ESTeSL - Escola Superior de Tecnologia da Saúde de Lisboa
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Browsing ESTeSL - Escola Superior de Tecnologia da Saúde de Lisboa by advisor "Abreu, Sónia Gonçalves"
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- Towards antimicrobial solutions against human pathogens by exploiting the biotechnological potential of microbial pigmentsPublication . Cardetas, Andreia Isabel Pereira; Viegas, Carla; Castro, Pedro Soares; Abreu, Sónia GonçalvesABSTRACT - The global and urgent need for antimicrobial solutions has led to the prospection of microbial biomolecules as a source of new compounds against pathogens associated with multidrug resistance (e.g., strains of Staphylococcus aureus). The antimicrobial potential of violacein pigment has been widely studied, against bacteria, fungi, and viruses. Moreover, the combination of bioactive pigments with silver star-shaped nanoparticles (AgNSs) has the potential to improve the activity and stability of the nanoparticle-pigment complex, as well as reduce its toxicity/immunogenicity. Consequently, the complex may have a great biotechnological potential as an efficient nano-based antimicrobial agent. This master thesis aimed to characterise the antimicrobial potential of violacein and to synthesise violacein-conjugated silver nanoparticles (AgNSs-Vio). For this purpose, different production conditions were tested and Luria Bertani medium supplemented with 2.5% glycerol was selected as preferred. The extraction of violacein was established with acidified ethanol and the evaluation of antimicrobial activity was tested against Staphylococcus aureus: an antibiotic susceptible strain (SA) and a methicillin-resistant strain (MRSA). It was not possible to determine an exact minimum inhibitory value for the strains tested. However, a decrease in CFU/mL values was observed at concentrations of 80 - 120 µg/mL for both strains, being statistically significant in MRSA. The preliminary antibiofilm test for the two strains showed inhibition of at least 50% when compared to the control. Finally, biochemical, and biophysical techniques were used to establish the production process of AgNSs-Vio and the characterisation of its properties, thus creating background knowledge for the development of an antimicrobial nano-platform.