Exploration of biomaterial-tissue integration in heterogeneous microporous annealed particle scaffolds in subcutaneous implants over 12 months.

Microporous annealed particle (MAP) scaffolds are comprised of hydrogel microparticles with inter- and intra-particle cross-links that provide structure and cell-scale porosity, making them an increasingly attractive option for injectable tissue augmentation. Many current injectable biomaterials create a substantial foreign body response (FBR), while MAP scaffolds mitigate this response and have the potential to facilitate the formation of new tissue, though this de novo tissue formation is poorly understood. Here, we leverage a subcutaneous implant model to explore the maturation of MAP implants with and without heparin microislands (µislands) over one year to identify the effect of bioactive particles on scaffold maturation.

In silico optimization of heparin microislands in microporous annealed particle hydrogel for endothelial cell migration.

Biomaterials capable of generating growth factor gradients have shown success in guiding tissue regeneration, as growth factor gradients are a physiologic driver of cell migration. Of particular importance, a focus on promoting endothelial cell migration is vital to angiogenesis and new tissue formation. Microporous Annealed Particle (MAP) scaffolds represent a unique niche in the field of regenerative biomaterials research as an injectable biomaterial with an open porosity that allows cells to freely migrate independent of material degradation.

Heparin Microislands in Microporous Annealed Particle Scaffolds for Accelerated Diabetic Wound Healing.

Mimicking growth factor-ECM interactions for promoting cell migration is a powerful technique to improve tissue integration with biomaterial scaffolds for the regeneration of damaged tissues. This has been attempted by scaffold-mediated controlled delivery of exogenous growth factors; however, the predetermined nature of this delivery can limit the scaffold's ability to meet each wound's unique spatiotemporal regenerative needs and presents translational hurdles. To address this limitation, we present a new approach to growth factor presentation by incorporating heparin microislands, which are spatially isolated heparin-containing microparticles that can reorganize and protect endogenous local growth factors via heterogeneous sequestration at the microscale and result in functional improvements in wound healing.