https://repositorio.ufba.br/handle/ri/43739 2026-04-17T22:44:33Z 2026-04-17T22:44:33Z Araujo, Monique Gonzaga de https://repositorio.ufba.br/handle/ri/44108 2026-02-26T13:01:00Z 2025-12-15T00:00:00Z

Atividade de nanopartículas de prata biogênicas sobre Staphylococcus spp. isolados de animais Araujo, Monique Gonzaga de Portela, Ricardo Wagner Dias The genus Staphylococcus comprises bacteria widely distributed in humans and animals, including species capable of causing opportunistic infections and exhibiting significant resistance to antimicrobial agents. In veterinary settings, these bacteria are particularly relevant due to the close contact between domestic animals and humans, which favors cross transmission and selects for multidrug-resistant strains. In this scenario, there is a growing need to investigate therapeutic alternatives that can overcome the loss of efficacy of conventional antibiotics. Among the most promising strategies are metallic nanoparticles, especially biogenic silver nanoparticles (bioAgNPs), whose synthesis mediated by plant extracts proves to be sustainable and capable of generating stable, reactive particles with recognized antimicrobial potential. Therefore, this study aimed to identify Staphylococcus spp. isolates from animals and to evaluate the antimicrobial and antibiofilm activity of bioAgNPs synthesized from the aqueous extract of Trichilia catigua bark. Initially, microorganisms were isolated and identified by MALDI-TOF MS mass spectrometry. Subsequently, susceptibility testing to commercial antimicrobials was performed using the disk diffusion method. Following this, the antimicrobial activity of the bioAgNPs was investigated by broth microdilution. Finally, the action of the bioAgNPs on the initial formation and mature biofilm of the bacteria was evaluated. The isolates showed a broad spectrum of resistance to conventional antibiotics, with resistance to β lactams being particularly noteworthy. In the microdilution tests, it was observed that all species were inhibited by microconcentrations of bioAgNPs, with MIC₁₀₀ values ranging from 3.37 to 6.74 µg/mL. The MBC₁₀₀ values were equal to or up to twice the MIC values, demonstrating the bactericidal nature of the nanoparticles. BioAgNPs significantly reduced the biomass of initial and mature biofilms, although without promoting complete eradication. Thus, the results demonstrate that bioAgNPs synthesized from T. catigua represent a promising and efficient approach for controlling multidrug-resistant Staphylococcus spp., including emerging species of veterinary relevance and zoonotic potential. Universidade Federal da Bahia Trabalho de Conclusão de Curso

2025-12-15T00:00:00Z Gonçalves, Rebeca César Santos https://repositorio.ufba.br/handle/ri/43838 2026-01-21T19:05:26Z 2025-12-18T00:00:00Z

Planejamento fatorial para obtenção de arranjos de microagulhas por impressão 3D com potencial uso em drug delivery Gonçalves, Rebeca César Santos Santos, Bruno Guimarães da Fonseca dos The present study aimed to develop, characterise, and optimise microneedle (MN) arrays using three-dimensional printing based on liquid crystal display (LCD) technology. MNs represent an alternative, minimally invasive, and painless route for the administration of drugs and nutrients, such as vitamin B12 and insulin, overcoming limitations associated with the oral route, including low bioavailability, as well as those related to conventional injections, such as pain and tissue trauma. The study focused on the geometric optimisation of resin-based master moulds with a hybrid geometry composed of a cubic base and a pyramidal tip, prior to the production of silicone micromoulds intended for the fabrication of polymeric MNs. The adopted methodology was based on an experimental design employing Response Surface Methodology (RSM), considering printing angle and exposure time as independent factors, and MN length, depth, height, and tip definition as response variables. Statistical analysis, performed using analysis of variance and Pareto charts, identified exposure time as the most significant factor, exhibiting a parabolic behaviour across all evaluated responses, with a maximum point occurring prior to overcuring. Although secondary, the printing angle also influenced the responses analysed. Application of the Derringer–Suich desirability function for multi-objective optimisation indicated optimal operating conditions associated with a moderate exposure time and an intermediate printing angle. However, morphological analysis revealed that, due to the low layer thickness adopted (10 micrometres), the MNs exhibited poor geometric fidelity under all studied conditions. It is therefore concluded that the experimental design approach was effective in identifying critical process parameters, while also indicating the need to adjust the layer thickness to values greater than 10 micrometres in future studies in order to improve the geometric accuracy of the microstructures. Universidade Federal da Bahia Trabalho de Conclusão de Curso

2025-12-18T00:00:00Z