Polymeric microstructures and systems and methods for making same

A patch comprising:

• a backing layer;
• and
• a plurality of polymeric microneedles in contact with the backing layer, wherein each microneedle comprises a lattice microstructure having one or more lattice cell units;
• wherein the microneedle comprises a gradient in the lattice cell units such that the density of lattice cell units increases across a longitudinal axis of the microneedle.

A method of making a polymeric microneedle comprising a lattice microstructure having one or more lattice cell units, the method comprising:

• a) irradiating a polymerizable composition positioned between a build elevator and a build surface to generate a polymerizable composition comprising a first polymerized region of the polymerizable composition in contact with the build elevator and a first non-polymerized region of the polymerizable composition in contact with the build surface;
• b) displacing the build elevator away from the build surface;
• c) irradiating the first non-polymerized region of the polymerizable composition to generate a second polymerized region of the polymerizable composition in contact with the first polymerized region and a second non-polymerized region in contact with the build surface;
• and
• d) repeating steps a)-c) in a manner sufficient to generate a microneedle comprising a lattice microstructure.

A system for making a polymeric microneedle comprising a lattice microstructure having one or more lattice cell units, the system comprising:

• a micro-digital light projection system comprising:
• a light beam generator component;
• and
• a light projection monitoring component;
• a liquid interface polymerization module comprising a build elevator and a build surface configured for generating the microneedle from a polymerizable composition positioned therebetween;
• and
• a processor comprising memory operably coupled to the processor wherein the memory comprises instructions stored thereon, which when executed by the processor, cause the processor to:
• a) irradiate a polymerizable composition positioned between a build elevator and a build surface to generate a polymerizable composition comprising a first polymerized region of the polymerizable composition in contact with the build elevator and a first non-polymerized region of the polymerizable composition in contact with the build surface;
• b) displace the build elevator away from the build surface;
• c) irradiate the first non-polymerized region of the polymerizable composition to generate a second polymerized region of the polymerizable composition in contact with the first polymerized region and a second non-polymerized region in contact with the build surface;
• and
• d) repeat steps a)-c) in a manner sufficient to generate the polymeric microneedle comprising a lattice microstructure.