A system and method for delivering fluid into a flexible biological barrier employs a microneedle structure wherein a final position of microneedles inserted into the biological barrier is generally sideways projecting from the delivery configuration instead of the conventional downwards projecting arrangement. The microneedles project from a relief surface which is distinct from a primary biological-barrier contact region of the delivery configuration, and is typically angled upwards away from the biological barrier. During insertion, the contact region is brought into contact with the biological barrier and moved parallel to the surface of the flexible biological barrier so as to generate a boundary between a stretched portion and a non-stretched portion of the barrier. Typically concurrently with this motion, the microneedles penetrate into the flexible biological barrier such that, at the end of the motion, the microneedles extend into the flexible biological barrier from the boundary region in a direction towards the non-stretched portion. Fluid is then injected through the bores of the hollow microneedles towards non-stretched portion.