Figure 4. 3D jet writing scaffolds regenerate bone tissue in vivo.

Two 3 mm defects were placed in the parietal bone of a mouse skull to create a critical bone defect. (A) MicroCT was used to quantify the new bone volume within the defect area. The box plot shows the mean (dot), median (middle line), standard error (top and bottom of the boxes), and the max/min (whiskers) for each group. (*) indicates statistical difference as determined by a Tukey multi-comparison test. (B) 3D reconstruction of the microCT data was performed to visualize the defect area. From top to bottom, sample groups are: hMSCs osteogenically differentiated directly on the scaffold or Os-hMSC, scaffold alone without cells, injection of an equivalent number of non-differentiated hMSCs, and no treatment. (C-F) Histological samples from the calvarial defect model were stained with hemotoxylin (blue, nuclear stain) and eosin (pink, protein stain). When scaffolds with osteogenically differentiated stem cells (Os-hMSC) were implanted, there was significant new bone formation, and PLGA fibers embedded in the new bone are shown in (F). Other groups show that treatment with only a PLGA fiber scaffold implant (E) or hMSC injections (D) yield little to no improvement over no treatment (C). Histology and microCT images are from the best sample for each group. Scale bars represent 3 mm (B), 100 µm (C-F).