Browsing by Author "Neves, Maria G. P. M. S."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Can corrole dimers be good photosensitizers to kill bacteria?Publication . Lacerda, Paula S. S.; Bartolomeu, Maria; Gomes, Ana T. P. C.; Duarte, Ana S.; Almeida, Adelaide; Faustino, Maria A. F.; Neves, Maria G. P. M. S.; Barata, Joana F. B.Corroles possess key photophysical and photochemical properties to be exploited as thera-peutic agents in antimicrobial photodynamic therapy (aPDT). Herein, we present for the first time the antimicrobial efficiency of three corrole dimers and of the corresponding precursor against the Gram(+) bacterium Staphylococcus aureus. Additionally, to explore future clinical applications, the cytotoxicity of the most promising derivatives towards Vero cells was evaluated. The aPDT assays performed under white light irradiation (50 mW/cm2; light dose 450 J/cm2) and at a corrole concen-tration of 15 µM showed that some dimers were able to reduce 99.9999% of S. aureus strain (decrease of 5 log10 CFU/mL) and their photodynamic efficiency was dependent on position, type of linkage, and aggregation behavior. Under the same light conditions, the corrole precursor 1 demonstrated notable photodynamic efficiency, achieving total photoinactivation (>8.0 log10 CFU/mL reduction) after the same period of irradiation (light dose 450 J/cm2). No cytotoxicity was observed when Vero cells were exposed to corrole 1 and dimer 3 for 24 h according to ISO guidelines (ISO 10993-5) for in vitro cytotoxicity of medical devices. The results show that corrole dimers, dependent on their structures, can be considered good photosensitizers to kill Staphylococcus aureus.
- Graphene oxide and graphene quantum dots as delivery systems of cationic porphyrins: photo-antiproliferative activity evaluation towards T24 human bladder cancer cellsPublication . Menilli, Luca; Monteiro, Ana R.; Lazzarotto, Silvia; Morais, Filipe M. P.; Gomes, Ana T. P. C.; Moura, Nuno M. M.; Fateixa, Sara; Faustino, Maria A. F.; Neves, Maria G. P. M. S.; Trindade, Tito; Miolo, GiorgiaThe development of new photodynamic therapy (PDT) agents designed for bladder cancer (BC) treatments is of utmost importance to prevent its recurrence and progression towards more invasive forms. Here, three different porphyrinic photosensitizers (PS) (TMPyP, Zn-TMPyP, and P1-C5 ) were non-covalently loaded onto graphene oxide (GO) or graphene quantum dots (GQDs) in a one-step process. The cytotoxic effects of the free PS and of the corresponding hybrids were compared upon blue (BL) and red-light (RL) exposure on T24 human BC cells. In addition, intracellular reactive oxygen species (ROS) and singlet oxygen generation were measured. TMPyP and Zn-TMPyP showed higher efficiency under BL (IC50: 0.42 and 0.22 µm, respectively), while P1-C5 was more active under RL (IC50: 0.14 µm). In general, these PS could induce apoptotic cell death through lysosomes damage. The in vitro photosensitizing activity of the PS was not compromised after their immobilization onto graphene-based nanomaterials, with Zn-TMPyP@GQDs being the most promising hybrid system under RL (IC50: 0.37 µg/mL). Overall, our data confirm that GO and GQDs may represent valid platforms for PS delivery, without altering their performance for PDT on BC cells.