Impact of e-cigarette liquid on porcine lung tissue - ex vivo confocal Raman micro-spectroscopy study.

Ex vivo porcine lung immersed in e-liquid was investigated in-depth using confocal Raman micro-spectroscopy to assess the e-liquid influence on the lung. It was found that lung-related Raman band intensities at 1002, 1548, 1618 and 1655 cm -1 increased after first and second treatments except the surface, which was attributed to the well-known optical clearing effect due to alveoli filling with e-liquid resulting in light scattering reduction. The autofluorescence enhancement was explained by oxidative stress induced in lung during exposure to e-liquid. Moreover, e-liquid induced collagen dehydration was revealed by the I 937 /I 926 Raman band intensity ratio change. The effect was enhanced after the second treatment of the same lung tissue that indicates the possibility of multi-step OC treatment. We hypothesize that the nicotine-flavour free e-liquids containing glycerol and propylene glycol could potentially be used in clinical protocols as optical clearing agent for enhanced in-depth Raman-guided bronchoscopy. This article is protected by copyright. All rights reserved.