Bailón-Ruiz, Sonia J.

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2006 - 200912010 - 20131
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    Processing of Zn-based quantum dots as potential photo-sensitizers for nanomedicine applications
    (2013) Bailón-Ruiz, Sonia J.; Perales Perez, Oscar; College of Arts and Sciencies - Sciences; Román, Félix R.; Rivera, Nilka; Melendez, Enrique; Department of Chemistry; Fernández, Félix
    Photodynamic therapy (PDT), is a less-traumatic and selective method to destroy cancer cells. In PDT, the light irradiation of fluorescent-photosensitizer agents generate controlled amounts of citotoxic species. Semiconductor quantum dots, (QDs), because of their narrow emission spectra, large quantum yield, chemical stability against photo-bleaching, potential for surface functionalization and efficient energy donors, can be considered promising candidates for PDT. On this basis, our research addresses the systematic evaluation of the microwave-assisted synthesis of Zn-based water-stable QDs to be used as photosensitizers in cancer treatment. Cd-based QDs are also evaluated for comparison purposes. Zn-based QDs (~4nm in diameter) were synthesized in presence of thiols in aqueous phase. UV-Vis spectroscopy and photoluminescence spectroscopy analyses evidenced the achievement of suitable optical properties. X-Ray Diffraction (XRD) and Fourier Transform Infrared (FT-IR) studies confirmed the formation of the desired phases, as well as the actual functionalization of the QDs surface by thiol-groups. The assessment of the cytotoxicity of Zn-based and Cd-based QDs in human pancreatic carcinoma cells (PANC-1) is also reported. The cytotoxicity of synthesized QDs, mainly located in the PANC-1 cytoplasm, was strongly dependent of their composition and concentration. The cytotoxicity of QDs, due to the production of singlet oxygen and reactive oxygen species, was enhanced under UV irradiation as a function of the exposure time.
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    Lead bioaccumulation by three tropical plant species
    (2006) Bailón-Ruiz, Sonia J.; Massol-Deyá, Arturo A.; College of Arts and Sciences - Sciences; Kolterman, Duane A.; Gill, John M.; Department of Biology; Muñoz, Miguel A.
    Previous studies indicate that fast growing plants with high biomass could be employed for the remediation of lead (Pb) contaminated sites. Phytoextraction of Pb in a contaminated substrate was evaluated. To evaluate a possible phytotoxicity; physiological indicators such as chlorophyll content and electrolyte leakage were studied. Also, the growth, tolerance index and translocation index of Cucurbita moschata, Capsicum chinense and Cajanus cajan were evaluated. Finally, the effect of the chelating agent (EDTA) on Pb availability and potential translocation was examined. The metal content in the substrate was analyzed using a Flame Atomic Absorption Spectrophotometer (F-AAS) while the Pb content in vegetal tissues (root, stem, leaf and fruit) was estimated using a Graphite Furnace Atomic Absorption Spectrophotometer (GF-AAS). To the eighth week of exposure, the highest absorption of lead was observed in the treatment of 60 mg/kg of Pb with 200 mg/kg of EDTA. Root tissue samples of C. moschata and C. cajan leaves samples accumulated 24.82 and 28.94 mg of Pb /kg of dry weight, respectively. The chlorophyll content, electrolyte leakage, length of roots and stems, and biomass content were unaffected by the exposure to lead or EDTA.