One-step preparation of macroporous zein microspheres by solvent diffusion for dye adsorption

Macroporous microspheres have attracted significant interest in various fields since macropores endow with fast mass transfer. However, constructing the macropore mostly requires additional porogenic agents and complex steps. Here, a simple solvent diffusion strategy has been developed for the rapid preparation of macroporous protein microspheres. Based on the strategy, the macropores in the microspheres are created by the removal of the trapped aqueous phase. The results show that the average particle size of the prepared microspheres is centered at about 10 µm. The pore size of the microspheres ranges from 50 nm to about 1 µm and can be controlled by adjusting the parameters of surfactant, temperature, and concentration during the preparation process for different requirements. Finally, the macropore microspheres are characterized by the adsorption of Congo red dyes, which show excellent adsorption ability. According to these results, these macroporous protein microspheres have a practical potential for applications in adsorption and biomedicine fields.