RESUMO
Nanohybrids of enriched (6,5) single-walled semiconducting carbon nanotubes (E-SWCNTs) and porphyrin can be used synergistically as photodynamic therapy (PDT) agents. The efficiency of different porphyrins within the nanohybrids was investigated and compared with results obtained from porphyrins in previous studies. Reactive oxygen species singlet oxygen (1)O2 and for the first time hydroxyl radical ËOH generation by the nanohybrids under illumination were detected by electron paramagnetic resonance using spin trapping molecules TEMP and PBN. Based on the analysis, we improve the modelling of charge transport within the nanohybrids, which is also detected by Raman scattering. It is shown that the 5,10,15,20-tetrakis(4-trimethylammoniumphenyl)porphyrin [H2TTMAPP(OTs)4] and E-SWCNT form very efficient nanohybrids for PDT applications in the visible spectral range.
RESUMO
Environmental contamination by pharmaceuticals from industrial waste and anthropogenic activities poses adverse health effects on non-target organisms. We evaluated the neurobehavioral and biochemical responses accompanying exposure to ecological relevant concentrations of atenolol (0, 0.1, 1.0, and 10 µg/L) for seven uninterrupted days in adult zebrafish (Danio rerio). Atenolol-exposed fish exhibited anxiety-like behavior, characterized by significant bottom-dwelling with marked reduction in vertical exploration. Atenolol-exposed fish exhibited marked increase in the duration and frequency of aggressive events without altering their preference for conspecifics. Biochemical data using brain samples indicated that atenolol disrupted antioxidant enzyme activities and induced oxidative stress. Exposure to atenolol markedly decreased ATP and AMP hydrolysis without affecting ADP hydrolysis and acetylcholinesterase (AChE) activity. Atenolol significantly upregulated tryptophan hydroxylase 1 (tph1) mRNA expression but downregulated brain-derived neurotrophic factor (bdnf) mRNA. Collectively, waterborne atenolol elicits aggressive and anxiety-like responses in adult zebrafish, accompanied by oxidative stress, reduced nucleotide hydrolysis, altered tph1 and bdnf mRNA expression, which may impact the survival and health of fish in aquatic environment.
Assuntos
Atenolol , Comportamento Animal , Estresse Oxidativo , Poluentes Químicos da Água , Peixe-Zebra , Animais , Atenolol/farmacologia , Poluentes Químicos da Água/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Triptofano Hidroxilase/metabolismo , Triptofano Hidroxilase/genética , Fator Neurotrófico Derivado do Encéfalo/metabolismoRESUMO
Gold nanostructures of two different shapes (spheres and rods) were synthesized to form a colloidal hybrid system with 5,10,15,20-tetrakis(N-methylpyridinium-4-yl)porphyrin tosylate salt (H2TM4PyP(OTs)4) (POR) for applications in photodynamic therapy (PDT) using light in the visible spectral range. Electron paramagnetic resonance (EPR) experiments in combination with spin trapping were used for the detection of reactive oxygen species (ROS) and evaluation of the efficiency of these novel hybrid systems as photosensitizers. It is shown that the hybrid system consisting of gold nanorods (AuNR) and porphyrin (POR) is by far more efficient than its isolated components. This enhanced efficiency is explained by a synergetic effect between the AuNR and the porphyrin, wherein a rapid energy transfer from the former to the latter produces a large amount of singlet oxygen followed by its conversion into hydroxyl radicals. The mechanism was investigated using different spin traps and different ROS inhibitors. On the other hand, spherical gold nanoparticles (AuNP) do not show this synergetic effect. The synergetic effect for gold nanorods/POR hybrid is attributed to a larger field enhancement close to the gold nanorod surface in addition to the electrostatic attraction between the components of the hybrid system.