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Silver nanoparticles (AgNPs) are gaining rapid popularity in many commonly used medical and commercial products for their unique anti-bacterial properties. The molecular mechanisms of effects of AgNPs on stem cell self-renewal and proliferation have not yet been well understood. The aim of the work is to use mouse embryonic stem cells (mESCs) as a cellular model to evaluate the toxicity of AgNPs. mESC is a very special cell type which has self-renewal and differentiation properties. The objective of this project is to determine the effects of AgNPs with different surface chemical compositions on the self-renewal and cell cycle of mESCs. Two different surface chemical compositions of AgNPs, polysaccharide-coated and hydrocarbon-coated, were used to test their toxic effects on self-renewal and proliferation of mESCs. The results indicated that both polysaccharide-coated and hydrocarbon-coated AgNPs changed the cell morphology of mESCs. Cell cycle analysis indicated that AgNPs induced mESCs cell cycle arrest at G1 and S phases through inhibition of the hyperphosphorylation of Retinoblastoma (Rb) protein. Furthermore, AgNPs exposure reduced Oct4A isoform expression which is responsible for the pluripotency of mESCs, and induced the expression of several isoforms OCT4B-265, OCT4B-190, OCT4B-164 which were suggested involved in stem cell stresses responses. In addition, the evidence of reactive oxygen species (ROS) production with two different surface chemical compositions of AgNPs supported our hypothesis that the toxic effect AgNPs exposure is due to overproduction of ROS which altered the gene expression and protein modifications. Polysaccharide coating reduced ROS production, and thus reduced the AgNPs toxicity.

Here, we describe a focused microarray for screening rat embryonic stem cells (ESCs) and provide validation data that this array can distinguish undifferentiated rat ESCs from rat trophoblast stem (TS) cells, rat extraembryonic endoderm cells, mouse embryonic fibroblast feeder cells, and differentiated rat ESCs. Using this tool, genuine rat ESC lines, which have been expanded in a conventional rat ESC medium containing two inhibitors (2i), for example, glycogen synthase kinase 3 (GSK3) and mitogen-activated protein kinase (MEK) inhibitors, and leukemia inhibitory factor, and genuine rat ESCs, which have been expanded in rat ESC medium containing four inhibitors (4i), for example, GSK3, MEK, Alk5, and Rho-associated kinase inhibitors were compared; as were genuine rat ESCs from 4 different strains of rats. Expression of Cdx2, a gene associated with trophoblast determination, was observed in genuine, undifferentiated rat ESCs from 4 strains and from both 2i and 4i ESC derivation medium. This finding is in contrast to undifferentiated mouse ESCs that do not express Cdx2. The rat ESC focused microarray described in this report has utility for rapid screening of rat ESCs. This tool will enable optimization of culture conditions in the future.

The reprogramming of fibroblasts to pluripotent stem cells and the direct conversion of fibroblasts to functional neurons has been successfully manipulated by ectopic expression of defined factors. We demonstrate that mouse fibroblasts can be converted into sphere cells by detaching the fibroblast cells by protease and then using the AlbuMAX I-containing culture medium without genetic alteration. AlbuMAX I is a lipid-rich albumin. Albumin-associated lipids arachidonic acid (AA) and pluronic F-68 were responsible for this effect. The converted colonies were positive for both alkaline phosphatase and surface specific embryonic antigen-1 (SSEA-1) staining. Global gene expression analysis indicated that the sphere cells were in an intermediate state compared with mES cells and MEF cells. The sphere cells were able to differentiate into tissues representing all three embryonic germ layers following retinoic acid treatment, and differentiated into smooth muscle cells following treatment with vascular endothelial growth factor (VEGF). The study presented a potential novel approach to transdifferentiate mouse fibroblast cells into other cell lineages mediated by AlbuMAX I-containing culture medium.

Fabrication of ZnO nanoparticles (NPs) via green process has received enormous attention for its application in biomedicine. Here, a simple and cost-effective green route is reported for the synthesis of ZrO2-doped ZnO/reduced graphene oxide nanocomposites (ZnO/ZrO2/rGO NCs) exploiting ginger rhizome extract. Our aim was to improve the anticancer performance of ZnO/ZrO2/rGO NCs without toxicity to normal cells. The preparation of pure ZnO NPs, ZnO/ZrO2 NCs, and ZnO/ZrO2/rGO NCs was confirmed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), photoluminescence (PL), and dynamic light scattering (DLS). XRD spectra of ZnO/ZrO2/rGO NCs exhibited two distinct sets of diffraction peaks, ZnO wurtzite structure, and ZrO2 phases (monoclinic + tetragonal). The SEM and TEM data show that ZrO2-doped ZnO particles were uniformly distributed on rGO sheets with the excellent quality of lattice fringes without alterations. PL spectra intensity and particle size of ZnO decreased after ZrO2-doping and rGO addition. DLS data demonstrated that green prepared samples show excellent colloidal stability in aqueous suspension. Biological results showed that ZnO/ZrO2/rGO NCs display around 3.5-fold higher anticancer efficacy in human lung cancer (A549) and breast cancer (MCF7) cells than ZnO NPs. A mechanistic approach suggested that the anticancer response of ZnO/ZrO2/rGO NCs was mediated via oxidative stress evident by the induction of the intracellular reactive oxygen species level and the reduction of the glutathione level. Moreover, green prepared nanostructures display good cytocompatibility in normal cell lines; human lung fibroblasts (IMR90) and breast epithelial (MCF10A) cells. However, the cytocompatibility of ZnO/ZrO2/rGO NCs in normal cells was better than those of pure ZnO NPs and ZnO/ZrO2 NCs. Augmented anticancer potential and improved cytocompatibility of ZnO/ZrO2/rGO NCs was due to ginger extract mediated beneficial synergism between ZnO, ZrO2, and rGO. This novel investigation emphasizes the significance of medicinal herb mediated ZnO-based NCs synthesis for biomedical research.