Background: Advancements in genome editing technology and the globalization of life science research have highlighted the need for refined techniques in individualizing fertilized mouse eggs. Traditional embryo transfer surgery, which demands precise and objective success assessment, presents challenges for technical mastery and animal welfare. To address these issues, we developed a novel culture medium incorporating a dye library that enhances the visibility of ultrafine capillaries. Results: We screened 32 compounds based on their color properties and excluded those with clear cytotoxicity through colony formation inhibition tests. Five compounds demonstrated developmental outcomes comparable to those of the control group during embryo culture. Gene expression analysis revealed high correlation with control embryos, indicating no adverse developmental impact. No maternal toxicity was observed during and after embryo transfer using the dyed medium, which also produced normal offspring. A randomized survey confirmed improved visibility compared to conventional methods. Conclusion This study successfully identified nontoxic dyes that enhance the visibility of embryo transfer culture media, potentially improving precision and animal welfare in embryological research. Based on our findings, adding Brilliant Blue FCF or Fast Green FCF to the medium is recommended.

Every local government in Japan is seeking to have an integrated health, medical and welfare system to take care of an increasing number of the elderly.
An attempt to develop such a model system called ‘Fukushi no Mori’ was begun in 1987 in Koga City, Ibaraki Prefecture. It was not until 1993 that the land for the project was acquired and the final plans for the arrangement of facilities were drawn up. In March 1994 construction got under way.
This paper discusses the strategies for developing an integrated health, medical and welfare system in this city. The results of a number of detailed research studies undertaken by the authors are also described and discussed.

Every local government in Japan is seeking to have an integrated health, medical and welfare system to take care of an increasing number of the elderly.
An attempt to develop such a model system called ‘Fukushi no Mori’ was begun in 1987 in Koga City, Ibaraki Prefecture. It was not until 1993 that the land for the project was acquired and the final plans for the arrangement of facilities were drawn up. In March 1994 construction got under way.
This paper discusses the strategies for developing an integrated health, medical and welfare system in this city. The results of a number of detailed research studies undertaken by the authors are also described and discussed.

Every local government in Japan is seeking to have an integrated health, medical and welfare system to take care of an increasing number of the elderly.
An attempt to develop such a model system called ‘Fukushi no Mori’ was begun in 1987 in Koga City, Ibaraki Prefecture. It was not until 1993 that the land for the project was acquired and the final plans for the arrangement of facilities were drawn up. In March 1994 construction got under way.
This paper discusses the strategies for developing an integrated health, medical and welfare system in this city. The results of a number of detailed research studies undertaken by the authors are also described and discussed.

Every local government in Japan is seeking to have an integrated health, medical and welfare system to take care of an increasing number of the elderly.
An attempt to develop such a model system called ‘Fukushi no Mori’ was begun in 1987 in Koga City, Ibaraki Prefecture. It was not until 1993 that the land for the project was acquired and the final plans for the arrangement of facilities were drawn up. In March 1994 construction got under way.
This paper discusses the strategies for developing an integrated health, medical and welfare system in this city. The results of a number of detailed research studies undertaken by the authors are also described and discussed.