We all know that chopper was able to extend the capability of his devil using his rumble ball. But I wonder if other DF users can also use this rumble ball.
While it doesn't look like anyone else has tried the rumble ball that Chopper created yet, modifying your devil fruit power through science is possible.
The One Piece Wikia on the rumble ball has it written:
Through his development of the Rumble Ball, Chopper is the first Devil Fruit user to artificially augment his Devil Fruit powers. However Chopper is not the only one to do so, as Caesar Clown (by his own admission) used his chemical and scientific expertise to artificially augment the Gasu Gasu no Mi to grant himself new offensive abilities.
While the Wikia also implies that the Rumble Ball can enhance any Zoan type, I have not seen this evidenced by anyone else's use in canon sources.