Abstract: A fluid-delivery device includes an array of needles. The needle can deposit a hollow and/or porous tube into a tissue of a subject, and the porous tube can contain one or more fluid agents. The hollow and/or porous tube can control the rate at which the agents diffuse into the tissue. The device can simultaneously deliver a plurality of porous tubes along parallel axes in a tissue in vivo. If thereafter resected, the tissue can be sectioned for evaluation of an effect of each agent on the tissue; based on the evaluation, candidate agents or subjects can be selected or deselected for clinical trials or therapy.