Browsing by Author "Torres-Mendieta, R."

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    Ag Nanoparticles/alpha-Ag2WO4 Composite Formed by Electron Beam and Femtosecond Irradiation as Potent Antifungal and Antitumor Agents
    (2019-07-23) Assisi, M.; Robeldo, T.; Foggi, C. C.; Kubo, A. M.; Minguez-Vega, G.; Condoncillo, E.; Beltran-Mir, H.; Torres-Mendieta, R.; Andres, J.; Oliva, M.; Vergani, C. E.; Barbugli, P. A.; Camargo, E. R.; Borra, R. C.; Longo, E.
    The ability to manipulate the structure and function of promising systems via external stimuli is emerging with the development of reconfgurable and programmable multifunctional materials. Increasing antifungal and antitumor activity requires novel, efective treatments to be diligently sought. In this work, the synthesis, characterization, and in vitro biological screening of pure α-Ag2WO4, irradiated with electrons and with non-focused and focused femtosecond laser beams are reported. We demonstrate, for the frst time, that Ag nanoparticles/α-Ag2WO4 composite displays potent antifungal and antitumor activity. This composite had an extreme low inhibition concentration against Candida albicans, cause the modulation of α-Ag2WO4 perform the fungicidal activity more efcient. For tumor activity, it was found that the composite showed a high selectivity against the cancer cells (MB49), thus depleting the populations of cancer cells by necrosis and apoptosis, without the healthy cells (BALB/3T3) being afected.
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    Fluorescence cell imaging using carbon quantum dots generated by continuous fragmentation
    (2019-01-01) Donate-Buendia, C.; Torres-Mendieta, R.; Pyatenko, A.; Falomir, E.; Fernandez-Alonso, M.; Minguez-Vega, G.
    In this contribution, the synthesis of fluorescent carbon quantum dots (CQDs) by laser fragmentation is reported. To achieve it, an initial suspension of carbon glassy microparticles in polyethylene glycol 200 is irradiated using two different experimental setups, a batch and a flow jet configuration. While the batch configuration is the standard irradiation setup, the flow jet configuration is less extended and it is proposed an implementation with common laboratory material. Besides, this system ensures an improved control over the fluence and the energy delivered to the target, increasing CQDs fabrication rate by 15%. The fluorescence of the generated nanoparticles is measured obtaining an increase of the quantum yield of one order of magnitude. The achieved fluorescence together with their easy cell internalization permits their use as fluorophore. To prove it, the flow jet synthesized CQDs are used for fluorescent imaging of healthy and cancerous human cells. The required incubation time is only 10 minutes and no centrifugation or any other extra processing of the sample is needed. In addition, the fluorescence photostability is measured to be of more than 2 hours in an in vitro application, proving the viability of the generated CQDs even for labeling in applications where long image acquisition times are required.