Microarray applicator

A microarray applicator comprising:

• a housing, the housing comprising:
• a first major surface configured to be positioned towards skin and defining a bottom of the housing;
• a second major surface opposite the first major surface and defining a top of the housing;
• a cavity extending through the first and second major surfaces;
• an interior surface defining the cavity, the interior surface comprising one or more ridges, each ridge of the one or more ridges comprising a ridge width and a ridge height, wherein the ridge height is defined by a distance between the ridge and the first major surface of the housing;
• and
• a microarray device releasably engaged with a holder, the holder located between the first and second major surfaces within the housing;
• and
• a plunger comprising:
• a top, a bottom, and one or more sides;
• a first set of one or more notches located proximate to the bottom of the plunger, each notch of the first set of one or more notches being located substantially a same distance from the bottom of the plunger, and extending a first depth into the one or more sides of the plunger such that when a first notch of the first set of one or more notches is fully engaged with a ridge of the one or more ridges of the interior surface of the housing, wherein the first notch of the first set of one or more notches comprises a profile that is substantially rotationally symmetric about an axis substantially normal to the one or more sides of the plunger adjacent to the first notch;
• releasing the first notch in a direction towards the bottom of the housing requires substantially the same force as releasing the first notch in a direction towards the top of the housing;
• and
• a second set of one or more notches located proximate to the top of the plunger, each notch of the second set of one or more notches being located substantially a same distance from the top of the plunger, and extending a second depth into the one or more sides of the plunger such that when a second notch of the second set of one or more notches is fully engaged with a ridge of the one or more ridges of the interior surface of the housing, wherein the second notch of the second set of one or more notches comprises a profile that is substantially rotationally symmetric about an axis substantially normal to one or more sides of the plunger adjacent to the second notch;
• releasing the second notch in the direction towards the bottom of the housing requires substantially the same force as releasing the second notch in the direction towards the top of the housing;
• wherein the second depth is equal to or less than the first depth;
• wherein the plunger is slidably engageable with the cavity in the housing to be moveable between a first position wherein the first set of one or more notches is engaged with the one or more ridges in the housing and the bottom of the plunger does not extend below the first major surface of the housing, and a second position wherein the second set of one or more notches is engaged with the one or more ridges in the housing and the bottom of the plunger extends below the first major surface of the housing, and wherein the holder is adapted for insertion and removal of the microarray device when the plunger is in the first position, thereby facilitating reuse of the microarray applicator.