The Optical Clearing Method: A New Tool for Clinical Practice and Biomedical Engineering

This book describes the Optical Immersion Clearing method and its application to acquire information with importance for clinical practice and various fields of biomedical engineering. The method has proved to be a reliable means of increasing tissue transparency, allowing the investigator or surgeon to reach deeper tissue layers for improved imaging and laser surgery. This result is obtained by partial replacement of tissue water with an active optical clearing agent (OCA) that has a higher refractive index and is a better match for the refractive index of other tissue components. Natural tissue scattering is thereby reduced. An exponential increase in research using this method has occurred in recent years, and new applications have emerged, both in clinical practice and in some areas of biomedical engineering. Recent research has revealed that treating ex vivo tissues with solutions containing active OCAs in different concentrations produces experimental data to characterize drug delivery or to discriminate between normal and pathological tissues. The obtained drug diffusion properties are of interest for the pharmaceutical and organ preservation industry. Similar data can be estimated with particular interest for food preservation. The free water content evaluation is also of great interest since it facilitates the characterization of tissues to discriminate pathologies. An interesting new application that is presented in the book regards the creation of two optical windows in the ultraviolet spectral range through the application of the immersion method. These induced transparency windows open the possibility to diagnose and treat pathologies with ultraviolet light. This book presents photographs from the tissues we have studied and figures that represent the experimental setups used. Graphs and tables are also included to show the numerical results obtained in the sequential calculations performed.

Luís Oliveira graduated in Physics in 2000 from Porto University – School of Sciences. Later, in 2010 and 2014, he received the M.S. and PhD degrees from the same University – School of Engineering. Since 2001 he has been a researcher in the field of optics, later specializing in the field of biophotonics. He is a Professor (Adjunct) at the Physics Department of the Polytechnic Institute of Porto – School of Engineering since 2008. He is also a senior researcher in biophotonics at the Center of Innovation in Engineering and Industrial Technology, a research center that is part of the Polytechnic of Porto. In recent years, Prof. Oliveira has reviewed and authored several papers in the fields of tissue optics and tissue optical clearing. He has one patent pending regarding the discovery of two tissue windows in the ultraviolet. His main research interests include tissue optics, tissue optical clearing and related clinical applications to diagnose and treat pathologies. 

Valery V. Tuchin is a professor and chair of Optics and Biophotonics at Saratov State University (National Research University of Russia) and several other universities and academic Institutes in Russia and abroad. His research interests include tissue optics, laser medicine, tissue optical clearing, and nanobiophotonics. He is a fellow of SPIE and OSA, he was awarded the Honored Science Worker of Russia, Honored Professor of Saratov State University, SPIE Educator Award, FiDiPro (Finland), Chime Bell Prize of Hubei Province (China), Joseph W. Goodman Book Writing Award (OSA/SPIE), and OSA Michael S. Feld Biophotonics Award for pioneering research in biophotonics. He has published more than 700 papers (Web of Science), 27 monographs and text-books, and 58 book chapters. Dr. Tuchin is also a holder of more than 50 patents. His works were cited 24,636 times to August, 2019 (Google Scholar).