The use of diffuse reflection spectroscopy made it possible to determine the optical properties of the mucous membrane of the oral cavity of a pig. The binary diffusion coefficient of iodine in Lugol's composition (aqueous solution of iodine (0.01 w/w), potassium iodide (0.02 w/w) and glycerol (0.94 w/w)) was determined for the first time ex vivo in the lining of the alveolar gingiva pigs: (8.86±0.75)·10–7 cm2/s. For the first time, the binary diffusion coefficient of glycerol was determined in the composition of Lugol (an aqueous solution of iodine (0.01 w/w), potassium iodide (0.02 w/w), and glycerol (0.94 w/w)) ex vivo in the lining of the alveolar gingiva pigs: (6.44±0.62)·10-7 cm2/s. It was revealed that after complete staining of the gingiva with a dye, radiation does not pass into the biological tissue from 200-600 nm, which includes the areas of iodine absorption peaks, and starting from 650-800 nm, the effect of optical clearing is observed with an efficiency of up to 120%.
The work is devoted to determining the diffusion coefficient of methylene blue in human gum tissue in vitro using spectroscopic methods. The calculations are based on the application of the free diffusion model, the second Fick law, and the modified Bouguer – Lambert – Beer law. For the first time, the diffusion coefficient of methylene blue into the tissue of the human gingival mucosa in vitro was determined, which, by averaging 10 samples is (1.26±0.34)·10–7 cm2/s. It was revealed that after the gum is completely stained with dye, the light does not pass into the biological tissue from 200-699 nm, which includes the areas of dye absorption peaks necessary for photoactivation of the dye during photodynamic therapy. The results obtained are important for the personified choice of this method in vivo in the treatment of superficial pathological localizations.
The work is devoted to the determination of the antibacterial activity of methylene blue under the action of ultraviolet radiation, laser radiation (660 nm), as well as their combined effect on standard strains of the bacteria Candida albicans, Staphylococcus aureus FDA 209P and Lactobacillus in vitro. When exposed to all the tested strains, a tendency was revealed with the most pronounced inhibitory effect with the combined action of laser and ultraviolet radiation together with the MB solution. Clinical studies of the in vivo use of methylene blue with the combined effect of ultraviolet and laser radiation (660 nm) in the treatment of chronic recurrent aphthous stomatitis in humans have also been conducted.
The work is devoted to the determination of the diffusion coefficients of methylene blue (MB) in pure aqueous and 40%-glucose-aqueous solutions in human tooth dentinal sections in vitro using diffuse reflectance optical spectroscopy and the free diffusion model. The determination of the diffusion coefficient of MB in a biological tissue was based on the measurement of the temporal kinetics of changes in the diffuse reflectance spectrum. Obviously, the diffusion rate along the dentinal tubules should be the greatest, close to that in water, taking into account some reduction in speed due to interaction with the walls, since they are filled up with a liquid with a high water content. In addition, the density of the dentinal tubules is large enough, so we can expect that their contribution to the total diffusion will be significant. It was determined that the diffusion coefficientfor 0.001% MB in an aqueous solution is (6.74±1.32)·10−6 cm2 and in 40%-glucose solution is (3.89±0.85)·10−6 cm2/s.
Study of the penetration depth of synthesized copper nanoparticles into cut samples of human dentin was conducted. The scanning electron microscopy was used to determine the elemental composition of fresh transverse cleavage of the dentin cut for determination of the copper nanoparticles penetration with an effective antiseptic effect. The morphology of the cut surface of the dentin of a human tooth was studied and the lower limit of the diffusion boundary was determined. It was found that copper nanoparticles penetrate into the dentin cut to a depth of ~ 1.8 μm with the diffusion coefficient of 1.8×10–11 cm2/s. Despite the rather small size of the synthesized copper nanoparticles (20-80 nm), a rather small penetration depth can be explained by the high aggregation ability of copper nanoparticles, as well as the ability of a micellar solution of sodium dodecyl sulfate, in which nanoparticles were stabilized, to form conglomerates in micelles of much larger sizes.
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