Article with hollow microneedles and method of making

An article, comprising:

• a substrate having first side and second side opposite the first side,
• wherein the first side comprises a first major surface having at least one microneedle extending therefrom, the at least one microneedle comprising a body and a first opening;
• wherein the second side comprises a second major surface having a second opening;
• and
• a channel extending from the first opening to the second opening, the channel having a first channel segment extending from the first opening, a second channel segment extending into the substrate from the second opening, and a third channel segment extending between the first channel segment and the second channel segment;
• wherein the first channel segment has a first interior surface topology, the second channel segment has a second interior surface topology, and the third channel segment has a third interior surface topology;
• wherein the third interior surface topology is optically distinguishable from the first interior surface topology.

A method, comprising:

• molding a material to form a substrate comprising:
• a first side comprising a first major surface that defines a base from which a plurality of microneedles extend;
• wherein each microneedle of the plurality of microneedles comprises a body, a tip and a first cavity extending into the body;
• and
• a second side opposite the first side, the second side having a second major surface that comprises a plurality of second cavities, each second cavity extending into a body of one of the plurality of microneedles;
• wherein a straight line passing through the substrate can enter the substrate at a first point in the first cavity and exit the substrate at a second point in the second cavity;
• affixing the substrate;
• registering a location of at least one microneedle;
• and
• forming a hollow channel through one of the plurality of microneedles, wherein forming a hollow channel comprises forming a channel between the first cavity and the second cavity.

A method, comprising:

• molding a material to form a substrate comprising:
• a first major surface comprising a plurality of microneedles extending there from, each microneedle comprising a first cavity;
• and
• a second major surface opposite the first major surface, the second major surface comprising a plurality of second cavities;
• wherein molding the material comprises forming a thinned region between the first cavity and the second cavity;
• wherein a straight line passing through the material can enter the substrate at a first point in the second cavity and exit the substrate at a second point in the first cavity;
• and
• directing electromagnetic radiation toward the first major surface and using an imaging device to capture an image of the second major surface or directing electromagnetic radiation toward the second major surface and using an imaging device to capture an image of the first major surface;
• and
• using the image to process two or more microneedles of the plurality of microneedles.