Disclosed systems relate to medical devices for delivering fluid. In an example, a device includes a catheter having a distal end and a gasket movably positioned within a lumen of the catheter. The gasket includes a distal end having a first diameter, a proximal end having a second diameter that is greater than the first diameter, and a body connecting the distal end and the proximal end. The device also includes a nozzle positioned on the distal end of the catheter.

The present invention discloses a magnetic force-driven apparatus designed to perform injection operations by being installed with a vial. The magnetic force-driven injection apparatus includes a sleeve, a power supply unit, a first actuator, a second actuator, and a magnetic force generating unit. The magnetic force-generating unit is selectively coupled with either the first actuator or the second actuator. When the magnetic force-generating unit generates a magnetic force, it generates either a magnetic attraction or a magnetic repulsion between the first actuator and the second actuator, so the second actuator is driven either toward the vial closely to activate the injection or farther away from the vial after the injection.