The “Transparent Mice”: Achieving Transient Optical Transparency in Live Animals with Absorbing Molecules

4th September 2025

Timing : 1 pm ET

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For a list of all talks at the NanoBio seminar Series Fall'25, see here


Light plays a central role in science, shaping both how we study living systems and how we perceive the world around us. As we observe in daily life, light has difficulty penetrating living biology tissue, mainly because of scattering and absorption. This limitation hampers the use of light in biological research, often necessitating invasive procedures such as tissue sectioning, insertion of optical fibers or endoscopes, and surgical removal of overlying structures (e.g., craniotomy) to modulate and image biological activity using light microscopy. To address these challenges, we recently developed a new approach to achieve optical transparency in live animals by applying the Kramers-Kronig relations to absorbing dye molecules, treating them as photonic metamaterials within biological tissues. We demonstrated that tissues in living rodents can be rendered optically transparent in a transient, reversible, and repeatable manner through the application of these dye molecules. This method has allowed us to visualize deep-seated structures and functions through optically cleared tissues in live mice, with the potential to enable noninvasive deep-tissue optical imaging and light-based modulation of biological activity.



Snow
Dr. Guosong Hong

Dr. Guosong Hong received his Ph.D. in chemistry from Stanford University in 2014 and then carried out postdoctoral studies at Harvard University. Dr. Hong joined Stanford Materials Science and Engineering and Neurosciences Institute as an assistant professor in September 2018. His research at Stanford focuses on developing and applying novel optical and electronic materials for minimally invasive interfacing with biological systems. He is a recipient of the NIH Pathway to Independence (K99/R00) Award, the MIT Technology Review ‘35 Innovators Under 35’ Award, the Science PINS Prize for Neuromodulation, the NSF CAREER Award, the Walter J. Gores Award for Excellence in Teaching, the Rita Allen Foundation Scholars Award, the Biomedical Engineering Society (BMES) Rising Star Award, the International Conference on Ultrasound Engineering for Biomedical Applications (IC-UEBA) Young Investigator Award, the Camille Dreyfus Teacher-Scholar Award, the Presidential Early Career Award for Scientists and Engineers (PECASE), the Vilcek Prize for Creative Promise in Biomedical Science, and the Materials Research Prize for Young Researchers from ETH Zürich.