Grid Efferocytosis via Near-Field Electrostatic Printing Rectifies Skin Immunity

Efferocytosis, by phagocytosing and processing apoptotic cells in injured skin, directly influences the immune microenvironment. However, the comprehensive widespread inflammation and disrupted efferocytosis in injured skin cannot be effectively halted. Herein, “Grid Efferocytosis” strategy within injury site is proposed, which segments the inflammation regulatory into grid microdomains, and further rectifies intra-grid immune microenvironment to accelerate tissue repair. GelMA/PLA/Laponite gridded fiber membranes (GPL) are custom-designed via near-field electrostatic printing, and then coated with HAMA-PBA/EGCG hydrogel by photo-crosslinking and dynamic borate bonding to form a composite fiber membrane (GPL-E). Gridded modulation via GPL-E confines the entire chaotic inflammatory microenvironment into controllable microinflammatory niches. Leveraging the hydrogel coating and boronic ester bond dissociation induced by microenvironmental glucose and reactive oxygen species, GPL-E achieves dynamic anti-glucose and anti-oxidation within microdomains, reconstructing macrophage efferocytosis. Notably, the “grid efferocytosis” recruits repair cells into the grid by magnesium ion release triggered by Laponite exposure on fibers, and enhances endothelial cell vascularization by ≈2.5-fold. In a mouse diabetic ischemic flap model, implantation of grid GPL-E maintains flap-to-base fusion, attenuates inflammatory infiltration & spread, and improves blood perfusion for flap survival. This study demonstrates that “Grid Efferocytosis” rectifies the immune microenvironment, fostering tissue repair and regeneration.