A device and method for delivering a high viscosity composition is described. The composition includes a bioactive agent for delivery to a subject in need thereof. The method delivers the bioactive agent at a high bioavailability and with little loss of agent to the natural defense mechanisms of the body. The device includes one or more microneedles with structures fabricated on a surface of the microneedles to form a nanotopography. A random or non-random pattern of structures may be fabricated such as a complex pattern including structures of differing sizes and/or shapes.
