Table 7.

Bone biofabrication using EBB

Authors	Methodology	Major Findings	Limitations
Cui et al., 2016	• ITOP combined with CAD modeling was used to recreate precise vascular and bone tissue complex architecture fabricated with a soft, EC-laden, VEGFincorporated GelMA hydrogel surrounded by a mechanically-rigid PLA scaffold with immobilized BMP-2 ligands	• Printed a patent construct that supported perfusion and stimulated vascular bone formation by coaxing luminal ECs and bulk MSC osteoblastic under flow conditions	• Requires various 3D-bioprinting modalities to generate a biomimetic scaffold with the precise, anatomical bone structure and hierarchical vascular architecture
Kang et al., 2016	• An arbitrary mandibular fragment, derived from a traumatic craniofacial injury, was printed using a hAFSC-laden composite (fibrinogen, gelatin, hyaluronan, and glycerol ) bioink and exposed to osteogenic conditions for 28 days  • Circular implants of hAFSC-laden composite bioinks were printed and preconditioned in defined osteogenic media for 10 days, and subsequently implanted into a murine calvarial defect model for assessment after 5 months	• In the mandibular bone model, matrix calcification was observed upon 28 days of osteogenic differentiation in vitro  • In the calvarial bone model, 5-month explants demonstrated host vascularization, mature bone and osteoid formation, and no necrotic tissue formation	• Tissue-engineered bone architecture that recapitulates the native mandible is important but was not assessed  • Constructs must be able to support host vascular integration for long-term survival, but this was not assessed in this study  • Proper tissue mechanics that are physiologically relevant to the mandible would be necessary to assess the functionality of bioengineered bone
Ahlfeld et al., 2017	• hMSC-encapsulated alginate and methylcellulose bioinks were combined with a nano-silicate clay, Laponite, to print rigid, geometrically complex architectures	• Addition of Laponite to bioink improved printability of hMSC-laden scaffolds with high shape fidelity  • Cell-laden composite bioinks functionalized with the VEGF and BSA promoted optimal hMSC functionality, decreased scaffold stiffness indicative of matrix modification, and increased release of morphogens over 21 days	• Constructs must be equipped with preexisting vasculature to support stable and functional bone tissue replacement for long-term stability
Byambaa et al., 2017	• Print cylindrical filaments of low-efficient GelMA with EBB, encapsulating pericytes and HUVEC in highly-synthesized GelMA, functionalized with pro-osteoblastic silicate nanoparticles and increasing concentrations of VEGF	• Printed highly organized and perfusable bone-like structures that support cell migration, proliferation, osteoblastic differentiation of MSCs, matrix mineralization, colocalization of the HUVEC and pericytes on the lumen wall, and angiogenic sprout lengthening and branching	• Rapid degradation rate of perfused GelMA constructs limits its use for long-term studies, indicating that composite bioinks that maintain their mechanical robustness over an extended period of time will be required for tissue stability and functionality