Synergistic effect of carboxypterin and methylene blue applied to antimicrobial photodynamic therapy against mature biofilm of Klebsiella pneumoniae.

The control of multidrug-resistant (MDR) bacteria is a growing public health problem, and new strategies are urgently needed for the control of the infections caused by these microorganisms. Notoriously, some MDR microorganisms generate complex structures or biofilms, which adhere to surfaces and confer extraordinary resistance properties that are fundamental challenges to control infections. One of the promising strategies for the control of MDR bacteria is antimicrobial photodynamic therapy (aPDT), which takes advantage of suitable photosensitizers (PS), oxygen and radiation to eradicate microorganisms by the generation of highly reactive species, including reactive oxygen species (ROS) that cause cytotoxic damage and cell death. Habitual aPDT treatments use only methylene blue (MB), but MDR microorganism eradication is not completely achieved. The key result of this study revealed that a combination of two known PSs, 6-carboxypterin (Cap, 100 µM) and MB (2.5-10 µM) exposed to ultraviolet and visible radiation, presents a synergistic effect on the eradication of a MDR Klebsiella pneumoniae strain. Similar effect was observed when the treatment was performed either with planktonic or biofilm growing cells. Moreover, it was found that after treatment the killing action continues in the absence of irradiation leading to the eradication of the microorganisms growing in biofilm. Therefore, the combined aPDT represents a promising strategy for the management of clinical contact surfaces, disinfection of surgical instruments, biofouling and even antimicrobial wastewater treatment.

Comparative study of transdermal drug delivery systems of resveratrol: High efficiency of deformable liposomes.

Trans-resveratrol (3, 5, 4' trihydroxystilbene, RSV) is a natural compound that shows antioxidant, cardioprotective, anti-inflammatory and anticancer properties. The transdermal, painless application of RSV is an attractive option to other administration routes owing to its several advantages like avoiding gastrointestinal problems and first pass metabolism. However, its therapeutic potential is limited by its low solubility and low stability in water and the reduced permeability of stratum corneum. To overcome these inconveniences the encapsulation of this compound in a drug delivery system is proposed here. In order to find the best carrier for transdermal application of RSV various liposomal nanoparticulate carriers like conventional liposomes (L-RSV), deformable liposomes (LD-RSV), ultradeformable liposomes (LUD-RSV) and ethosomes (Etho-RSV) were assayed. Transmission electron microscopic (TEM) and dynamic light scattering (DLS) studies were performed to analyze the surface morphology of these carriers. Structural characterization for these formulations was performed by confocal Raman spectroscopy. The spectroscopic results were analysed in conjunction with calorimetric data to identify the conformational changes and stability of formulations in the different nanoparticles induced by the presence of RSV. Comparison of the results obtained with the different carrier systems (L-RSV, LD-RSV, LUD-RSV and Etho-RSV) revealed that the best RSV carrier was LD-RSV. The increase in the fluidity of the bilayers in the region of the hydrophobic chains of the phospholipid by ethanol probably facilitates the accommodation of the RSV in the bilayer and contributes to the improved encapsulation of RSV without affecting the mobility of this carrier.

Resveratrol enhancement staphylococcus aureus survival under levofloxacin and photodynamic treatments.

Reactive oxygen species (ROS) are an efficient tool to eradicate micro-organisms owing to the capacity of these species to damage almost all types of biomolecules and to kill cells. The increase in mechanisms of antimicrobial resistance has led to the exploration of new strategies to eliminate micro-organisms that involve the production of ROS such as superoxide anion (O2•-) and hydrogen peroxide (H2O2). ROS are produced during several antimicrobial treatments, including antibiotic and photodynamic therapies. Among the natural antioxidants, resveratrol (RSV) is efficient at preventing damage from ROS, and every day more people incorporate it as a dietary or cosmetic supplement. However, the consequences of the administration of RSV during antimicrobial treatment are unknown. To investigate possible antagonistic or synergistic effects of RSV during antibiotic therapy (levofloxacin) or photodynamic therapy (visible radiation and methylene blue), killing of planktonic Staphylococcus aureus bacteria was evaluated in the presence of RSV. The results showed that the antimicrobial capacity of these therapies is significantly diminished when levofloxacin or methylene blue are co-administered with RSV, indicating that consumption of RSV during antimicrobial treatment must be, at least, cautioned. Moreover, considering the ROS antimicrobial activity of antibacterial agents, the topical addition of RSV may also affect the control of pathogens of the human body. The results presented in this article highlight the importance of the evaluation of possible antagonistic effects when an antimicrobial agent with ROS-mediated action is co-administrated with RSV.

Influence of mycosporine-like amino acids and gadusol on the rheology and Raman spectroscopy of polymer gels.

BACKGROUND: The amphiphilic nature of polymers allows them to be widely incorporated as carriers in different pharmaceutical applications since they are able to work as vehicles for hydro- or lipo-soluble actives. OBJECTIVE: The aim of this study was to determine the rheological behavior and vibrational spectral variations of two hydrophilic gels prepared with Poloxamer 407 (PO) or Pluronic F-127 (PL) with the addition of the actives mycosporine-like amino acids and gadusol. METHODS: The structures of these polymers in two different concentrations (20% w/w and 27% w/w) were characterized by rheological studies and Raman spectroscopy. RESULTS: Gels prepared with higher polymer concentration showed larger G' (storage modulus) values. The C-C stretch and the CH2 rocking predominated in the gels containing PL (20% w/w) and this correlated with a less viscous behavior. The mixture of the actives induced higher contributions of Raman peaks related to trans conformation of the C-C bonds located in hydrophilic polymer blocks, whereas the same peaks decreased in the sample containing only gadusol. CONCLUSIONS: Larger tensile strength and elastic component were observed upon increasing polymer concentration, thus evidencing polymer-polymer and/or polymer-polymer-actives interactions. The presence of the actives affected the mechanical properties of the polymer gels. Gadusol particularly seems to alter the conformation of the polymer chains by favoring gauche orientations, in parallel with rising viscoelastic parameters. More stretched arrangements of the polymer are probably induced in the presence of larger concentration of actives, due to specific interactions with their hydrophilic groups.

Confocal Raman spectroscopy: determination of natural moisturizing factor profile related to skin hydration

INTRODUCTION: Skin health and skin care to reduce the effects of aging are the main interests of many researchers. The skin is very important because it protects the body from various effects of the external environment, and studies of the largest organ of the human body have been conducted since antiquity. In skin, aging effects are severe enough to promote changes in cell structure and biochemical composition. In this study, we quantitatively analyzed the water content and natural moisturizing factor of human facial skin in vivo and in real time by confocal Raman spectroscopy. This non-invasive technique is capable of providing detailed information on the biochemical composition at different depth profiles in the skin. METHODS: We studied 10 volunteers, phototype II (40 and 50 years old), using a confocal Raman system to examine the skin surface down to 25 µm. Raman spectra were obtained before product use (T0), and after 30 days of continuous use of cosmetics (T30). RESULTS: The results show a significant increase of 6.4% in water content in the surface layer of the facial skin after the cosmetic use. The amounts of natural moisturizing factor (NMF) compounds were also increased. Urocanic acid underwent a greater change in relation to carboxylic acid pyrrolidone, with a 38.5% increase in the stratum corneum. CONCLUSION: Confocal Raman spectroscopy identified changes in the biochemical composition of the superficial layers of the epidermis, which suggests the anti-aging efficacy of the formulation.

Análise da composição bioquímica da pele por espectroscopia Raman / Skin biochemical composition analysis by Raman spectroscopy

O envelhecimento cutâneo caracteriza-se por alterações celulares e moleculares. Neste contexto, a espectroscopia Raman Confocal foi utilizada para medir estas alterações bioquímicas em função da profundidade da pele in vivo. Neste estudo houve a tentativa de correlacionar os modos vibracionais dos aminoácidos puros com os espectros da pele de voluntárias de diferentes faixas etárias. Foram coletados espectros in vivo de 32 voluntárias, sendo 11 para o Grupo A (20-23 anos), 11 para o Grupo B (39-42 anos) e 10 para o Grupo C (59-62 anos). Para cada grupo, os espectros Raman foram medidos na superfície (0 µm), 30 ± 3 µm e 60 ± 3 µm. Os resultados das comparações intergrupos mostraram que o grupo de maior idade teve prevalência da banda da tirosina, mas também apresentou um decréscimo da banda do ácido pirrolidônico, centrada em 875 cm-1. A banda da amida I, centrada em 1637 cm-1, atribuída à presença de colágeno, como também outras proteínas e lipídeos, apresentou uma menor intensidade no Grupo C, o que pode ser justificado pelo decréscimo na concentração de colágeno em função da idade.

Skin aging is characterized by cellular and molecular alterations. In this context, Confocal Raman spectroscopy was used in vivo to measure these biochemical changes as function of the skin depth. In this study we have tried to correlate spectra from pure amino acids to in vivo spectra from volunteers with different ages. This study was performed on 32 volunteers: 11 from Group A (20-23 years), 11 from Group B (39-42 years) and 10 from Group C (59-62 years). For each group, the Raman spectra were measured on the surface (0 µm), 30 ± 3 µm and 60 ± 3 µm below the surface. The results from intergroup comparisons showed that the oldest group had a prevalence of the tyrosine band, but it also presented a decrease in the band centered at 875 cm-1 of pyrrolidone acid. The amide I band centered at 1637 cm-1 that is attributed to collagen, as well as other proteins and lipid, showed a smaller amount of these biomolecules for Group C, which can be explained by the decrease in collagen concentration as a function of age.

Influence of creatine supplementation on bone quality in the ovariectomized rat model: an FT-Raman spectroscopy study.

The influence of creatine (Cr) supplementation on cortical and trabecular bone from ovariectomized rats was studied using FT-Raman spectroscopy. The intensity of organic-phase Raman bands was compared to mineral phase ones. Twenty-one female Wistar rats aged 3 months were divided into three groups (n = 7 per group): ovariectomized (OVX), ovariectomized treated with creatine (CRE) and sham-operated (SHAM) groups. Creatine supplementation (300 mg kg(-1) day(-1)) was provided for 8 weeks, starting 12 weeks after ovariectomy. FT-Raman spectroscopy was performed on the right medial femoral mid-shaft (cortical bone) and third lumbar vertebral body (trabecular bone). The integrated intensities of mineral phase (phosphate and carbonate bands at 959 and 1,071 cm(-1), respectively) and organic phase (amide I band at 1,665 cm(-1)) Raman bands were analyzed. The mineral-to-matrix (phosphate/amide I), carbonate-to-phosphate, and carbonate-to-amide I ratios were analyzed to assess bone quality. The phosphate content on trabecular bone was higher in the CRE group than the OVX group (p < 0.05). No significant changes in mineral or organic phases on cortical bone were observed. A radiographic assessment of bone density was encouraging as the same findings were showed by Raman intensity of phosphate from cortical (r(2) = 0.8037) and trabecular bones (r(2) = 0.915). Severe ovariectomy-induced bone loss was confirmed by FT-Raman spectroscopy. The results suggest that the chemical composition of trabecular bone tissue may be positively influenced by Cr supplementation after ovariectomy.