It’s a mystery how objects/items can gain df powers and transform into animal and have a life, like Lasoo the gun of Mr 4 transforming into a cannon dog and Funkfreed the sword of Spanda that can turn into elephant sword.
Vegapunk scientific research successfully devised a method on how inanimate objects like gun and swords obtain a devil fruit and I have a guess on how he did it.
If we analyse the objects that have df powers we will see their one similarity which is the “metal/iron”, Lasoo (Gun) and Funkfreed (sword) is both made of metal/iron, so how metal relates to obtain the df power for inanimate object? Metal/iron might have a big role for the inanimate objects to gain df power.
I believe Lasoo and Funkfreed didn’t eat the devil fruits, they just absorb it.
Maybe one part of the method that used by Vegapunk is the “juicing.” Juice is naturally contained in fruits and juice is prepared by mechanically squeezing fruit flesh without application of heat and solvent. So I guess Vegapunk invented a machine that can turn the devil fruit into liquid so that he can extract it with inanimate objects that can absorb liquid and one object that can absorb liquid is metal/iron, maybe Vegapunk used a special iron like the Liquore or maybe he knows how to create Liquore.
But, extracting devil fruit juice into inanimate object is not enough to make the research of Vegapunk successful to give life to the object, unlike the paramecia and logia, Zoan devil fruits is he only df that have the ability to give life to the objects because of its ability to transform the user into animal.
I hope this short theory make a little bit sense.
*Theory by Fire_Fist_Recca