Biomaterials
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The function of type II collagen in cartilage is well documented and its importance for long bone development has been implicated. However, the involvement of type II collagen in bone marrow derived mesenchymal stem cell (BMSC) osteogenesis has not been well investigated. This study elucidated the pivotal role of type II collagen in BMSC osteogenesis and its potential application to bone healing. ⋯ In a segmental defect model in rats, type II collagen-HA/TCP-implanted rats showed significant callus formation at the reunion site, and a higher SFI (sciatic function index) scoring as comparing to other groups were also observed at 7, 14, and 21 day post-surgery. Collectively, type II collagen serves as a better modulator during early osteogenic differentiation of BMSCs by facilitating RUNX2 activation through integrin α2β1-FAK-JNK signaling axis, and enhance bone defect repair through an endochondral ossification-like process. These results advance our understanding about the cartilaginous ECM-BMSC interaction, and provide perspective for bone defect repair strategies.
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Thermoresponsive polymers (TRPs) have been extensively investigated as smart devices, drug delivery systems and protein conjugates due to their unique phase transition properties. Here, we report the unusual influence of TRPs in blood clotting and the mechanism by which TRPs change the three dimensional organization of blood clot structure. Ten different TRPs with lower critical solution temperatures ranged from 26 to 80 °C are studied. ⋯ The plasma phase of the blood coagulation is not affected in presence of TRPs. We anticipate that our results will have significant implications on the use of TRPs in applications where blood contact is essential. These observations may also open up new avenues, for example, in the design of new generation antithrombotics.