Abstract: Stabilized interface systems and compositions for positioning target(s), comprising fluids, associated structural material(s) having a pore that permits passage and positioning of targets and related compositions, and a fluid phase, layer, or interface stabilized with the associated structural material. Miscible interface systems and compositions for positioning target(s) for detection comprising two or more fluid regions with different properties within a phase or layer where the fluid regions are stabilized with respect to each other using a solid or semi-solid structure or material with at least one pore that allows passage of said target(s) wherein stabilization allows mass transport of a fluid constituent via diffusion to prevail over bulk fluid motion.