Blue LED system irradiation shows many important properties on skin as: bacterial decontamination, degradation of endogenous skin chromophores and biostimulation. In this clinical study we prove that the blue light improves the skin hydration. In the literature none authors reports this biological property on skin. Then this study aims to discuss the role of blue light in the skin hydration. Twenty patients were selected to this study with age between 25-35 years old and phototype I, II and III. A defined area from forearm was pre determined (A = 4.0 cm2). The study was randomized in two treatment groups using one blue light device (power of 5.3mW and irradiance of 10.8mW/cm2). The first treatment group was irradiated with 3J/cm2 (277seconds) and the second with 6J/cm2 (555 seconds). The skin hydration evaluations were done using a corneometer. The measurements were collected in 7, 14, 21 and 30 days, during the treatment. Statistical test of ANOVA, Tukey and T-Student were applied considering 5% of significance. In conclusion, both doses were able to improve the skin hydration; however, 6J/cm2 has kept this hydration for 30 days.
We used three dimensional cell cultures (3D) based on the magnetic levitation method (MLM) to evaluate cytotoxicity of
photodynamic therapy (PDT). First, we decorated Hep G2 and MDA-MB-321 cells with NanoShuttle by introducing it in
the media and incubated overnight. Next day, we transferred the cells to a 6-well plate and placed a magnetic driver on
the top of the plate to start levitation. We monitored the formation of the 3D cell culture by optical microscopy and after
four days, we added the photosensitizer Photogem (PG) in the culture media in concentrations of 50, 25, 12.5,
6.25μg/ml. We incubated them for 24 hours, after that we washed the cultures with PBS and added fresh media. Samples
were then illuminated for 600s using a 630nm LED-based device, generating light intensities of 30 mW/cm2 in a total light fluence of 18 J/cm2. Following the illumination, we added fresh media, and 30 hours later, the 3D structures were broken using a pipettor and the cells seeded in 96 well plates, 105 cells per well, with a magnetic drive placed on the bottom of the plate to create cell culture dots. After 24 hours, we used a MTT assay to evaluate PDT cytotoxicity. The PDT effect, evaluated by the half maximal effective concentration (EC50), in MDA-MB-231 cells (EC50 =3.14 μg/ml) is more aggressive compared to the effect of PDT in Hep G2 cells (EC50 = 7.48 μg/ml). It suggests that the cell culture structure and its interaction facilitated the PG uptake and consequently elevated the Photodynamic effect for MDA-MB-231.
One of the limitations of topical photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA) is the poor ability to penetrate biological barriers of skin and the recurrence rates in treatments. This study aimed to identify possible signs of increased diffusion of ALA-induced PpIX by fluorescence images and fluorescence spectroscopy. The research was done using in vivo porcine skin model. Before the cream application, microholes was performed with microneedles rollers in only one direction, afterward the ALA cream was applied at a 2.5cm2 area in triplicate and an occlusive dressing was placed. PpIX production was monitored using fluorescence spectroscopy collected at skin surface after 70, 100, 140, and 180 minutes of ALA incubation. About 100 fluorescence spectra of each treatment were collected, distributed by about five points for each site. Wide-field fluorescence imaging was made after 70, 90, and 170 minutes after treatment. The results obtained by imaging analysis indicated increase of the PpIX diffusion in the skin surface using the microneedles rollers (MNs) before ALA application. Circular regions of red fluorescence around the microholes were observed. In addition, the fluorescence spectra showed a greater intensity (2 times as many) in groups microneedles rollers associated. In conclusion, our data shown greater homogeneity and PpIX production in the groups pre-treated with microneedles indicating that the technique can be used to greater uniformity of PpIX production throughout the area to be treated reducing the chances of recurrent tumor as well as has potential for decreasing the time of therapy. (FUNDING SUPPORT:CAPES, CNPq and FAPESP)
The skin aging process is mainly accelerated by external agents such as sunlight, air humidity and
surfactants action. Changes in protein structures and hydration during the aging process are
responsible for skin morphological variations. In this work the human skin was investigated by in vivo
Raman spectroscopy before and after the topical applications of a cosmetic on 17 healthy volunteers
(age 60 to 75). In vivo Raman spectra of the skin were obtained with a Spectrometer SpectraPro- 2500i
(Pi-Acton), CCD detector and a 785 nm laser excitation source, collected at the beginning of experiment
without cream (T0), after 30 (T30) and 60 (T60) days using the product. The primary changes occurred
in the following spectral regions: 935 cm-1 (νCC), 1060 cm-1 (lipids), 1174 to 1201 cm-1 (tryptofan,
phenylalanine and tyrosine), 1302 cm-1 (phospholipids), 1520 to 1580 cm-1 (C=C) and 1650 cm-1 (amide
I). These findings indicate that skin positive effects were enhanced by a continuous cream application.
Photodynamic therapy (PDT) is a technique for inducing tissue damage with light irradiation of a drug selectively retained in malignant tissue in presence of oxygen. The same mechanisms responsible for PDT efficacy can destroy the sensitizer, a process called photobleaching. In this work, the photobleaching of Photogem (a hematoporphyrin derivative used in Brazil made in Russia) was induced to study phototoxicity of the photoproducts upon a tumor (HEp-2) and non-tumor (VERO) cell line. Photogem was previously irradiated at 514nm and 630 nm (50mW/cm2) for 120 min. The sensitizer photobleaching was monitored by fluorescence and absorption properties changes and photoproducts formation evidenced by the appearance of a new absorption band around 640nm. Irradiated and non-irradiated Photogem were incubated for 18h with the cells. After drug removal, cells were irradiated with LED at 630 nm with intensities of 13, 20 and 25mW/cm2 for different times. Then, the cells were incubated for 48 hours to determine the cells viability by the MTT method. The cells in the dark were used as control. The IC50 decreases as light intensity increases, being more pronounced for tumor cells. Previously irradiated Photogem needs one-hour irradiation for both cell lines to have the same IC50 value of non-irradiated Photogem, which are irradiated for 14 min in tumor cells and 25 min in non-tumor cells. The results suggest that the photoproducts of Photogem are less cytotoxic either in the dark or in the light, decreasing with increase of intensity. These results underline the importance of dosimetry in PDT.
Porphyrins can be degraded by light. Photogem is a photosensitizer used in PDT in Brazil. Photogem irradiation at 514 and 630 nm change its fluorescence and absorption due to photodegradation and photoproducts formation (new absorption band in 640 nm). Irradiated Photogem was incubated with tumor or non-tumor cells. The low toxicity suggests that the photoproducts of Photogem are less cytotoxic than the original formulation.
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