Abstract:
OBJECTIVE To prepare sporopollenin exine capsules (SECs) from Typhae pollen, evaluate their structural characteristics, biocompatibility, and loading potential for bioactive substances, and provide a reference for their potential clinical applications.
METHODS Different types of Typhae pollen SECs were prepared through defatting and acid/alkali treatments. The porosity and liquid absorption rate of the SECs were determined to evaluate the loading capacity of their internal cavities. The cell adhesion, proliferation, and migration-promoting abilities of the SECs were investigated. On this basis, dandelion-derived extracellular vesicle-like particles (EVLPs) were loaded into SECs using a vacuum-assisted technique. The loading conditions were optimized, and the loading capacities of different SECs were subsequently evaluated.
RESULTS All chemical treatments effectively removed the cytoplasmic components of Typhae pollen and formed hollow structures, among which the KOH-treated SECs exhibited the highest porosity and liquid absorption rate. The KOH-treated SECs promoted cell adhesion and proliferation and enhanced cell migration. The vacuum-assisted loading experiments demonstrated that SECs could efficiently encapsulate dandelion-derived EVLPs. The optimal loading conditions were as follows: vacuum at 0.01 mbar for 5 min, EVLP concentration of 5×109 mL-1, and a pollen(dry weight)-to-EVLP volume ratio of 50 mg∶1 mL. Among different SEC types, the 5% KOH-treated SECs exhibited the highest loading capacity, reaching 1.34 × 109 mg-1.
CONCLUSION Chemical treatment improves the mesoporous internal structure of Typha pollen SECs and endows them with cell proliferation and migration promoting activities. Their excellent loading capacity provides a solid foundation for applications in drug delivery systems.