Triiodothyronine-loaded hybrid nanofibrous scaffold for spinal cord tissue engineering

Introduction Spinal cord injury (SCI) is one of the most challenging issues in regenerative medicine and tissue engineering. Due to the micro environment of the site of injury in SCI, regeneration process is restricted. Scaffolds can be used to fill the gap at the site of injury, to stabilize the spine, and to inhibit the growth of connective tissue in spinal cord tissue. Moreover, it can stimulate axonal outgrowth and remylination of the injured neurons. Objectives The structure of random nanofibers is similar to the anisotropic topography of white matter neurite, and can trigger neurite outgrowth at the site of injury. Regeneration process can be accelerated by incorporation of bioactive molecules into fibers. Triiodothyronine (T3) is a vital molecule in brain development and maturation. It also promotes axonal regeneration and remyelination. Results In this study, bioactive nanofibrous scaffold with a controlled release of T3 was fabricated. The controlled release of T3 was achieved by using T3-loaded chitosan nanoparticles incorporated in polycaprolactone (PCL) nanofibers. The biocompatibility of the scaffold was improved by gelatin nanofibers. Co-electrospinning technique was employed to fabricate PCL/Gelatin nanofiber scaffold. Scaffold containing 1%, 2%, and 3% (w/v) of T3-loaded chitosan nanoparticles were synthesized and named PG1, PG2, and PG3, respectively. The release profile of T3 from these three scaffolds showed controlled release for 14 days. The average size of PCL nanofibers were in range of 700-800 nm, and the average size of gelatin nanofibers was 360 nm. Conclusion MTT assay results revealed that the highest proliferation rate of bone marrow-derived mesenchymal stem cells cultured on the fabricated scaffoldswas observed in PG2 scaffold.

Keywords:

Triiodothyronine , Spinal cord injury , Polycaprolactone nanofiber , Gelatin nanofiber , Controlled release , Chitosan nanoparticle