Scaffolds mimicking the native structure of tissues

Self-Searching Writing of Human-Organ-Scale Three-Dimensional Topographic Scaffolds with Shape Memory by Silkworm-like Electrospun Autopilot Jet

“…Construction of three-dimensional (3D) scaffolds is important for various applications from nano- to macroscale; − notable examples include functional DNA origami, artificial human organs, 3D-printed houses, and so on . Among these, biomedical applications have attracted intensive attention in recent decades, as genetics and exogenous factors, such as aging, diseases, and injury affecting the human body, highly demand clinical repairs to restore the functions and morphologies of the damaged tissues or organs. − An ideal engineered construct should resemble the native extracellular matrix (ECM), which is an intricate 3D network composed of collagen fibrils and other biomolecules that mainly provide physical and mechanical strength to the tissue and is responsible for diverse biological functions. − Currently, molten extrusion-based 3D printing is the only available technique to produce 3D structures with high fidelity and reproducibility for biomedical applications. ,− In 3D bioprinting, cell and biomaterials are laid in the hydrogel (bioink) form along with the molten synthetic polymer, for example, the FDA-approved poly­(ε-caprolactone) (PCL), primarily used for its exceptional mechanical properties and moderate biodegradability. , These approaches may have constructed scaffolds of shapes mimicking in part or the organ size; however, they become solid as they cure to yield mechanically inflexible and nonstretchable structures that poorly match the physiological conditions of the human body. , The computer-controlled motion produced microarchitectures mostly limited to tessellated grid-like patterns and failed to facilitate 3D cell network formation and vascularization as in native tissues, a necessary feature to carry out the essential biophysical and biochemical functions. ,− Besides, the so-made scaffolds impose high shear stress on cells while occupying a larger area and mass but accommodate lesser cell density, and their poor biodegradability (small surface to volume ratio) affects the tissue regeneration and ECM remodeling within these scaffolds. ,, …”