A Magnetically Driven Biodegradable Microsphere with Mass Production Capability for Subunit Vaccine Delivery and Enhanced Immunotherapy

Subunit vaccines have emerged as a promising strategy in immunotherapy for combating viral infections and cancer. Nevertheless, the clinical application of subunit vaccines is hindered by limitations in antigen delivery efficiency, characterized by rapid clearance and inadequate cellular uptake. Here, a novel subunit vaccine delivery system utilizing ovalbumin@magnetic nanoparticles (OVA@MNPs) encapsulated within biodegradable gelatin methacryloyl (GelMA) microspheres was proposed to enhance the efficacy of antigen delivery. OVA@MNPs-loaded GelMA microspheres, denoted as OMGMs, can be navigated through magnetic fields to deliver subunit vaccines into the lymphatic system efficiently. Moreover, the biodegradable OMGMs enabled the sustained release of subunit vaccines, concentrating OVA around lymph nodes and enhancing the efficacy of induced immune response. OMGMs were produced through a microfluidic droplet generation technique, enabling mass production. In murine models, OMGMs successfully accumulated antigens in lymph nodes abundant in antigen-presenting cells, leading to enhanced cellular and humoral immunity and pronounced antitumor effects with a single booster immunization. In conclusion, these findings highlight the promise of OMGMs as a practical subunit vaccination approach, thus addressing the limitations associated with antigen delivery efficiency and paving the way for advanced immunotherapeutic strategies.