Compatibility of olfactory ensheathing cells with functionalized self-assembling peptide scaffold in vitro

Olfactory ensheathing cell (OEC) transplantation is a promising or potential therapy for spinal cord injury (SCI). However, the effects of injecting OECs directly into SCI site have been limited and unsatisfied due to the complexity of SCI. To improve the outcome, proper biomaterials are thought to be helpful since these materials would allow the cells to grow three-dimensionally and guide cell migration.

In this study, we made a new peptide hydrogel scaffold named GRGDSPmx by mixing the pure RADA16 and designer peptide RADA16-GRGDSP solution, and we examined the molecular integration of the mixed nanofiber scaffolds using atomic force microscopy. In addition, we have studied the behavior of OECs in GRGDSPmx condition as well as on RADA16 scaffold by analyzing their phenotypes including cell proliferation, apoptosis, survival, and morphology.

The experimental results showed that GRGDSPmx could be self-assembled to form a hydrogel. Inverted optical microscopic and scanning electron microscopic analyses showed that OECs are viable and they proliferate within the nanostructured environment of the scaffold. Thiazolyl blue (MTT) assay demonstrated that OEC proliferation rate was increased on GRGDSPmx scaffold compared with the pure RADA16 scaffold. In addition, OECs on GRGDSPmx scaffolds also showed less apoptosis and maintained the original spindle-shaped morphology. Calcein-AM/PI fluorescence staining revealed that OECs cultured on GRGDSPmx grew well and the viable cell count was 95%.

These results suggested that this new hydrogel scaffold provided an ideal substrate for OEC three-dimensional culture and suggested its further application for SCI repair.