Browsing by Author "Bejarano, Julian"

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    Antibacterial Silver Nanoparticles Supported on Graphene Oxide with Reduced Cytotoxicity
    (2019) Angulo-Pineda, Carolina; Palma, Patricia; Bejarano, Julian; Riveros, Ana; Kogan, Marcelo; Palza, Humberto
    The effect of graphene oxide (GO) on both the antibacterial and cytotoxicity behavior of silver nanoparticles (Ag NPs) has been studied. Ag NPs supported on GO were synthesized by two methods, ex situ and in situ. These nanocomposites were characterized by transmission electron microscopy, ultraviolet-visible spectroscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. The antibacterial activity of the nanomaterials was evaluated against Escherichia coli and Staphylococcus aureus by the disk-diffusion method and dynamic contact assays. While GO flakes showed antibacterial behavior only in the dynamic contact test, both GO-Ag NPs nanohybrids eradicated bacteria independent of the condition. Noteworthily, the high cytotoxicity of Ag NPs to human-derived cells was dramatically decreased by the GO layers in the nanocomposite. The in situ hybrid particles showed the lowest cytotoxicity without losing the strong antibacterial effect. These results demonstrate that growth of Ag NPs on GO layers could enable the development of a new family of antibacterial materials with low cytotoxicity to human cells.
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    Light-induced release of the cardioprotective peptide angiotensin-(1-9) from thermosensitive liposomes with gold nanoclusters
    (2020) Bejarano, Julian; Rojas, Aldo; Ramirez Sagredo, Andrea; Riveros, Ana L.; Morales Zavala, Francisco; Flores, Yvo; Riquelme, Jaime A.; Guzman, Fanny; Araya, Eyleen; Chiong, Mario; Ocaranza, María Paz; Morales, Javier O.; Villamizar Sarmiento, Maria Gabriela; Sanchez, Gina; Lavandero, Sergio; Kogan, Marcelo J.
    Angiotensin-(1-9), a component of the non-canonical renin-angiotensin system, has a short half-life in blood. This peptide has shown to prevent and/or attenuate hypertension and cardiovascular remodeling. A controlled release of angiotensin-(1-9) is needed for its delivery to the heart. Our aim was to develop a drug delivery system for angiotensin-(1-9). Thermosensitive liposomes (LipoTherm) were prepared with gold nanoclusters (LipoThermAuNC) to increase the stability and reach a temporal and spatial control of angiotensin-(1-9) release. Encapsulation efficiencies of nearly 50% were achieved in LipoTherm, reaching a total angiotensin-(1-9) loading of around 180 mu M. This angiotensin-(1-9)-loaded LipoTherm sized around 100 nm and exhibited a phase transition temperature of 43.C. AuNC were grown on LipoTherm and the new hybrid nanosystem showed energy absorption in the near-infrared (NIR) wavelength range. By NIR laser irradiation, a controlled release of angiotensin-(1-9) was achieved from the LipoTherm-AuNC nanosystem. These nanosystems did not show any cytotoxic effect on cultured cardiomyocytes. Biological activity of angiotensin-(1-9) released from the LipoTherm-AuNCbased nanosystem was confirmed using an ex vivo Langendorff heart model.
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    Nanoparticles for diagnosis and therapy of atherosclerosis and myocardial infarction : evolution toward prospective theranostic approaches
    (2018) Bejarano, Julian; Navarro-Marquez, Mario; Morales-Zavala, Francisco; Morales, Javier O.; Garcia-Carvajal, Ivonne; Araya-Fuentes, Eyleen; Flores, Yvo; Verdejo Pinochet, Hugo; Castro Gálvez, Pablo Federico; Lavandero, Sergio; Kogan, Marcelo J.