title: Recent progress in tissue optical clearing.
abstract: Tissue optical clearing technique provides a prospective solution for the application of advanced optical methods in life sciences. This paper gives a review of recent developments in tissue optical clearing techniques. The physical, molecular and physiological mechanisms of tissue optical clearing are overviewed and discussed. Various methods for enhancing penetration of optical-clearing agents into tissue, such as physical methods, chemical-penetration enhancers and combination of physical and chemical methods are introduced. Combining the tissue optical clearing technique with advanced microscopy image or labeling technique, applications for 3D microstructure of whole tissues such as brain and central nervous system with unprecedented resolution are demonstrated. Moreover, the difference in diffusion and/or clearing ability of selected agents in healthy versus pathological tissues can provide a highly sensitive indicator of the tissue health/pathology condition. Finally, recent advances in optical clearing of soft or hard tissue for in vivo imaging and phototherapy are introduced. [Formula: see text].
authors.affiliation: Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology Wuhan, China ; Key Laboratory of Biomedical Photonics of Ministry of Education, Department of Biomedical Engineering, Huazhong University of Science and Technology Wuhan, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhu
authors.affiliation: Department of Biomedical Engineering, University of Houston, Houston, USA and Department of Physiology and Biophysics, Baylor College of Medicine Houston, USA ; Department of Optics and Biophotonics, Saratov State University Saratov, 410012, Russia.
authors.forename: Kirill V
authors.initials: KV
authors.lastname: Larin
authors.affiliation: Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology Wuhan, China ; Key Laboratory of Biomedical Photonics of Ministry of Education, Department of Biomedical Engineering, Huazhong University of Science and Technology Wuhan, China.
authors.forename: Qingming
authors.initials: Q
authors.lastname: Luo
authors.affiliation: Department of Optics and Biophotonics, Saratov State University Saratov, 410012, Russia ; Laboratory of Laser Diagnostics of Technical and Living Systems, Institute of Precise Mechanics and Control RAS Saratov, 410028, Russia ; Optoelectronics and Measurement Techniques Laboratory, P.O. Box 4500, University of Oulu, FIN-90014 Oulu, Finland.
authors.forename: Valery V
authors.initials: VV
authors.lastname: Tuchin
keywords: OCT; blood-flow imaging; microscopy imaging; molecular diffusion; optical imaging; optical-clearing agents; scattering; tissue