An implantable electrode adapted to be injected into a body for electrical interfacing with a target within said body, said implantable electrode comprising a mixture of solid conductive elements and a biocompatible non-conductive carrier, said biocompatible non-conductive carrier is configured to transition from a liquid phase to a solid phase, wherein said mixture is adapted to be injected into the body to the target through at least one needle such that the biocompatible non-conductive carrier of said mixture is in the liquid phase during the injection of the mixture into the body, and wherein the biocompatible non-conductive carrier of said mixture is adapted to transition to the solid phase by a phase transition and cured within the body such that said mixture forms said implantable electrode that is conformable to a three-dimensional shape of contours of the target and adapted to conduct electricity through the conductive elements to the target within the body.