Injectable and bioactive methylcellulose hydrogel carrying bone mesenchymal stem cells as a filler for critical-size defects with enhanced bone regeneration.

As a soluble cellulose derivative, methylcellulose (MC), can be used to construct thermosensitive hydrogels. However, a pure MC gel is generally considered an inert material that is inadequate for cell survival. We adopted an environmentally friendly method to fabricate a nano-hydroxyapatite (nHA) hybrid MC hydrogel. Rheology results showed that the addition of nHA increased the gelation temperature. Furthermore, the live/dead assay confirmed that the addition of nHA improved the survival of bone marrow-derived mesenchymal stem cells (BMSCs) inside the gel. In addition, ARS staining indicated that the presence of nHA stimulated osteogenic differentiation. Finally, in vivo cranial defect experiments showed improved remediation efficiency when using the nHA hybrid MC hydrogel to carry BMSCs.