Palladium Nanoparticles Functionalized with PVP-Quercetin Inhibits Cell Proliferation and Activates Apoptosis in Colorectal Cancer Cells
Hilda Amelia Piñón-Castillo, Rigoberto Martínez-Chamarro, Reyna Reyes‐Martínez, Yarely M. Salinas-Vera, Laura Alicia Manjarrez Nevárez, L. Castellanos, César López‐Camarillo, Erasmo Orrantia‐Borunda
Abstract
Nanotechnology is focused on the development and application of novel nanomaterials with particular physicochemical properties. Palladium nanoparticles (PdNPs) have been used as antimicrobials, antifungals, and photochemicals and for catalytic activity in dye reduction. In the present investigation, we developed and characterized PdNPs as a carrier of quercetin and initiated a study of its effects in colorectal cancer cells. PdNPs were first functionalized with polyvinylpyrrolidone (PVP) and then coupled to quercetin (PdNPs-PVP-Q). Our results showed that quercetin was efficiently incorporated to PdNPs-PVP, as demonstrated using UV/Vis and FT-IR spectroscopy. Using transmission electron microscopy, we demonstrated a reduction in size from 3–14.47 nm of PdNPs alone to 1.8–7.4 nm of PdNPs-PVP and to 2.12–3.14 of PdNPs-PVP-Q, indicating an increase in superficial area in functionalized PdNPs-Q. Moreover, hydrodynamic size studies using dynamic light scattering showed a reduction in size from 2120.33 nm ± 112.53 with PdNPs alone to 129.96 nm ± 6.23 for PdNPs-PVP-Q, suggesting a major reactivity when quercetin is coupled to nanoparticles. X-ray diffraction assays show that the addition of PVP or quercetin to PdNPs does not influence the crystallinity state. Catalytic activity assays of PdNPs-PVP-Q evidenced the chemical reduction of 4-nitrophenol, methyl orange, and methyl blue, thus confirming an electron acceptor capacity of nanoparticles. Finally, biological activity studies using MTT assays showed a significant inhibition (p < 0.05) of cell proliferation of HCT-15 colorectal cancer cells exposed to PdNPs-PVP-Q in comparison to untreated cells. Moreover, treatment with PdNPs-PVP-Q resulted in the apoptosis activation of HCT-15 cells. In conclusion, here we show for the first time the development of PdNPs-PVP-Q and evidence its biological activities through the inhibition of cell proliferation and apoptosis activation in colorectal cancer cells in vitro.