Browsing by Author "Bartolomeu, Maria"
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- Antimicrobial properties and bioactivity potential of smart nanoparticles for dental applicationsPublication . Correia, Bruna L.; Malekshiri, Moslem; Bartolomeu, Maria; Silva, Virgília; Oliveira, Ana; Noites, Rita; Cardoso, Miguel; Mendes, Karina; Gomes, Ana T. P. C.; Duarte, Ana Sofia
- 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.
- Deep Eutectic Solvents as alternative solvents in Antimicrobial Photodynamic TherapyPublication . Vieira, Cátia; Bartolomeu, Maria; Pedro, Sónia N.; Gomes, Ana T. P. C.; Dias, Cristina J.; Gamelas, Sara R. D.; Lourenço, Leandro M. O.; Freire, Carmen S. R.; Neves, M. Graça P. M. S.; Faustino, M. Amparo F.; Almeida, Adelaide
- Degree of contamination of gutta-percha points by Staphylococcus aureus (MRSA/MSSA) strainsPublication . Teles, Ana Moura; Pina, Cristina; Cardoso, Inês Lopes; Tramontana, Antea; Cardoso, Miguel; Duarte, Ana Sofia; Bartolomeu, Maria; Noites, RitaMethicillin-resistant Staphylococcus aureus (MRSA) is considered one of the most harmful bacteria to human health. Dentistry, like all healthcare disciplines, places great emphasis on preventing scenarios that may result in cross-infection. Although various tested and already used materials are suitable for filling the root canal system, Gutta-Percha (GP) remains the preferred and widely accepted gold standard. Objective: We performed an in vitro analysis of the contamination of GP points, regarding the strains of Methicillin-resistant (MRSA) and Methicillin-sensitive (MSSA) Staphylococcus aureus, using classical microbiology methods and molecular biology techniques. Methods: Gutta-Percha points of two different brands from opened packages (already in use for 1 month) were collected for analysis. The assessment involved incubating the GP points in Brain Heart Infusion (BHI) medium to detect microbial growth. Growing microorganisms were plated on a selective and differential chromogenic medium for MRSA/MSSA strains, and the identification of isolates was confirmed by Polymerase Chain Reaction (PCR). In the case of microbial growth, the GP point was submitted to a disinfection protocol. Results: From the 315 collected GP points, only 6 (1.9%) resulted in being positive for microbial growth. After confirmation by PCR, only one sample of the six GP points was contaminated by MRSA, and the remaining five were MSSA-contaminated. The disinfection protocol was effective in all contaminated GP points. Conclusions: The Gutta-Percha points from opened pre-sterilized packages showed a very low degree of contamination by MRSA/MSSA. However, the detection of MSSA and MRSA strains raises concerns about potential contamination in dental clinic environments, and this risk cannot be considered negligible.
- Disinfection of wastewater in the mitigation of SARS-CoV-2 by photodynamic treatmentPublication . Almeida, Adelaide; Gomes, Marta; Bartolomeu, Maria; Vieira, Cátia; Gomes, Ana T. P. C.; Faustino, M. Amparo F.; Neves, M. Graça P. M. S.
- Enhancing bacterial photodynamic inactivation through combined action of potassium iodide and cationic phthalocyaninesPublication . Gamelas, Sara R. D.; Bartolomeu, Maria; Vieira, Cátia; Faustino, Maria A. F.; Tomé, João P. C.; Tomé, Augusto C.; Almeida, Adelaide; Lourenço, Leandro M. O.Infectious diseases remain a leading cause of death all around the world. Over the last three decades, the alarming and escalating emergence of antibiotic-resistant bacterial strains has caused some concern among the scientific community [1,2]. Photodynamic inactivation (PDI) emerges as an alternative for inactivating microorganisms, including bacteria [1–3]. The use of phthalocyanine (Pc) derivatives as photosensitizers (PS) in PDI has already proven effectiveness against various microorganisms [4]. Moreover, the addition of KI as a coadjutant can, in certain circumstances, enhance the efficiency of neutral, negative, and positively charged PS against Gram-negative and Gram-positive bacteria [2,4]. In this study will be demonstrated the effect of KI in PDI of E. coli and S. aureus with cationic Pcs bearing tris(trimethylammoniummethyl) or pyridinium-pyrazolyl groups.
- Factors associated with the prevalence of apical periodontitis: an observational studyPublication . Noites, Rita; Bartolomeu, Maria; Duarte, Ana Sofia; Perez, Alejandro; Cardoso, MiguelObjectives: Apical periodontitis is a lesion of endodontic origin caused by an immune response to necrotic and infected dental pulp. Since apical periodontitis can persist after endodontic treatment, radiographic diagnosis is crucial. This study evaluates factors associated with the prevalence of apical periodontitis in a Portuguese population using the full-scale periapical index. Methods: A cross-sectional study analyzed 402 medical records and panoramic radiographs from January to May 2023. The periapical status, presence of apical periodontitis, quality of endodontic treatment, quality of coronal restoration, presence of caries lesions, and presence of retained root fragments were assessed. The correlation between these variables was examined. Results: Among 9056 teeth, 4.7% presented apical periodontitis (periapical index ≥3), and 53.3% of participants had fewer than one apical periodontitis lesion. Of 437 teeth with endodontic treatment, 300 (69.6%) did not have apical periodontitis, while 131 (30.4%) had apical periodontitis. A significant statistical relationship (p<0.05) was observed between apical periodontitis and other dental conditions, including the presence of retained root fragments, caries lesions, the quality of endodontic treatment, and the quality of restoration. The strongest correlation was found between apical periodontitis and the quality of endodontic treatment (Cramer’s V = 61%), while no consistent correlations were observed with other variables. Conclusions: The prevalence of apical periodontitis was higher in teeth with endodontic treatment, with a strong correlation with treatment quality. The presence of caries lesions, coronal restorations, and retained root fragments also influenced the occurrence of apical periodontitis, reinforcing the need for further studies.
- The impact of metal ions on the photo-antibacterial efficiency of metalloporphyrins with triphenylphosphonium unitsPublication . Chaves, Inês; Morais, Filipe F. M.; Vieira, Cátia; Bartolomeu, Maria; Gomes, Ana T. P. C.; Faustino, M. Amparo F.; Neves, M. Graça P. M. S.; Almeida, Adelaide; Moura, Nuno M. M.The influence of metal ions on the photochemical, photophysical, and antibacterial properties of three cationic porphyrin-triphenylphosphonium conjugates was investigated for the first time. Coordination with Zn(II), Pd(II) and Co(II) enabled fine-tuning of these conjugates properties, with Zn(II) complexes demonstrating particular promise. While Pd(II) and Co(II) complexes failed to generate singlet oxygen (1O2), thereby reducing their efficacy in bacteria photoinactivation, Zn(II) complexes exhibited efficient 1O2 generation and strong bacterial adhesion. Among these, the Zn(II) metalloporphyrin 2-Zn, featuring a well-optimized structure with three triphenylphosphonium units and six positive charges, showed exceptional effectiveness against Gram-negative Escherichia coli at lower concentrations. It significantly outperformed its free-base counterpart, reducing the required irradiation time by more than 65 %. Furthermore, 2-Zn demonstrates to be safe, exhibiting no cytotoxicity towards Vero cells. These findings highlight the potential of Zn(II) porphyrin-triphenylphosphonium complexes as efficient photosensitizers for antimicrobial photodynamic therapy (aPDT), offering a promising approach to address the growing challenge of antibiotic bacterial resistance in both clinical and environmental contexts.
- Insight into the efficiency of microalgae’ lipidic extracts as photosensitizers for Antimicrobial Photodynamic Therapy against Staphylococcus aureusPublication . Mendonça, Inês; Silva, Daniela; Conde, Tiago; Maurício, Tatiana; Cardoso, Helena; Pereira, Hugo; Bartolomeu, Maria; Vieira, Cátia; Domingues, M. Rosário; Almeida, AdelaideAntibacterial resistance causes around 1.27 million deaths annually around the globe and has been recognized as a top 3 priority health threat. Antimicrobial photodynamic therapy (aPDT) is considered a promising alternative to conventional antibiotic treatments. Algal lipid extracts have shown antibacterial effects when used as photosensitizers (PSs) in aPDT. In this work we assessed the photodynamic efficiency of lipidic extracts of microalgae belonging to different phyla (Bacillariophyta, Chlorophyta, Cyanobacteria, Haptophyta, Ochrophyta and Rhodophyta). All the extracts (at 1 mg mL−1) demonstrated a reduction of Staphylococcus aureus >3 log10 (CFU mL−1), exhibiting bactericidal activity. Bacillariophyta and Haptophyta extracts were the top-performing phyla against S. aureus, achieving a reduction >6 log10 (CFU mL−1) with light doses of 60 J cm−2 (Bacillariophyta) and 90 J cm−2 (Haptophyta). The photodynamic properties of the Bacillariophyta Phaeodactylum tricornutum and the Haptophyta Tisochrysis lutea, the best effective microalgae lipid extracts, were also assessed at lower concentrations (75 μg mL−1, 7.5 μg mL−1, and 3.75 μg mL−1), reaching, in general, inactivation rates higher than those obtained with the widely used PSs, such as Methylene Blue and Chlorine e6, at lower concentration and light dose. The presence of chlorophyll c, which can absorb a greater amount of energy than chlorophylls a and b; rich content of polyunsaturated fatty acids (PUFAs) and fucoxanthin, which can also produce ROS, e.g. singlet oxygen (1O2), when photo-energized; a lack of photoprotective carotenoids such as β-carotene, and low content of tocopherol, were associated with the algal extracts with higher antimicrobial activity against S. aureus. The bactericidal activity exhibited by the extracts seems to result from the photooxidation of microalgae PUFAs by the 1O2 and/or other ROS produced by irradiated chlorophylls/carotenoids, which eventually led to bacterial lipid peroxidation and cell death, but further studies are needed to confirm this hypothesis. These results revealed the potential of an unexplored source of natural photosensitizers (microalgae lipid extracts) that can be used as PSs in aPDT as an alternative to conventional antibiotic treatments, and even to conventional PSs, to combat antibacterial resistance.
- Investigation of the potential of deep eutectic solvents (DES) as alternative solvents in antimicrobial photodynamic therapyPublication . Vieira, Cátia; Bartolomeu, Maria; Pedro, Sónia N.; Gomes, Ana T. P. C.; Dias, Cristina J.; Gamelas, Sara R. D.; Lourenço, Leandro M. O.; Freire, Carmen S. R.; Neves, M. Graça P. M. S.; Faustino, M. Amparo F.; Almeida, AdelaideAntimicrobial Photodynamic Therapy (aPDT) is gaining recognition as an effective approach for the photoinactivation of a broad spectrum of microorganisms [1,2]. Due to their apolar behavior, photosensitizers (PS) often have low solubility in aqueous media requiring the use of toxic organic solvents that are incompatible with their application in the field [4]. In this study, the potential of Deep Eutectic Solvents (DES) to prepare formulations of one chlorin (bearing five cationic charges) and two porphyrins (neutral THPP, and tetra cationic Tetra-Py(+)-Me) poorly water-soluble was investigated. To this purpose, formulations of each PS were prepared in DMSO and three DES (betaine:glycerol, proline:xylitol and betaine:citric acid) and their physio-chemical properties, cytotoxicity for mammalian cells, and photodynamic action towards Escherichia coli, as a gramnegative bacterium model, were evaluated. The physico-chemical experiments revealed that all PS were soluble in the selected DES. However, PS stability varied highly depending on the solvent used. In dark conditions, chlorin remained stable in DES formulations while strong aggregation was observed in DMSO. In contrast, THPP showed better stability in the former solvent. Tetra-cationic porphyrin was stable in the dark regardless of the solvent used, but upon irradiation, DES formulations increased this PS photostability. Regarding the biological experiments, betaine:glycerol and proline:xylitol formulations lacked toxicity towards mammalian cells and improved Tetra-Py(+)Me photodynamic activity against E. coli. On the other hand, betaine:citric acid formulation, although highly toxic to Vero cells, enhanced the photodynamic action of both THPP and Tetra-Py(+)-Me. Overall, these findings indicate that DES have a high potential to prepare formulations of PS with low solubility in aqueous solutions and, in some cases, can improve their antimicrobial photodynamic activity.