Bio-Scaffolds as Cell or Exosome Carriers for Nerve Injury Repair

Abstract

Central and peripheral nerve injuries can lead to permanent paralysis and organ dysfunction. In recent years, many cell and exosome implantation techniques have been developed in an attempt to restore function after nerve injury with promising but generally unsatisfactory clinical results. Clinical outcome may be enhanced by bio-scaffolds specifically fabricated to provide the appropriate three-dimensional (3D) conduit, growth-permissive substrate, and trophic factor support required for cell survival and regeneration. In rodents, these scaffolds have been shown to promote axonal regrowth and restore limb motor function following experimental spinal cord or sciatic nerve injury. Combining the appropriate cell/exosome and scaffold type may thus achieve tissue repair and regeneration with safety and efficacy sufficient for routine clinical application. In this review, we describe the efficacies of bio-scaffolds composed of various natural polysaccharides (alginate, chitin, chitosan, and hyaluronic acid), protein polymers (gelatin, collagen, silk fibroin, fibrin, and keratin), and self-assembling peptides for repair of nerve injury. In addition, we review the capacities of these constructs for supporting in vitro cell-adhesion, mechano-transduction, proliferation, and differentiation as well as the in vivo properties critical for a successful clinical outcome, including controlled degradation and re-absorption. Finally, we describe recent advances in 3D bio-printing for nerve regeneration.

Molecularly Stimuli-Responsive Self-Assembled Peptide Nanoparticles for Targeted Imaging and Therapy

“…152 The common polypeptide sequences used to construct hydrogels for tissue repair include RGD, IKVAV, YIGSR, and RADA16. 153 IKVAV and YIGSR belong to the laminin-derived peptide motif family, which have major roles in cell attachment, migration, and adhesion. 154 The most significant peptide used to mimic the ECM is RGD, which is originally derived from fibronectin.…”

Exosomes combined with biomaterials in the treatment of spinal cord injury

“…Biomaterials such as hyaluronic acid hydrogel and alginate, have been used to deliver cell-derived exosomes for tissue regeneration, which allowed for sustained and controlled release to improve bioavailability ( Brennan et al, 2020 ) and enhance therapeutic efficacy ( Wang et al, 2019 ; Yuan et al, 2020 ; Murali and Holmes, 2021 ). These biomaterial scaffolds, as alternatives to ECM, need to meet the following: 1) maintain exosomes at the site of injury and preserve their properties and structural characteristics; 2) release exosomes into the ECM for a sufficiently long period of time; and 3) bind to the injured tissue and support the migration of neighboring cells into the scaffold ( Liu et al, 2019 ; Poongodi et al, 2021 ).…”

3D printing of bone and cartilage with polymer materials

“…Chitosan has relatively active free radical groups and is relatively active ( Lee et al, 2013 ; Hafezi et al, 2020 ; Hu et al, 2020 ; Castillo-Henríquez et al, 2021 ). It can also be modified by chemical reagents to prepare corresponding composite materials, further expanding the chitosan application field ( Shen et al, 2020 ; Poongodi et al, 2021 ; Nakielski et al, 2022 ).…”