Search for: All records

Injuries to the peripheral nervous system are a common clinical issue, causing dysfunctions of the motor and sensory systems. Surgical interventions such as nerve autografting are necessary to repair damaged nerves. Even with autografting, i.e., the gold standard, malfunctioning and mismatches between the injured and donor nerves often lead to unwanted failure. Thus, there is an urgent need for a new intervention in clinical practice to achieve full functional recovery. Nerve guidance conduits (NGCs), providing physicochemical cues to guide neural regeneration, have great potential for the clinical regeneration of peripheral nerves. Typically, NGCs are tubular structures with various configurations to create a microenvironment that induces the oriented and accelerated growth of axons and promotes neuron cell migration and tissue maturation within the injured tissue. Once the native neural environment is better understood, ideal NGCs should maximally recapitulate those key physiological attributes for better neural regeneration. Indeed, NGC design has evolved from solely physical guidance to biochemical stimulation. NGC fabrication requires fundamental considerations of distinct nerve structures, the associated extracellular compositions (extracellular matrices, growth factors, and cytokines), cellular components, and advanced fabrication technologies that can mimic the structure and morphology of native extracellular matrices. Thus, this review mainly summarizes the recent advances in the state-of-the-art NGCs in terms of biomaterial innovations, structural design, and advanced fabrication technologies and provides an in-depth discussion of cellular responses (adhesion, spreading, and alignment) to such biomimetic cues for neural regeneration and repair. 

Abstract The fields of tissue engineering and regenerative medicine have made astounding progress in recent years, evidenced by cutting‐edge 4D printing technologies, precise gene editing tools, and sustained long‐term functionality of engineered tissue grafts. Despite these fantastic feats, the clinical success of tissue‐engineered constructs so far remains limited to only those relatively simple types of tissues such as thin bilayer skin equivalents or avascular cartilage. On the other hand, volumetric tissues (larger than a few millimeters in all dimensions), which are highly desirable for clinical utility, suffer from poor oxygen supply due to limited dimensional diffusion. Notably, large, complex tissues typically require a vascular network to supply the growing cells with nutrients for metabolic demands to prolong viability and support tissue formation. In recognition, extensive efforts have been made to create vascular‐like networks in order to facilitate mass exchange through volumetric scaffolds. This review underlines the urgent need for continued research to create more complex and functional vascular networks, which is crucial for generating viable volumetric tissues, and highlights the recent advances in sacrificial template‐enabled formation of vascular‐like networks.