title: A comparative study of ex vivo skin optical clearing using two-photon microscopy.
abstract: Multiphoton tomography (MPT) is a prospective tool for imaging the skin structure. Aiming to increase the probing depth, a comparative ex vivo study of optical clearing of porcine ear skin was performed by using two optical clearing agents (OCAs), i.e., glycerol and iohexol (OmnipaqueTM) at different concentrations, which exhibit different osmotic properties. The results show that a topical application of glycerol or OmnipaqueTMsolutions onto the skin for 60 min significantly improved the depth and contrast of the MPT signals. By utilizing 40%, 60% and 100% glycerol, and 60% and 100% OmnipaqueTMit was demonstrated that both agents improve autofluorescence and SHG (second harmonic generation) signals from the skin. At the applied concentrations and agent time exposure, glycerol is more effective than OmnipaqueTM. However, tissue shrinkage and cell morphology changes were found for highly concentrated glycerol solutions. OmnipaqueTM, on the contrary, increases the safety and has no or minimal tissue shrinkage during the optical clearing process. Moreover OmnipaqueTMallows for robust multimodal optical/X-ray imaging with automatically matched optically cleared and X-ray contrasted tissue volumes. These findings make OmnipaqueTMmore prospective than glycerol for some particular application.
authors.affiliation: Research-Education Institute of Optics and Biophotonics, Saratov National Research State University, Astrakhanskaya 83, 410012, Saratov, Russian Federation.
authors.forename: Anton
authors.initials: A
authors.lastname: Sdobnov
authors.affiliation: Center of Experimental and Applied Cutaneous Physiology, Department of Dermatology, Venerology and Allergology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
authors.forename: Maxim E
authors.initials: ME
authors.lastname: Darvin
authors.affiliation: Center of Experimental and Applied Cutaneous Physiology, Department of Dermatology, Venerology and Allergology, Charité - Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
authors.forename: Juergen
authors.initials: J
authors.lastname: Lademann
authors.affiliation: Research-Education Institute of Optics and Biophotonics, Saratov National Research State University, Astrakhanskaya 83, 410012, Saratov, Russian Federation.|Laboratory of Laser Diagnostics of Technical and Living Systems, Institute of Precision Mechanics and Control RAS, Rabochaya 24, 410028, Saratov, Russian Federation.|Interdisciplinary Laboratory of Biophotonics, National Research Tomsk State University, Lenin's av. 36, 634050, Tomsk, Russian Federation.
authors.forename: Valery
authors.initials: V
authors.lastname: Tuchin
mesh_terms: D000818:Animals; D005990:Glycerol / Q000737:chemistry; D007472:Iohexol / Q000737:chemistry; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D061848:Optical Imaging / Q000379:methods*; D017785:Photons; D011446:Prospective Studies; D012867:Skin / Q000000981:diagnostic imaging*; D013552:Swine
chemical_list: D007472:Iohexol; D005990:Glycerol
keywords: OmnipaqueTM; glycerol; multiphoton tomography; optical clearing; porcine skin