KCS

In the past, animal testing has been performed on living animals for purpose of assessing the possible negative effectiveness on human. However, it has been issued that problem of ethics like animal abuse and question on the necessity of animal testing when symptom only appears on human. Rather than animal testing, biomedical analysis utilizing an organoid has become an attention-drawing alternative. An organoid is cultivated from human stem cell and has similar cell composition with real organs. Therefore, toxicity test and drug reactions using organoid would be more effective than using other animals. Simultaneously, an analytical tool able to non-destructively analyze a live organoid becomes critically demanding since the destruction of organoid for analysis is not practically allowed for continuation of related toxicological and biomedical research. To meet the demand, Raman spectroscopy based on a wide area illumination (WAI) scheme providing a laser illumination diameter of 1 mm was explored. For the study, normal liver organoids (control group) were cultivated and other organoids were also prepared as non-alcoholic fatty liver (NASH) using culture medium with high fatty acid concentration. Simultaneously, to increase Raman signal of small-size organoids, a cone-shape metal-reflective cavity was prepared and the organoids with culture medium was transferred into the cavity. Then, the WAI scheme covering the whole organoids in the cavity was used to acquire corresponding Raman spectra. Raman spectral features of the control and NASH organoids were compared with each other and their differences were discussed.