Is cooper wire a solution?

COPPER wire isn't really a scientific tool. It's more like a necessary part of many electric-powered/electronic scientific tools.

because its the best for electrical conductivity

No. You start with copper, and when you are finished it is still copper, so there is no chemical change. It's a physical change. You changed the shape and moved some atoms around.

Metallic

Water makes a poor conductor compared to copper.As demonstrated here:http://www.ehow.com/video_4936269_electric-circuit-experiments-water-battery.htmlWith the addition of electrolytes, water can move...