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1.
Int J Mol Sci ; 24(21)2023 Nov 04.
Artículo en Inglés | MEDLINE | ID: mdl-37958951

RESUMEN

Bacterial resistance to antibiotics is a critical global health issue and the development of alternatives to conventional antibiotics is of the upmost relevance. Antimicrobial photodynamic therapy (aPDT) is considered a promising and innovative approach for the photoinactivation of microorganisms, particularly in cases where traditional antibiotics may be less effective due to resistance or other limitations. In this study, two ß-modified monocharged porphyrin-imidazolium derivatives were efficiently incorporated into polyvinylpyrrolidone (PVP) formulations and supported into graphitic carbon nitride materials. Both porphyrin-imidazolium derivatives displayed remarkable photostability and the ability to generate cytotoxic singlet oxygen. These properties, which have an important impact on achieving an efficient photodynamic effect, were not compromised after incorporation/immobilization. The prepared PVP-porphyrin formulations and the graphitic carbon nitride-based materials displayed excellent performance as photosensitizers to photoinactivate methicillin-resistant Staphylococcus aureus (MRSA) (99.9999% of bacteria) throughout the antimicrobial photodynamic therapy. In each matrix, the most rapid action against S. aureus was observed when using PS 2. The PVP-2 formulation needed 10 min of exposure to white light at 5.0 µm, while the graphitic carbon nitride hybrid GCNM-2 required 20 min at 25.0 µm to achieve a similar level of response. These findings suggest the potential of graphitic carbon nitride-porphyrinic hybrids to be used in the environmental or clinical fields, avoiding the use of organic solvents, and might allow for their recovery after treatment, improving their applicability for bacteria photoinactivation.


Asunto(s)
Antiinfecciosos , Staphylococcus aureus Resistente a Meticilina , Fotoquimioterapia , Porfirinas , Staphylococcus aureus , Porfirinas/farmacología , Fármacos Fotosensibilizantes/farmacología , Antibacterianos/farmacología , Povidona/farmacología
2.
Photochem Photobiol ; 89(3): 560-70, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23360126

RESUMEN

The photochemical degradation of 2-(1-naphthyl) acetamide (NAD) in aqueous solution using simulated sunlight excitation as well as UV light within the 254-300 nm range was investigated to obtain an insight into the transformation mechanism that could occur under environmental conditions. Several photoproducts were identified using HPLC/MS/MS techniques. The degradation quantum yield was found to be independent of the excitation wavelength, but showed a dependence of oxygen concentration. This increased by a factor of approximately 3 from aerated to oxygen-free solutions. There is a clear involvement of both triplet and singlet excited states in NAD photoreactivity. The participation of singlet oxygen as a significant route in NAD degradation was ruled out by comparison with the behavior using Rose Bengal as a photosensitizer. A mechanistic pathway implying hydroxylation process through NAD radical cation species as well as an oxidation reaction by molecular oxygen is proposed. The photochemical behavior of NAD appears to mainly involve the aromatic moieties without any participation of the amide side chain. Toxicity tests clearly show that the generated primary photoproducts are responsible for a significant increase in the toxicity. However, upon prolonged irradiation this toxicity tends to decrease.


Asunto(s)
Ácidos Naftalenoacéticos/química , Oxígeno/química , Reguladores del Crecimiento de las Plantas/química , Oxígeno Singlete/química , Contaminantes Químicos del Agua/química , Aliivibrio fischeri/efectos de los fármacos , Aliivibrio fischeri/crecimiento & desarrollo , Cromatografía Líquida de Alta Presión , Cinética , Viabilidad Microbiana/efectos de los fármacos , Ácidos Naftalenoacéticos/toxicidad , Oxidación-Reducción , Fotólisis , Fármacos Fotosensibilizantes/química , Reguladores del Crecimiento de las Plantas/toxicidad , Rosa Bengala/química , Espectrometría de Masas en Tándem , Termodinámica , Rayos Ultravioleta , Contaminantes Químicos del Agua/toxicidad
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