Background: Nanotechnology is used in stem cell culture as well as in vivo delivery and tracking of stem cells. Graphene oxide (GO) is a carbon based nanomaterial and it has large surface area as well as good biocompatibility and heteroatoms doped GO exploit its properties. Hybrid GO (hGO) nano structures biocompatibility is depends on its size, dose and exposure time as well as in vitro cell models and hence, need thorough cytotoxicity studies in different species in vitro cell models. Methods: Caprine Wharton’s jelly derived mesenchymal stem cells (WJ-MSCs) were isolated, characterized and dose dependent (100, 50, 25, 10 and 0µg /ml) in vitro cytotoxicity of three different hGO nano structures (phosphorus doped graphene oxide titanium oxide tubes, rods and sheets) were analysed in caprine WJ-MSCs by studying cell cytotoxicity assays. Result: All three hGO nano structures were damaged cell morphology at 100 and 50 µg /ml doses, however, morphologically more good cells were observed in hGO tubes treated group than hGO rods and hGO sheets at 25 and 10 µg/ml doses as compared to control. Cell viability percentage was significantly (P less than 0.01) decreased at dose 100 µg/ml and it was significantly (P less than 0.01) increased at 25 µg/ml dose as compared to 50, 10 and 0 µg/ml doses. But, hGO tubes significantly (P less than 0.01) increased cell viability % as compared to hGO rods and hGO sheets. Cell population doubling time (PDT) was not altered significantly by all hGO nano structures, but 100 and 50 µg/ml doses significantly (P less than 0.01)increased cell PDT as compared to 25, 10 and 0 µg/ml doses. All hGO nano structures were non significantly altered growth curve, however, all hGO nano structures at 25 µg /ml dose altered (inclined) shape of growth curve, while 100 and 50 µg /ml doses significantly declined growth curve shape as compared to 10 and 0 µg /ml doses. Cell proliferation % was significantly (P less than 0.01) increased at 25 and 10 µg/ml doses, while, it was significantly (P less than 0.01) decreased at 100 µg /ml dose as compared to 50 and 0 µg /ml. However, there was no significance difference was observed in cell proliferation % in groups treated by different hGO nanostructures. In last, it was concluded as, hGO nano structures cytotoxicity was dose dependent and hGO nano tubes were least cytotoxic in caprine WJ-MSCs.

In present study, caprine Wharton's jelly derived mesenchymal stem cells (WJ-MSCs) were isolated and characterized by osteogenic and adipogenic differentiation. Total 12 hybrid graphene oxide nanocomposites (hGO NCs) such as N2 doped GO-HA NCs, P doped GO-HA NCs, S doped GO-HA NCs, N2 doped GO-SiO2 NCs, P doped GO-SiO2 NCs, S doped GO-SiO2 NCs, N2 doped GO-TiO2 NCs, P doped GO-TiO2 NCs, S doped GO-TiO2 NCs, N2 doped GO-Au NCs, P doped GO-Au NCs and S doped GO-Au NCs were incorporated at doses 100, 50, 25 , 10 and 0 µg/ml in vitrification solution. Caprine WJ-MSCs were cryopreserved by using open pulled straw (OPS) vitrification method and analysed hGO NCs effect on their post thaw viability and culture characteristics. Caprine WJ-MSCs were exhibited normal fibroblastoid morphology and differentiated in to osteogenic and adipogenic lineages. The significant (P<0.01) highest and lowest caprine WJ-MSCs post thaw viability (cumulatively) was observed in P-GO-TiO2 NC and P-GO-HA NC groups, respectively along with all doses (cumulatively) significantly (P<0.01) decreased post thaw cell viability as compared with control. All hGO NCs were significantly (P<0.01) decreased caprine WJ-MSCs post thaw viability at doses 100 and 50 µg/ml as compared to 25, 10 and 0 µg/ml doses. Post thaw caprine WJ-MSCs were grew in normal pattern with similar fibroblast like morphology on days 14. In conclusion, all hGO NCs at doses 50 and 100 µl/ml are cytotoxic and P-GO-TiO2 NC is least decrease caprine WJ-MSCs post thaw viability.

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