Biomimetic Tertiary Lymphoid Structures with Microporous Annealed Particle Scaffolds for Cancer Postoperative Therapy

Immunotherapy plays a vital role in cancer postoperative treatment. Strategies to increase the variety of immune cells and their sustainable supply are essential to improve the therapeutic effect of immune cell-based immunotherapy. Here, inspired by tertiary lymphoid structures (TLSs), we present a microfluidic-assisted microporous annealed particle (MAP) scaffold for the persistent recruitment of diverse immune cells for cancer postoperative therapy. Based on the thermochemical responsivity of gelatin methacryloyl (GelMA), the MAP scaffold was fabricated by physical cross-linking and sequential photo-cross-linking of GelMA droplets, which were prepared by microfluidic electrospraying. Due to the encapsulation of liquid nitrogen-inactivated tumor cells and immunostimulant, the generated MAP scaffold could recruit a large number of immune cells, involving T cells, macrophages, dendritic cells, B cells, and natural killer cells, thereby forming the biomimetic TLSs in vivo. In addition, by combination of immune checkpoint inhibitors, a synergistic anticancer immune response was provoked to inhibit tumor recurrence and metastasis. These properties make the proposed MAP scaffold-based artificial TLSs of great value for efficient cancer postoperative therapy.