Conclusion
Alginate-based scaffolds have been extensively investigated for NTE,
however, they faced some limitations that hampered their further
developments. Importantly, alginate-based scaffolds have poor mechanical
strength and degradation rate, which are not matched with native tissue
microenvironment. It was found that incorporation of graphene within the
alginate matrix can address these drawbacks. However, it is important to
investigate cellular viability and cytotoxicity of 3D graphene-based
composite scaffold. In addition, it is revealed that coating of
scaffolds induces cell functions, adhesion and growth. Therefore, this
study examined the biodegradation, biocompatibility, bioactivity and
cytotoxicity of neural crest-derived DPSCs loaded graphene-based 3D
composite scaffolds, using three different coating conditions.
It was shown that the composite GOSA and RGOSA scaffolds have controlled
biodegradability which is effective in therapeutic tissue engineering
applications. DPSCs viability cultured onto SA and GOSA scaffolds was
higher than that of on 2D controls thus signifying surface cell adhesion
followed by cell infiltration through the porous matrices. Therefore,
superior proliferative ability of DPSCs can be obtained when cells are
cultured on 3D porous scaffolds. The LDH assay showed comparable DPSCs
toxicity on the GOSA and RGOSA scaffolds to that obtained on a 2D
surface in the absence of the biomaterial, highlighting no significant
cytotoxic effects of graphene incorporation after 2 days of DPSCs
culture. Furthermore, smaller mean pore size of scaffolds resulted in
higher cellular activity and relatively less cytotoxicity, which is due
to more available specific surface area on scaffolds with smaller mean
pore sizes. In terms of coating conditions, PLL was the most robust
reagent that improved cell-matrix adherence and affected metabolism
activity of DPSCs, being superior to combined PLL+LAM coating.
Furthermore, the cytotoxicity of GOSA and RGOSA scaffolds in the
presence of serum is increased compared to serum-free condition,
indicating that DPSCs can be cultured in serum deprivation onto the
fabricated scaffolds for clinical translation. The findings from the
current study suggest that the proposed 3D graphene-based composite
scaffolds had a favourable effect on the biological responses of DPSCs
which could be exploited in further DPSCs differentiation and electrical
stimulation for functional NTE.