O-alg-THAM/gel hydrogels functionalized with engineered microspheres based on mesenchymal stem cell secretion recruit endogenous stem cells for cartilage repair

Lacking self-repair abilities, injuries to articular cartilage can lead to cartilage degeneration and ultimately result in osteoarthritis. Tissue engineering based on functional bioactive scaffolds are emerging as promising approaches for articular cartilage regeneration and repair. Although the use of cell-laden scaffolds prior to implantation can regenerate and repair cartilage lesions to some extent, these approaches are still restricted by limited cell sources, excessive costs, risks of disease transmission and complex manufacturing practices. Acellular approaches through the recruitment of endogenous cells offer great promise for in situ articular cartilage regeneration. In this study, we propose an endogenous stem cell recruitment strategy for cartilage repair. Based on an injectable, adhesive and self-healable o-alg-THAM/gel hydrogel system as scaffolds and a biophysio-enhanced bioactive microspheres engineered based on hBMSCs secretion during chondrogenic differentiation as bioactive supplement, the as proposed functional material effectively and specifically recruit endogenous stem cells for cartilage repair, providing new insights into in situ articular cartilage regeneration. [Display omitted] •A supramolecular o-alg-THAM/gel hydrogel with desirable biocompatibility, injectability and adhesiveness was fabricated.•Microspheres of extracellular matrix (ECM) and solidified secretome (MESS) was engineered based on hBMSCs secretion.•Pulsed electromagnetic fields (PEMF) enhanced the quality and biological functions of MESS.•PEMF enhanced MESS (PE-MESS) facilitate stem cell recruitment, migration and aggregation in vitro and in vivo.•PE-MESS laden o-alg-THAM/gel hydrogels enhanced cartilage healing via endogenous stem cells recruitment.