Dr. Vegapunk is the leading researcher on Devil Fruits and how they work. The Straw Hats' encounter with this scientist should be quite informative.
One Piece Chapter 1061, "Future Island Egghead," established that the Straw Hat Pirates would be visiting the island of the Marines' head scientist Dr. Vegapunk. With this arc, there's a chance for all sorts of new story elements to be expanded upon, especially all of Vegapunk's inventions. However, one thing that might not immediately come to mind regarding Vegapunk is their knowledge of Devil Fruits.
There are a lot of things fans don't know about Devil Fruits. However, it was suggested a long time ago that Vegapunk may have these kinds of answers. If they do, then the Egghead Arc will be the ideal place to answer many decades-old questions about one of One Piece's most integral plot points.
Why would Vegapunk Know About Devil Fruits?
Dr. Vegapunk in One Piece.
Vegapunk's knowledge of Devil Fruits was confirmed in an SBS from Volume 48 of the manga. Originally, a fan asked a question about a potential discrepancy in the story's explanation of Devil Fruits. According to Usopp, the same power can't exist twice, but that wouldn't explain how Luffy's Gum-Gum Fruit was already cataloged in Chapter 1. If there was prior knowledge of the Fruit, then someone else must have eaten it before.
Eiichiro Oda was gracious enough to answer the fan's question. He clarified that no two people could have the same Devil Fruit power at the same time; this falls in line with everything that's been shown in the story since then. As for the details, Oda said that a more formal explanation of Devil Fruits would eventually be given by a certain professor.
This professor would later turn out to be Vegapunk. The doctor had been conducting research on the Devil Fuits' properties and even learned how to replicate them; they recreated KaidÅ's Devil Fruit with moderate success and even managed to replicate the effects of Admiral Kizaru's Glint-Glint Fruit for the Pacifistas' lasers. Their knowledge of Devil Fruits may be considered incomplete by some, but it's far more than most people know.
What Questions Still Need to Be Answered About Devil Fruits?
Devil Fruits from One Piece.
Even though the manga has been running for 1060 chapters now, Devil Fruits largely remain an enigma. Some big questions include how they came into the One Piece world, how long they've been around, why they make it so that their eaters can't swim, or why it's normally impossible to eat more than one of them. Some characters have fittingly attributed the Fruits' properties to the power of a devil, but there's probably much more to the story than that.
It would also be nice to understand how Blackbeard knows so much about Devil Fruits himself. He's uncovered enough of the mystery that he knows how to transfer Devil Fruit powers and even how to hold more than one of them. Learning at least this much from Vegapunk would give the Straw Hats a much better idea of what they're going up against, especially Luffy and his fellow Fruit-eaters. This would also give the audience a better idea of what the stakes will be when this confrontation finally happens.
Ideally, the Straw Hats, or at least the audience, should have some new knowledge of what Devil Fruits are by the end of the Egghead Arc. Considering how One Piece is in its final saga, it's about time this grand mystery of the narrative gets resolved. If Vegapunk isn't the professor with the answers, then nobody is.