Materials that allow ions to flow

[Hydro-Cell]

i have seen that salt bridges are able to do this, the simplest way being filter paper soaked in a salt solution, i.e sodium hydroxide.
this bridge then allows 2 cells to be connected together even though there in seperate containers,

i am just curious, does anyone know of a solid material that can be machined that does the same thing.

i have seen people make a human salt bridge, by putting there index and middle finger into each container, so this leads me to think there may be some other material apart from filter papers.

the tube salt bridge is no good for my application.

any help is appreciated