Fig. 5

The CG/PHA/5%PBT piezoelectric hydrogel promotes bone tissue regeneration in vivo. a 2D micro-CT coronal and sagittal images, and the BV/TV and BMD results of regenerated bone tissues. Scale bar: 200 μm. b HE, Masson’s trichrome, and Goldner’s trichrome staining of the bone defect 8 weeks after implantation. Scale bar: 200 μm. Yellow arrows and black arrows represent the newly formed central canal and bone lacunae within the defect region, respectively. For Goldner’s trichrome staining images, a small island of immature bone (osteoid, red) was detected at the periphery of the defect site in the control group. Black dotted lines define the boundary of the critical-sized cranial bone defect. ^*P < 0.05, compared with the control group; ^#P < 0.05, compared with the CG group; ^$P < 0.05, compared with the CG/PHA group. CG chitosan/gelatin, PHA polydopamine coated-hydroxyapatite, PBT polydopamine coated-barium titanate, BV/TV bone tissue volume/total tissue volume, BMD bone mineral density, FT fibrous tissue, NB newly formed bone tissue, HB host bone, MB mineralized/mature bone