Abstract: The present invention relates to an artificial nucleus pulposus implant that is injected minimally invasively into the nucleus cavity of the annulus fibrosus to restore the normal anatomical and physiological function of the spine in the affected disc segment. In one aspect of the invention, a device is disclosed for delivering a phase changing biomaterial to a tissue site, the device comprising a dispenser including (i) a plunger having a proximal portion and a distal portion, an inlet end and an outlet end, (ii) a dispensing actuator attached to the proximal portion of the plunger, and (iii) a cartridge adapted to be inserted into the inlet end of the plunger for containing the phase changing biomaterial in a fluid state. The dispenser may be mechanically, pneumatically or hydraulically actuated. The dispenser may further comprise a nozzle attached to the cartridge for dispensing the biomaterial to the tissue site.