INFIQC   05475
INSTITUTO DE INVESTIGACIONES EN FISICO- QUIMICA DE CORDOBA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Photoactivated nanoparticles kill pathogenic bacteria but proved to be harmless to eukaryotic cells
Autor/es:
MARTINEZ SR; SILVERO MJ; PAVANI C; ARGUELLO G; BECERRA M C; SCAIANO JC; BAPTISTA M
Lugar:
Maresias
Reunión:
Congreso; XII Encontro Latino Americano de Fotoquímica e Fotobiologia; 2015
Institución organizadora:
Sociedad de Fotobiología
Resumen:
PHOTOACTIVATED NANOPARTICLES KILL PATHOGENIC BACTERIA BUT PROVED TO BE HARMLESS TO EUKARYOTIC CELLS Martinez, Sol R3; Silvero, M Jazmin1; Pavani, Christiane4; Argüello, Gerardo A1; Becerra, M Cecilia3; Scaiano, Juan Carlos2 and Baptista, Mauricio4. 1 Instituto de Investigaciones en Físico Química de Córdoba (INFIQC) CONICET-UNC, Departamento de Físico Química. Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba Argentina. 2 Department of Chemistry and Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada 3 Instituto Multidisciplinario de Biología Vegetal (IMBIV), CONICET and Dpto. de Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba. Ciudad Universitaria, X5000HUA Córdoba, Argentina. 4 Instituto de Química, Universidade de São Paulo, São Paulo, Brasil. When a metal nanoparticle interacts with light, having a wavelength longer than the dimensions of the particle itself, Surface Plasmon Resonance (SPR) takes place. In case of gold, SPR absorptions occur in the visible range; this allows us to use cheap LEDs (525nm) as radiation source. The nanomaterial employed here was synthesized according to the procedure published previously (JACS REF2014). It consists of a gold core, encapsulated in a silver shell and stabilized with a dipeptide, specifically aspartame (Asp). The gold core is designed for efficient heat delivery through established plasmonic mechanisms. The silver shell retains the antibacterial properties that are now well characterized in the case of AgNP. The surface protection with aspartame (Asp) leads to excellent aqueous stabilization with long shelf life. Further, aspartame is non-toxic, remarkably inexpensive and easy to replace by another molecule of interest. Previous results showed that bactericidal activity was achieved after only 6h of low energy irradiation in samples treated with Asp@Ag@AuNPs. This could be attributed to the synergism between the silver shell and the plasmon excitation of gold core. In this work, ROS production is detected by Fluorescence Microscopy in Staphylococcus aureus ATCC 29213 and an extended-spectrum beta-lactamases-producing Escherichia coli treated with Asp@Ag@AuNPs and irradiated at 525 nm; while eukaryotic toxicity was evaluated with the MTT essay in fibroblast Balb/3T3 clone A31 (ATCC CCL-163) culture also under irradiation Maximum ROS production was detected in S. aureus and E. coli after 2 and 3 hours of irradiation correspondingly, suggesting that oxidative stress would be the major cause of bacteria death. Cell survival percent was up to 98% even after 18 hours of irradiation using the same LED panel and nanoparticles concentration. The photoactivated nanoparticles have proven to be able to kill completely the bacteria population and still remain harmless for eukaryotic cells under the same conditions. Further investigation will include a co-culture experiment to confirm these results. KEYWORDS: nanoparticles, plasmon, bacteria, reactive oxygen species