Minimally invasive therapeutic fluid delivery devices, systems, and methods are disclosed. In some embodiments, the devices include at least a flexible elongate member with a chamber situated in the distal portion thereof, the chamber having an inlet and an outlet and a piezoelectric actuator that alters a volume of the chamber to eject a portion of the therapeutic fluid. In one embodiment, the device includes an array of piezoelectrically actuatable chambers that can eject a droplet of a drug orthogonally to the length of the flexible elongate member. In another embodiment, the device includes a piezoelectrically actuatable chamber that ejects along the length of the flexible elongate member.
