Pluripotent Stem Cells: Cancer Study, Therapy, and Vaccination.

INTRODUCTION: Pluripotent stem cells (PSCs) are promising tools for modern regenerative medicine applications because of their stemness properties, which include unlimited self-renewal and the ability to differentiate into all cell types in the body. Evidence suggests that a rare population of cells within a tumor, termed cancer stem cells (CSCs), exhibit stemness and phenotypic plasticity properties that are primarily responsible for resistance to chemotherapy, radiotherapy, metastasis, cancer development, and tumor relapse. Different therapeutic approaches that target CSCs have been developed for tumor eradication. RESULTS AND DISCUSSION: In this review, we first provide an overview of different viewpoints about the origin of CSCs. Particular attention has been paid to views believe that CSCs are probably appeared through dysregulation of very small embryonic-like stem cells (VSELs) which reside in various tissues as the main candidate for tissue-specific stem cells. The expression of pluripotency markers in these two types of cells can strengthen the validity of this theory. In this regard, we discuss the common properties of CSCs and PSCs, and highlight the potential of PSCs in cancer studies, therapeutic applications, as well as educating the immune system against CSCs. CONCLUSION: In conclusion, the resemblance of CSCs to PSCs can provide an appropriate source of CSC-specific antigens through cultivation of PSCs which brings to light promising ideas for prophylactic and therapeutic cancer vaccine development.

Selective Colorimetric Detection of Mn2+ and Cr2+ Ions using Silver Nanoparticles Modified with Sodium Dodecyl Sulfonate and ß-Cyclodextrin.

The present study was conducted to determine manganese (Mn2+) and chromium (Cr2+) ions in aqueous systems with a simple, rapid, sensitive, selective, and cost-effective colorimetric approach. Sodium dodecyl sulfonate (SDS) and ß-cyclodextrin (CD) were used as both stabilizer and surface functionalizing agents for the synthesis of silver nanoparticles (AgNPs). Synthesized AgNPs were characterized by FT-IR spectroscopy, UV-visible spectroscopy, scanning electron microscopy (SEM), and dynamic light scattering (DLS) techniques. The effect of pH on the stability of nanoparticles was investigated. SDS modified silver nanoparticles (SDS-AgNPs) and SDS with ß-cyclodextrin modified silver nanoparticles (SDS-CD-AgNPs) demonstrated sensitive and selective colorimetric detection of Mn2+ and Cr2+ ions at ppm level, respectively. The prepared SDS-AgNPs and SDS-CD-AgNPs solution showed a color change visible to the naked eye from yellow to orange upon adding Mn2+ and Cr2+ ions, respectively; however, other metal ions did not induce such a change. In addition, the results of SEM and DLS for both sensors showed the aggregation of nanoparticles after adding Mn2+ or Cr2+. Overall, the results of this study show the successful synthesis of AgNPs, SDS-AgNPs, and SDS-CD-AgNPs as simple, rapid, sensitive, selective colorimetric sensors with high potential for rapid and on-site detection of Mn2+ and Cr2+ ions.

Fabrication of Silver-Modified Halloysite Nanotubes and their Catalytic Performance in Rhodamine 6G and Methyl Orange Reduction.

Halloysite nanotube supported Ag nanoparticles (Ag/HNT) as catalyst for reduction of Rhodamine 6G (Rh6G) and Methyl orange (MO) have been synthesized and tested. 3-glycidyloxyproyltrimethoxysilane and Triethylene tetramine were successfully utilized to modify the HNTs surface, then Ag+ ions were reduced to AgNPs on this functionalized HNT surface. The structure of AgNPs-impregnated HNT wall was characterized by FTIR, XRD, TEM, FE-SEM and EDX showing the AgNPs to be 10-15 nm in size. The catalytic activity of Ag/HNTs for Rh6G and MO reduction was investigated by UV-vis spectroscopy so as catalyzed and uncatalyzed reaction rate constants could be compared. The rate constant (k) of Rh6G and MO reduction was calculated for catalyzed reactions as 0.224 min-1 and 0.222 min-1, and for un-catalyzed reactions as 0.049 min-1 and 0.014 min-1, respectively. The Ag/HNT catalyzer was effectively recycled six times without appreciable loss of activity. Results indicate that supporting AgNPs on HNT surface functionalized with other compounds with superior performance in reducing Rh6G and MO dyes exist.