A novel fabrication of open porous poly-(γ-benzyl-l-glutamate) microcarriers with large pore size to promote cellular infiltration and proliferation

In tissue engineering, porous microcarriers have emerged as cell carriers for the regeneration and repair of tissue defects. It is reported that a large pore size can greatly promote cellular infiltration and proliferation. Therefore, the injectable microcarriers with large pore size are of great value. However, enlarging pore size (>50 μm) of typical microcarriers (200-400 μm) to improve cellular infiltration and proliferation has been a blank research field to date. In the present study, open porous poly-(γ-benzyl-l-glutamate) (PBLG) microcarriers with large pore size (microcarrier size of 200-400 μm and pore size of 70-150 μm) are fabricated from an intermediate product with Janus microspheres feature. The fast organic solvent evaporation and slow gelatin gelation rate in a water-in-oil-in-water (W/O/W) emulsion induced the formation of Janus microspheres with asymmetric composition. The external PBLG shell layer and internal gelatin gel of Janus microspheres could be simply removed to achieve an open and large pore structure. When compared to microcarriers with middle and small pore sizes, the microcarriers with large pore size could drastically promote cellular infiltration and proliferation, indicating a potential towards rapid tissue regeneration and tissue integration.