, and plastic surgery.