E-cigarette smoking vape impact on optical properties of porcine gingival mucosa measured ex vivo in the range from 200 to 800 nm
Optical properties of the porcine gingival mucosa under the influence of smoking vapes (mixtures of propylene glycol, glycerol, and water) using diffuse transmission and reflection spectroscopies were studied in a wide spectral range from UV to NIR. The principle of diffuse spectroscopy is based on the ability of tissue biological molecular chromophores (hemoglobin, oxyhemoglobin, collagen, DNA, etc.) to absorb diffusely scattered light of a certain wavelength. Scattering is a key feature in light transport and attenuation in tissues, especially in UV. Thus immersion optical clearing provided my tissue impregnation with smoking liquids may have a great impact on tissue optical properties. In this study, for the porcine gingival mucosa the specific features of tissue optics with formation of three dynamic optical windows in the UV were revealed. By combining the immersion technique with UV-spectroscopy, it was possible to verify and study the major optical clearing mechanisms - tissue dehydration and refractive index matching, and to discover that the optical clearing efficiency is much higher in the deep-UV than in the visible-NIR range. These results proof that the refractive index mismatch in tissues is strong in the UV wavelength range, which causes a strong light scattering. Suppression of light scattering of the oral mucosa at application of smoking liquid can be included in clinical protocols for personalized treatment of dental diseases using phototherapy, physiotherapy, photodynamic therapy, laser treatment and optical diagnostics. Fortunately, e-cigarette smoking vapes are certified by medical agencies around the world for human use.
Alexey A. Selifonov
Children's Infectious Disease Clinical Hospital No. 5 "Children's Polyclinic No. 3", Saratov 410031, Russia
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