A research group led by Prof. Takeshi Imai at Kyushu University has developed a clearing agent, SeeDB-Live, that can render mammalian tissues transparent while preserving normal cellular function. Existing tissue-clearing agents generally have high toxicity and osmolarity, making it difficult to maintain cellular function. In this study, the researchers used albumin to optimize the refractive index of the extracellular medium without increasing osmolarity, thereby enabling noninvasive optical clearing of living tissues, such as brain slices ex vivo and mouse brains in vivo. The study was published in Nature Methods.