The injected solution undergoes self-assembly or curing reaction to crosslink the polymer forming a 3D scaffold. The scaffold is designed to resemble natural trabecular bone extracellular matrix that can provide mechanical support and have interconnecting microporosity which gives a favorable environment for cell attachment, migration, proliferation, and differentiation . It allows the mass transport of oxygen, nutrients, and cellular infiltration throughout the scaffold . Nowadays, 4D bioprinting is extensively used to produce channels in the scaffold, using sacrificial polymers, for vascularization and mass transfer . Mainly, gelatin and agarose are used to fill the cavities which can then be degraded using external stimuli like heating in this case .