Biofabrication of nanocomposite-based scaffolds containing human bone extracellular matrix for the differentiation of skeletal stem and progenitor cells

Autograft or metal implants are routinely used in skeletal repair but can fail to provide a long-term clinical resolution, emphasising the need for a functional biomimetic tissue engineering alternative. An attractive sustainable opportunity for tissue regeneration would be the application of human bone waste tissue for the synthesis of a material ink for 3D bioprinting of skeletal tissue. The use of human bone extracellular matrix (bone-ECM) offers an exciting potential for the development of an appropriate micro-environment for human bone marrow stromal cells (HBMSCs) to proliferate and differentiate along the osteogenic lineage. Extrusion-based deposition was mediated by the blending of human bone-ECM (B) with nanoclay (L, Laponite(R)) and alginate (A) polymer, to engineer a novel material ink (LAB). The inclusion of nanofiller and polymeric material increased the rheological, printability, and drug retention properties and, critically, the preservation of HBMSCs viability upon printing. The composite human bone-ECM-based 3D constructs containing vascular endothelial growth factor (VEGF) enhanced vascularisation following implantation in an ex vivo chick chorioallantoic membrane (CAM) model. Addition of bone morphogenetic protein-2 (BMP-2) with HBMSCs further enhanced vascularisation together with mineralisation after only 7 days. The current study demonstrates the synergistic combination of nanoclay with biomimetic materials, (alginate and bone-ECM) to support the formation of osteogenic tissue both in vitro and ex vivo and offers a promising novel 3D bioprinting approach to personalised skeletal tissue repair. Graphical AbstractEngineering nanoclay-based bone ECM novel bioink for bone regeneration. Human bone trabecular tissue was demineralised, decellularised and blended with nanoclay (Laponite(R)) and alginate after digestion. The resulting ink was investigated for printability following rheological and filament fusion investigation. The microstructural arrangement of the blends was examined together with viability and functionality of bioprinted HBMSCs. Finally, the ability of the novel blend to support drug release ex vivo in a CAM model was determined confirming the potential of the bone ECM ink to support bone formation. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=191 SRC="FIGDIR/small/536074v1_ufig1.gif" ALT="Figure 1"> View larger version (64K): org.highwire.dtl.DTLVardef@b9dc13org.highwire.dtl.DTLVardef@1f6f0dorg.highwire.dtl.DTLVardef@1b3c098org.highwire.dtl.DTLVardef@295192_HPS_FORMAT_FIGEXP M_FIG C_FIG