Specimens of Tyrannosaurus and colleagues announced the recovery of soft tissue from the marrow cavity of a fossilized leg bone (a 1.15 m long femur), from a 68-million-year-old "Tyrannosaurus". The bone had been intentionally, though reluctantly, broken for shipping and then not preserved in the normal manner, specifically because Schweitzer was hoping to test it for soft tissue. Designated MOR 1125 (and known informally as B-rex), the dinosaur had been excavated from the Hell Creek Formation. Flexible, bifurcating blood vessels and fibrous but elastic bone matrix tissue were recognized. In addition, microstructures resembling blood cells were found inside the matrix and vessels. The
Generative tissue becoming a living tissue. To date, the types of gTissue created can be characterized as variants of soft connective tissues including dermis, tendon, ligament, and fascia. Initially the cell-free ECM biomaterial is implanted and progressively adopted by the host. Immediately upon surgical implantation, the porous material becomes soaked in blood. This seeds the material with a population of circulating stem cells, and growth factors to support gTissue development. As generation progresses, the growth factors, cytokines, and fibrin provisional matrix signals host cells to repopulate the matrix. To support the metabolic activity of these cells, a vascular network is simultaneously created