An Angel's Space-Time Boat ― The Legend of Leonardo da Vinci

(from ebookjapan):

Leiji Matsumoto, a giant star of the SF manga world, takes on the enigmatic life of the genius Leonardo da Vinci! Centuries in the future. The great galactic system in which human beings live has encountered a "collapsed section" of the universe. If it slips and falls, it will be swallowed into the "darkness of nothingness" and all will end...

Only 30 years remain before the end of the world! The only person who can save the world is not Einstein, Curie, or von Braun, but the genius Leonardo da Vinci! In the summer of 1452, a project to regenerate "him" from the blood sucked by a "mosquito" flying over the cold village of Vinci is about to be carried out under the direction of Professor Minami.

Mamia Luna Hotaruko (Keiko, the Japanese word for firefly), who opposes Professor Minami's idea, destroys the Replicator Pandora just before the project is to be carried out, and travels to the time of Leonardo da Vinci's life in a time cruiser. She says she will learn all about it by Leonardo's side and return to the future once more...