Fabrication and evaluation of porous and conductive nanofibrous scaffolds for nerve tissue engineering

Abstract

Peripheral nerve repair is still one of the major clinical challenges which has received a great deal of attention. Nerve tissue engineering is a novel treatment approach that provides a permissive environment for neural cells to overcome the constraints of repair. Conductivity and interconnected porosity are two required characteristics for a scaffold to be effective in nerve regeneration. In this study, we aimed to fabricate a conductive scaffold with controlled porosity using polycaprolactone (PCL) and chitosan (Chit), FDA approved materials for the use in implantable medical devices. A novel method of using tetrakis (hydroxymethyl) phosphonium chloride (THPC) and formaldehyde was applied for in situ synthesis of gold nanoparticles (AuNPs) on the scaffolds. In order to achieve desirable porosity, different percentage of polyethylene oxide (PEO) was used as sacrificial fiber. Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FE-SEM) results demonstrated the complete removing of PEO from the scaffolds after washing and construction of interconnected porosities, respectively. Elemental and electrical analysis revealed the successful synthesis of AuNPs with uniform distribution and small average diameter on the PCL/Chit scaffold. Contact angle measurements showed the effect of porosity on hydrophilic properties of the scaffolds, where the porosity of 75–80% remarkably improved surface hydrophilicity. Finally, the effect of conductive nanofibrous scaffold on Schwann cells morphology and vaibility was investigated using FE-SEM and MTT assay, respectively. The results showed that these conductive scaffolds had no cytotoxic effect and support the spindle-shaped morphology of cells with elongated process which are typical of Schwann cell cultures.

Formation of PLGA–PEDOT: PSS Conductive Scaffolds by Supercritical Foaming

“…The electrical conductivity properties of the polymer scaffolds were measured by the two-probe method [ 49 ], using a resistance meter (TRMS Fluke 87-V). The samples were cut into 13 mm 2 -sized pieces.…”

Chitosan-Based Biomaterials for Tissue Regeneration

“…The addition of gold nanoparticles and sacrificial fiber (40% of polyethylene oxide) helped to achieve a desirable interconnected porosity, formed a spherical shape of gold nanoparticles with narrow particle size distribution (126 ± 20 nm), and improved surface hydrophilicity (75–80%) of the scaffold. The results of FE-SEM and MTT assay showed that the scaffold had no cytotoxic effect on stem cells and can support spindle-shaped morphology similar to mature Schwann cell cultures with some proliferation of cells [ 149 ]. Another research group demonstrated the fabrication of poly (L-lactic acid) (PLLA)/chitosan-based scaffold by using a liquid–liquid phase separation technique.…”

3D Printing rGO/PCL/Mel Bionic Conduit for Peripheral Nerve Regeneration

“…The resultant 3D rGO/PCL/Mel hybrid conduit exhibits a lightweight density of (144.3 ± 1.27) mg/cm 3 and the highest reported porosity of (98.5 ± 0.24)% (Figure S9), surpassing that of other natural or synthetic conduits (Fig. 3k) [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] . This remarkable achievement is attributed to the precise regulation of the rGO conduit's microstructural features, from the microscale to macroscopic dimension, by controlling the GO ink's owing state and fabrication parameters such as freeze-casting temperature.…”