A balance between pro-inflammatory and pro-reparative macrophages is observed in regenerative D-MAPS

Microporous annealed particle scaffolds (MAPS) are a new class of granular materials generated through the interlinking of tunable microgels, which produce an interconnected network of void space. These microgel building blocks can be designed with different mechanical or bio-active parameters to facilitate cell infiltration and modulate host response. Previously, changing the chirality of the microgel crosslinking peptides from L- to D-amino acids led to significant tissue regeneration and functional recovery in D-MAPS-treated cutaneous wounds. In this study, we investigated the immunomodulatory effect of D-MAPS in a subcutaneous implantation model. We uncovered how macrophages are the key antigen-presenting cells to uptake and present these biomaterials to the adaptive immune system. A robust linker-specific IgG2b/IgG1 response to D-MAPS was detected as early as 14 days post-implantation. The fine balance between pro-regenerative and pro-inflammatory macrophage phenotypes was observed in D-MAPS as an indicator for regenerative scaffolds. Our work offers valuable insights into the temporal cellular response to synthetic porous scaffolds and establishes a foundation for further optimization of immunomodulatory pro-regenerative outcomes.