Neural tissue engineering: From bioactive scaffolds and in situ monitoring to regeneration

Abstract

Peripheral nerve injury is a large-scale problem that annually affects more than several millions of people all over the world. It remains a great challenge to effectively repair nerve defects. Tissue engineered nerve guidance conduits (NGCs) provide a promising platform for peripheral nerve repair through the integration of bioactive scaffolds, biological effectors, and cellular components. Herein, we firstly describe the pathogenesis of peripheral nerve injuries at different orders of severity to clarify their microenvironments and discuss the clinical treatment methods and challenges. Then, we discuss the recent progress on the design and construction of NGCs in combination with biological effectors and cellular components for nerve repair. Afterward, we give perspectives on imaging the nerve and/or the conduit to allow for the in situ monitoring of the nerve regeneration process. We also cover the applications of different postoperative intervention treatments, such as electric field, magnetic field, light, and ultrasound, to the welldesigned conduit and/or the nerve for improving the repair efficacy. Finally, we explore the prospects of multifunctional platforms to promote the repair of peripheral nerve injury.

Multifluid electrospinning for multi-drug delivery systems: pros and cons, challenges, and future directions

“…Furthermore, these fibers can mimic an extracellular matrix (ECM), which makes electrospinning an attractive method for producing functional materials for tissue engineering and drug delivery. 16,17 There are many different specialized techniques of electrospinning, types of polymers, and process parameters, depending on the desired applications and related kinetics of drug release. One of the biggest challenges currently facing drug delivery system (DDS) design is achieving multiple drug delivery, with the combined delivery of two or more drugs and differing kinetics releases.…”

Combining a Density Gradient of Biomacromolecular Nanoparticles with Biological Effectors in an Electrospun Fiber‐Based Nerve Guidance Conduit to Promote Peripheral Nerve Repair

“…Growth cones at the leading ends of nerve axons can detect and respond to these specific guiding environmental stimuli throughout neuronal development, driving neuronal pathfinding. [ 6 ] The extension of neurites from DRGs after being cultured for 5 days on the different scaffolds was detected. As shown in Figure 5 A , the neurites were extended from both sides of DRGs and oriented in all groups following the direction of fiber alignment.…”

“…[ 5 ] Therefore, it is of great importance and a great challenge as well to develop biologically active NGCs for simultaneously providing multiple induction signals, aiming to improve the microenvironment at the site of injury and promote axonal elongation and functional recovery. [ 4 , 6 ] Currently, various induction signals can be incorporated in scaffolds by designing their structure or morphology as well as loading growth factors and exogenous cells. These induction signals will promote the migration of endogenous cells as well as the regeneration and extension of axons, ultimately realizing nerve regeneration and functional recovery.…”

Electrospun nanofibers for manipulating soft tissue regeneration

“…In addition, real-time monitoring of the regeneration process using modern imaging techniques and combining electrospun fibers with appropriate post-operative interventions, such as electrical stimulation, magnetic stimulation, optical stimulation, acoustic stimulation, and thermal stimulation, may further improve the effects of nerve regeneration. 90…”