Navegando por Autor "Laneri, Francesca"

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    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.
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    N-Doped Carbon Dot-Based Nanoconjugates with Simultaneous Generation of Nitric Oxide and Singlet Oxygen for Phototherapeutic Applications
    (ACS Publications) Laneri, Francesca; Parisi, Cristina; Andrigo, Vittoria; Pinto, Juliana Guerra; Marcolino, Luciana Maria Cortez; Ferreira-Strixino, Juliana; Natile, Marta Maria; Sortino, Salvatore
    Nitric oxide (NO) and singlet oxygen (O2) represent two of the most intriguing agents for unconventional phototherapeutic applications in cancer. In this contribution, N-doped carbon dots (NCDs) with strong absorption in the biocompatible green region have been synthesized and covalently decorated with an otherwise blue-light-activatable NO photodonor (NOPD), leading to a nanoconjugate ca. 3.5 nm in diameter. The NCD core of the nanoconstruct acts as a green light antenna, permitting the release of NO from the NOPD by an intramolecular photoinduced electron transfer, with an improvement of more than 100 nm in the excitation wavelength. Simultaneously, green light excitation generates O2 by collisional energy transfer with molecular oxygen. Due to its emissive properties, the nanoconjugate can be visualized in 9L/LacZ brain cancer cells, where it localizes mainly in the cytoplasm. Amplified mortality of cancer cells is observed upon green light irradiation due to the mutual photodynamic action of NO and O2.