Bioengenharia
URI permanente para esta coleçãohttps://repositorioacademico.universidadebrasil.edu.br/handle/123456789/31
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Resultados da Pesquisa
Item Avaliação da razão dímero/monômero nas formulações comerciais de azul de metileno empregados na terapia fotodinâmica antimicrobiana(Universidade Brasil, 2024) CAMPOS, Rosimari Mariano de; NUNEZ, Silvia CristinaAntimicrobial photodynamic therapy (aPDT) has been extensively studied in dentistry as an effective approach for treating localized infections, including periodontal and endodontic infections. Among the available photosensitizers (PS), methylene blue (MB) stands out as a widely recognized option in scientific literature due to its photodynamic efficiency. This efficiency, however, is directly influenced by the proportion of dimeric and monomeric forms of MB, which are significantly affected by the ionic interactions present in the solution, thereby impacting the PS's performance in photodynamic applications. This study employed spectroscopic methods to evaluate different commercial formulations of MB intended for aPDT in dentistry, comparing them with analytical-grade MB. The analyzed formulations included various commercial presentations, such as liquid solution, gel, lollipop, and laboratory- prepared aqueous solution. The investigated concentrations ranged from 0.005% (w/v) to 0.01% (w/v), corresponding to 156.3 μM and 312.5 μM, respectively. The results revealed significant spectroscopic variations compared to the analytical-grade MB standard, with a marked trend toward the predominance of the dimeric form in almost all evaluated commercial formulations. This predominance of the dimeric form suggests a favoring of Type I photochemical reactions, which may be particularly relevant for antimicrobial efficacy. The study highlights the importance of optimizing commercial MB formulations to maximize their clinical efficiency in aPDT, especially in scenarios where antibiotic resistance poses significant challenges. Furthermore, the findings contribute to the advancement of identifying more effective formulations, offering a promising alternative for managing dental infections and expanding the therapeutic arsenal available for antimicrobial treatments.Item Efeito antibacteriano do óleo de girassol ozonizado em diferentes concentrações(Universidade Brasil, 2021) Ficher, Ester; Nunez, Silvia CristinaThe world is currently facing a crisis regarding microorganisms and microbial resistance. The evaluation of alternative antimicrobial therapies has been a constant search in recent decades. Ozonized oil can be an alternative within this field. The present study aims to analyze the antimicrobial efficacy of commercially available ozonated sunflower oil in different concentrations. A gram-positive bacteria Staphylococcus aureus and the gram-negative bacteria Escherichia coli were used. The microorganisms were grown in BHI broth (Brain and Heart Infusion) for 24h. Plates containing BHI agar were prepared for the inhibition halo test with a 3 mm diameter central well and contaminated with 50 µL of bacterial suspension. The wells made in the plates were filled with ozonated sunflower oil in concentrations ranging from 80 mmol-Eq / kg to 1290 mmol-Eq /. The plates were taken to the incubator at 37°C for 24h and the inhibition zone was measured with a millimeter probe, two control groups one with non-ozonated sunflower oil and one with 2% chlorhexidine gluconate solution were also evaluated. The results demonstrated that the efficacy for E.coli increases linearly with increasing concentration, however, only the concentrations of 702 mmol-Eq / kg and 1290 mmol-Eq / kg were significantly different (p<0.004). For S.aureus, the results showed significant differences only in the concentration of 1290 mmol-Eq / kg, but with a similar effect between the intermediate and higher concentrations (p<0.0001). The chlorhexidine group demonstrated to have a more effective action for both microorganisms under the conditions of this study (p<0.001). According to the results ozonized sunflower oil has less antimicrobial effect than chlorhexidine, the result is dependent on the concentration and only concentrations above 702 mmol-Eq / kg showed some efficacy.Item Avaliação da razão dímero/monômero nas formulações comerciais de Azul de Metileno empregados na terapia fotodinâmica antimicrobiana.(Universidade Brasil, 2024) Campos, Rosimari Mariano de; Nunes, Silvia CristinaAntimicrobial photodynamic therapy (aPDT) has been extensively studied in dentistry as an effective approach for treating localized infections, including periodontal and endodontic infections. Among the available photosensitizers (PS), methylene blue (MB) stands out as a widely recognized option in scientific literature due to its photodynamic efficiency. This efficiency, however, is directly influenced by the proportion of dimeric and monomeric forms of MB, which are significantly affected by the ionic interactions present in the solution, thereby impacting the PS's performance in photodynamic applications. This study employed spectroscopic methods to evaluate different commercial formulations of MB intended for aPDT in dentistry, comparing them with analytical-grade MB. The analyzed formulations included various commercial presentations, such as liquid solution, gel, lollipop, and laboratory prepared aqueous solution. The investigated concentrations ranged from 0.005% (w/v) to 0.01% (w/v), corresponding to 156.3 µM and 312.5 µM, respectively. The results revealed significant spectroscopic variations compared to the analytical-grade MB standard, with a marked trend toward the predominance of the dimeric form in almost all evaluated commercial formulations. This predominance of the dimeric form suggests a favoring of Type I photochemical reactions, which may be particularly relevant for antimicrobial efficacy. The study highlights the importance of optimizing commercial MB formulations to maximize their clinical efficiency in aPDT, especially in scenarios where antibiotic resistance poses significant challenges. Furthermore, the findings contribute to the advancement of identifying more effective formulations, offering a promising alternative for managing dental infections and expanding the therapeutic arsenal available for antimicrobial treatments.Item Efeito antibacteriano do óleo de girassol ozonizado em diferentes concentrações(Universidade Brasil, 2021) Ficher, Ester; Nuñez, Silvia CristinaThe world is currently facing a crisis regarding microorganisms and microbial resistance. The evaluation of alternative antimicrobial therapies has been a constant search in recent decades. Ozonized oil can be an alternative within this field. The present study aims to analyze the antimicrobial efficacy of commercially available ozonated sunflower oil in different concentrations. A gram-positive bacteria Staphylococcus aureus and the gram-negative bacteria Escherichia coli were used. The microorganisms were grown in BHI broth (Brain and Heart Infusion) for 24h. Plates containing BHI agar were prepared for the inhibition halo test with a 3 mm diameter central well and contaminated with 50 µL of bacterial suspension. The wells made in the plates were filled with ozonated sunflower oil in concentrations ranging from 80 mmol-Eq / kg to 1290 mmol-Eq /. The plates were taken to the incubator at 37°C for 24h and the inhibition zone was measured with a millimeter probe, two control groups one with non-ozonated sunflower oil and one with 2% chlorhexidine gluconate solution were also evaluated. The results demonstrated that the efficacy for E.coli increases linearly with increasing concentration, however, only the concentrations of 702 mmol-Eq / kg and 1290 mmol-Eq / kg were significantly different (p<0.004). For S.aureus, the results showed significant differences only in the concentration of 1290 mmol-Eq / kg, but with a similar effect between the intermediate and higher concentrations (p<0.0001). The chlorhexidine group demonstrated to have a more effective action for both microorganisms under the conditions of this study (p<0.001). According to the results ozonized sunflower oil has less antimicrobial effect than chlorhexidine, the result is dependent on the concentration and only concentrations above 702 mmol-Eq / kg showed some efficacy.