Nano-layered tendon patch to orchestrate timely interactions between tendon stem/progenitor cells and macrophages.

Abstract

Tendon regeneration remains limited by the unmet challenge of precisely controlling the intensity and duration of local inflammation, often resulting in scarred healing. Here, we present a novel, micro-thin, nano-layered patch that employs Layer-by-Layer (LbL) self-assembly for the precisely controlled release of small molecules, Oxo-M and 4-PPBP, to address this technical challenge. This novel combination of small molecules exhibits distinct functions in modulating the polarization of macrophages and the tenogenic differentiation of tendon stem/progenitor cells (TSCs). The customized, temporal release of these small molecules effectively modulated the critical crosstalk between TSCs and macrophages, thereby promoting regenerative tendon healing. The nano-LbL tendon patch successfully mitigated early inflammation, promoted matrix synthesis, and regulated later tissue remodeling in vivo. Robust scRNA-seq and CellChat analysis delineated the temporal-orchestrated communication between cell types across healing phases, confirming the critical interplays between TSCs, tenocytes, and macrophages. We then validated the key signaling pathways regulating cell-cell communication modulating inflammation. Our nano-layered LbL nanopatch represents a highly translational approach for achieving scarless tendon regeneration. In addition, this study elucidated the essential signaling pathways regulating TSC-macrophage crosstalk, advancing our understanding of tendon biology and pathology.