One of the greatest problems in public health is the continued growing emergence of conventional antibiotic-therapy resistance. Our research group is focused in the synthesis and characterization of new antimicrobial nanomaterials as metallic nanoparticles and antifouling coating.
In this work we have demonstrated the reduction in biofilm growth. The strains used were of relevant clinical pathogens (as Pseudomonas aeruginosa and Staphylococcus aureus). They were treated with Photodynamic Antimicrobial Therapy (PACT) using low concentrations of amoxicillin-coated gold nanoparticles (amoxi@AuNP) as a photosensitizer . The viability reduction of 60% in S. aureus biofilms and 70% in P. aeruginosa biofilms were obtained after three hours of irradiation with white light and amoxi@AuNP. Scanning electron microscopy analysis revealed that amoxi@AuNP could penetrate and cause damage to the biofilm matrix, and interact with bacteria cells. A strong biofilm production in P. aeruginosa was observed by confocal laser scanning microscopy using acridine orange as a probe, and a markedly significant decrease in live bacteria was appreciated when PACT was applied . In conclusion, the use of amoxi@AuNP for PACT allows the viability reduction with high potential in the inhibition of clinical Gram-positive and Gram-negative biofilms. This novel strategy needs shorter irradiation times and lower concentrations of nanoparticles than other reports described. This could be attributed to two major innovations: the selectivity of the nanomaterial for the bacterial wall given by the amoxicillin, and the polydispersity of size and shapes, which seems to contribute to the photo-antibacterial capacity.
María Cecilia Becerra, Ph D, born in Córdoba, Argentina, graduated in Biochemistry in 1997 at Facultad de
Ciencias Químicas, Universidad Nacional de Córdoba. She specialized in Bacteriology and did the PhD studies at Departamento de Ciencias Farmacéuticas, at the same Faculty. She did postdoctoral studies in the topic of new drugs for Chagas disease treatment. Since 2007, is a research member of Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina (CONICET) and since 2015 is Professor of Pharmaceutical Microbiology and Director of the Sterilization Career at FCQ, UNC.
The interest of her research group is focused on the study of the antimicrobial mechanisms related to oxidative stress and nanomaterials with potential application for Photodynamic Antimicrobial Therapy (PACT).