Apparatus and method for puncturing the epidermis with controlled fluid delivery

An apparatus for puncturing an epidermis with controlled fluid delivery, the apparatus comprising a needle cartridge attached to and interfacing with an actuating device, the cartridge comprising:

• a housing assembly forming a fluid cavity and comprising a first aperture at a tip of the housing assembly and a second aperture opposite the first aperture;
• a needle group assembly comprising a needle, wherein:
• the needle group assembly is configured to move in a reciprocating motion relative to the housing assembly along an axis from the first aperture to the second aperture,
• the needle is configured to fully retract into the fluid cavity through the first aperture during the reciprocating motion, and
• the needle is configured to extend into a patient's skin at a repeatable depth by resting the tip of the housing assembly on the patient's skin during the reciprocating motion;
• a needle group housing that forms a needle group cavity and separates the fluid cavity from the needle group cavity, wherein:
• the needle group housing comprises a fourth aperture through which the needle passes,
• the needle is configured to fully retract into the needle group housing through the fourth aperture during the reciprocating motion,
• and the needle group housing surrounding the fourth aperture is configured to remove dermal debris from the needle during the reciprocating motion;
• and
• a fluid port integrated with the housing assembly and comprising a third aperture.