Navegando por Autor "Azevedo, Maria Clara Barbosa Silva de"

Agora exibindo 1 - 3 de 3
  • Imagem de Miniatura
    Item
    Curcumin-loaded bovine serum albumin (BSA) nanoparticles: photoreactivity and photodynamic action against Acinetobacter baumannii and Staphylococcus aureus
    (Royal Society of Chemistry) Pinto, Juliana Guerra; Laneri, Francesca; Brambilla, Isabelle de Paula Ribeiro; Azevedo, Maria Clara Barbosa Silva de; Ambrósio, Jéssica Aparecida Ribeiro; Simioni, Andreza Ribeiro; Fraix, Aurore; Sortino, Salvatore; Ferreira-Strixino, Juliana
    Curcumin (CUR) is a naturally occurring pigment, poorly soluble in water and an object of intense interest due to its multifaceted therapeutic and phototherapeutic activity. In this contribution, bovine serum albumin nanoparticles (BSA-NPs) with oppositely charged surfaces have been used as suitable nanocarriers both to overcome the poor water solubility of CUR and to encourage its interaction with Gram-positive and Gram-negative bacteria. The different surface charges of the BSA-NPs do not affect either the spectroscopic or the photochemical behaviour of the encapsulated CUR which in all cases is almost exclusively present in a diketo form rather than the enolic one. This strictly dictates the response of CUR to blue light excitation which, under these conditions, exhibits the usual reactivity of carbonyl compounds toward molecules that behave as hydrogen donors such as the BSA-NP components. Steady-state and time-resolved photochemical experiments show that the encapsulated CUR under- goes photodecomposition with rate basically independent of the presence of oxygen. The photo- decomposition seems to be mediated mainly by an intermolecular H-abstraction from the components of the nanocarrier by the lowest excited triplet state of CUR with the formation of the corresponding ketyl radical occurring in less than 0.5 ms. This radical is oxidized by molecular oxygen, likely leading to peroxyl and hydroperoxyl radical species, probably responsible for the photodynamic action. Accordingly, with the short triplet lifetime, no singlet oxygen photogeneration is observed. Concentrations of 0.2, 0.3 and 0.4 mM were selected for in vitro tests. Internalization of both formulations was observed in strains of A. baumannii and S. aureus, after 15 minutes of interaction. After irradiation, a reduction in the viability of bacteria was observed, at the different concentrations tested, with concentrations of 0.4 and 0.3 mM being the most efficient.
  • Imagem de Miniatura
    Item
    Photodynamic therapy in the treatment of cutaneous habronemosis in a horse: Case report
    (Elsevier) Ferreira, Isabelle; Pinto, Juliana Guerra; Oliveira, Eloíse Gwyneth Lopes; Azevedo, Maria Clara Barbosa Silva de; Marcolino, Luciana Maria Cortez; Ferreira-Strixino, Juliana
    Habronema muscae is a parasitic nematode that causes habronemiasis in horses, leading to chronic skin lesions. The parasite is transmitted via flies, and larvae deposited in wounds result in difficult-to-heal “summer sores”. This case study involved treating a 9-year-old gelding male horse with recurrent habronemiasis using photo- dynamic therapy (PDT) concurrent with conventional treatments. The horse presented with ulcerated, exudative wounds on its limbs and face, unresponsive to traditional treatments. PDT was applied over six months, using methylene blue (MB) as a photosensitizer, combined with LED irradiation. Additionally, an ivermectin-based ointment and other healing agents were used. The results showed a reduction in lesion size after two months, complete healing of the thoracic wounds by month four, and facial wound healing after six months. In this case, PDT was an effective adjunct treatment for managing habronemiasis.
  • Imagem de Miniatura
    Item
    Terapia fotodinâmica com curcumina nanoencapsulada como fotossensibilizador associada à tetraciclina na inativação do biofilme de staphylococcus aureus resistente à meticilina : estudo in vitro
    (2025-07-29) Ferreira, Juliana; Soares, Cristina Pacheco; Arisawa, Emília Angela Loschiavo; Junqueira, Juliana Campos; Azevedo, Maria Clara Barbosa Silva de; Pinto, Juliana Guerra; São José dos Campos
    Staphylococcus aureus resistente à meticilina (MRSA) é uma bactéria Gram-positiva que constitui um dos maiores desafios para a saúde pública global, sendo sua sobrevivência potencialmente aumentada pela formação de biofilme. Isso evidencia a urgência no desenvolvimento de novas abordagens terapêuticas, como a Terapia Fotodinâmica (TFD). O objetivo do trabalho foi analisar o efeito antimicrobiano da TFD usando a curcumina nanoencapsulada em albumina sérica bovina (BSA), podendo estar associada à tetraciclina, em biofilme de MRSA. A NanoBSA nas formas catiônica e aniônica, foi avaliada nas concentrações de 3,0, 2,0 e 1,0 x 10?6 mol.L?¹, assim como sua associação com tetraciclina (30 µg.mL?¹). A irradiação foi realizada com luz LED azul (450 nm, 93,9 mW/cm², 50 J/cm², 532 segundos). A atividade metabólica foi significativamente reduzida tanto na TFD com antibióticos (ATB) quanto sem antibióticos, contudo, no ensaio de contagem de unidades formadoras de colônias, apenas os grupos tratados com TFD associada à tetraciclina apresentaram inibição do crescimento bacteriano. A concentração de 2,0 x 10?6 mol.L?¹ se destacou como a mais eficaz. A combinação de TFD com antibioticoterapia apresenta potencial terapêutico promissor no tratamento de infecções causadas por S. aureus resistente à meticilina.