A device that may be placed on a biological barrier can be used to perforate the biological barrier for a variety of purposes such as cosmetic, scar treatment or for the delivery of active agents. A flexible substrate has a first side and a second opposing side and a plurality of micro-penetrator arrangements each comprising a head and a first and second projection, for penetrating a biological barrier, extending from the head. The first and second projection at least partially extend through the flexible substrate towards the first side. The head comprises an elongate arm for spacing apart the first and second projections. A force is applied to the second side causing flexing of the flexible substrate and pushing the projections into communication with a biological barrier.