Optimising human bone extracellular matrix derived hydrogels for bone tissue engineering - an analysis of processing parameters

Decellularised tissue provides a promising biological material for tissue regeneration. A central feature of decellularised tissue is the elimination of the cellular components from native tissues while retaining the complex compositions and architecture of extracellular matrix (ECM) [1]. While decellularised ECM hydrogels from bovine and porcine bone tissues have been examined in the field of tissue regeneration [2], to date, no studies have sourced or evaluated decellularised matrices from human bone tissue. The objective of this study was to evaluate the hypothesis that physiochemical and biological properties of ECM hydrogel derived from demineralised and decellularised human bone matrix could be controlled through modulation of bone powder size and digestion time for enhanced bone repair. Trabecular bone from human femoral head samples following hip arthroplasty was collected, and demineralised human bone powders at various sizes (45-250 μm, 250-1000 μm, and 1000-2000 μm) were prepared. After decellularisation, the powders were treated with pepsin solution for 3, 5, and 7 days. The concentration of proteins and gelation strength significantly increased as bone powder size decreased and digestion time increased. Evaluation of cultured human bone marrow-derived stromal cells on the ECM hydrogel derived from 45-250 μm bone powder size and treated for 7 days exhibited significantly enhanced cell proliferation and lineage differentiation. Taken together, a defined digestion time and powder size are crucial factors for generating human bone ECM hydrogels with a high concentration of proteins and rheological properties for augmentation of bone repair