Journal: International Journal of Molecular Sciences
Article Title: Polyoxometalate Nanoparticles as a Potential Glioblastoma Therapeutic via Lipid-Mediated Cell Death
doi: 10.3390/ijms23158263
Figure Lengend Snippet: Molybdenum and tungsten containing polyoxometalates are stable in aqueous and buffered solutions. ( A , B ) Molybdenum ((NH 4 )Mo 7 O 24 ) and tungsten (H 3 PW 12 O 40 ) polyoxometalates were prepared (2–100 µM). The relative absorbances were plotted in an XY-plot where the slope represents the molar attenuation coefficient. ( C , D ) A 100 mM (in 0.5 M HEPES) stock solution for each POM on day 1 to test for stability. The stock was diluted to 1 mM in water to also obtain information about the stability of the POMs in aqueous environments. The aqueous solutions were further diluted to approximately 25 mM to be in an appropriate absorbance range (<1 Abs) on day 1 (Prepared). The stability was tracked for 14 days, after which a new dilution was made from the 100 mM stock (Fresh). The Mo-POM ( C ) concentration appears stable in both the 100 mM (in 0.5 M HEPES) solution in a lighted lab environment, as well as in an aqueous solution. After 35 days, a 1 mM solution was made in complete medium, then diluted to 25 mM. The solution was kept in an incubator for 4 days to reflect a maximum treatment time. The Mo-POM was both measurable in medium and stable for at least 4 days. The W-POM ( D ) concentration of the aqueous dilution dropped from ≈23 µM to ≈21 µM in the first few days. Making a fresh dilution (d = 14) shows the same effect. In contrast to the molybdenum POM, the W-POMs appear to be less stable in media over a time of 4 days, whereas the observed concentration dropped from ≈25 µM to ≈15 µM.
Article Snippet: Tungsten POM (phosphotungstic acid hydrate, Sigma-Aldrich); molecular weight = 2880.05 g mol −1 .
Techniques: Concentration Assay
