I think that Shelley's use of the the title, "The Modern Prometheus" was designed to be a modern interpretation of the creation myth. Prometheus was the Greek Titan who created man and also taught him the use of fire and how to trick the gods. When Zeus punishes humanity for their deception, he condemns Prometheus, who accepts his punishment with an honorable sense of responsibility. This particular example of creation shows a love, respect, responsibility, and care from the creator to the created. Shelley wants to invert this in her depiction of the relationship between creator and created in Frankenstein. The same elements of wanting to create something (what she will call a "hideous progeny") are present in both the ancient and modern versions of Prometheus. Instilling the creature with abnormal size and strength is akin to Prometheus giving fire and the ability to trick to gods to mankind. However, in the ancient story, the creator does not abandon the created- both suffer together. In the modern version, Victor is horrified with his creation and he abandons it entirely, and then claims to not have any responsibility for it or its actions. This modern Prometheus shows the lack of connection between a creator and what is created. In some respects, the paternally loyal vision of the ancient world has been supplanted by a modern version where siblings abandon one another and parents abandon children, with frightening regularity. The modern version of creation is, thus, one steeped in a tragic condition.
To the above answer, Victor does take responsibility for the monster's action. He constantly blames himself when it murders... try to reolve that contradiction please.