Harnessing the Power of Nature: Monodisperse Pickering Emulsion Droplets and Yolk-Shell Microcapsules Utilizing Bee Pollen Particles

The preparation of monodisperse Pickering emulsions currently can only be achieved using microfluidics or membrane emulsification, limiting its widespread applications in many fields. Here, by simply introducing naturally occurring pollen grains during mechanical emulsification, it becomes extremely feasible to fabricate uniform Pickering emulsions. The process of shearing and turbulence leads to a constant reduction in the size of the droplets of the dispersed phase. The robust exine of the pollen grains in the continuous phase enables them to retain their structural integrity during emulsification, resulting in the formation of a single pollen-in-water-in-oil structure. Meanwhile, the intrinsic monodispersity of the pollen grains allows for the resulting emulsions to be similarly uniform, and they can be easily collected through centrifugation. As a result, this novel methodology achieves the effective formulation of monodisperse Pickering emulsions in an unprecedented way. Furthermore, the utilization of sporopollenin exine capsules (SECs) as a replacement for pollen, in conjunction with sol–gel interfacial engineering, enables the attainment of “yolk-shell” dual-shell microcapsules. This approach not only effectively addresses the issue of cargo leakage in SECs but also imparts exceptional uniformity and stability to the microcapsules.