Pollen-inspired multifunctional nanocarrier for porcine circovirus 2 vaccine delivery

Traditional vaccines targeting porcine circovirus type 2 (PCV2) have several limitations, such as low antigen delivery efficiency and inadequate immunogenicity. To address these challenges, this study developed a bionic nanocarrier (Fe₃O₄@MnSiO₃) that synergistically integrates antigen enrichment and immune stimulation functions. Inspired by the hierarchical structure of sunflower pollen, the design constructs composite particles featuring a superparamagnetic Fe₃O₄ core and a mesoporous MnSiO₃ shell, allowing efficient loading and delivery of the PCV2 Cap protein. Owing to its sophisticated biomimetic architecture, the Fe₃O₄@MnSiO₃ particles exhibit a uniform size, porous structure, and excellent biocompatibility. The Fe₃O₄ core facilitates rapid antigen separation and enrichment, while the porous MnSiO₃ shell provides high antigen loading capacity. This composite structure is efficiently internalized by antigen-presenting cells, enabling controlled antigen release within the intracellular microenvironment. Fe₃O₄@MnSiO₃ exhibits outstanding biocompatibility and release performance in vivo, effectively activating immune responses and enhancing immune stimulation through Mn²⁺ release. In vitro and in vivo studies confirm the superior antigen delivery efficiency and immune activation capacity of this nanocarrier system. Collectively, these properties indicate that the engineered Fe₃O₄@MnSiO₃ multifunctional nanocarrier system functions as an effective vehicle for antigen enrichment and delivery, representing a promising therapeutic strategy for control of PCV2 and related diseases.