LAUSR

In this study, articular cartilage was decellularized preserving a majority of the inherent proteins, cytokines, growth factors and sGAGs. The decellularized cartilage matrix (dCM) was then encapsulated in poly(lactic acid) microspheres (MS+dCM) via double emulsion. Blank microspheres without dCM, MS(-), were also produced. The microspheres were spherical in shape and protein encapsulation efficiency within MS+dCM was 63.4%. The sustained release of proteins from MS+dCM was observed over 4 weeks in vitro. Both MS+dCM and MS(-) were cytocompatible. The sustained delivery of retained growth factors and cytokines from MS+dCM promoted cell migration in contrast to MS(-). Subsequently, chondrogenesis of hMSCs was upregulated in presence of MS+dCM as evidenced from immunohistochemistry, biochemical quantification and qPCR studies. Specifically, collagen II, aggrecan and SOX 9 gene expression were increased in the presence of MS+dCM by an order or more in magnitude compared to MS(-) with concomitant downregulation of hypertrophic genes (COL X) despite being cultured in the absence of chondrogenic media, (p<0.05). Lastly, microspheres containing alkaline phosphatase (MS+ALP), a surrogate to assess the thermal stability of dCM proteins, incorporated within poly(caprolactone) filaments showed that the enzyme remained functional after filament production by melt extrusion. The establishment of a novel, thermally stable process for producing filaments containing chondroinductive microspheres provides evidence supporting subsequent development of a clinically-relevant, 3D scaffold fabricated from them for osteochondral regeneration and repair.