A team from UCLA has 3D-printed microparticles that may be suitable for medical applications:
Bioengineers from the UCLA Henry Samueli School of Engineering and Applied Science have developed a new method of 3-D printing that allows production of complex micro-scale objects smaller than the width of a human hair. The technique, using patterned ultraviolet light and a custom-shaped flow of polymer material, creates 3-D objects that can be first designed with software and could be used in a variety of biomedical and industrial applications. The research was published online in the journal Advanced Materials.
The authors suggest that producing 3-D shapes at the micro scale could be useful for designing custom biomaterials such as interlocking particles that self-assemble to help tissue regenerate, or for industrial applications such as creating new coatings and paints with unique light-reactive properties.
[...] To make smaller custom objects with folds, holes and other precise features, the UCLA team developed a new technique called optical transient liquid modeling. It uses a series of microfluidic and optical technologies, including a technique previously developed by Di Carlo's research group that simplifies designing the shape of fluid flows.
First, two different types of fluids are combined in a series of tiny pillars that control the shape of the merged fluids. One fluid is a liquid polymer that is the precursor material for the object. The other essentially acts as a liquid mold for the polymer stream. The arrangement of the pillars determines how the two flows mix and intertwine. The researchers used software that they previously developed to rapidly predict what shape will be produced by altering the pillars' location and sequence. It can be downloaded for free here.
When the flow of materials is stopped rapidly, an outlined pattern of ultraviolet light — somewhat like a cookie cutter — slices into the precursor stream. So the object is shaped first by the stream, then again by UV light. The UCLA researchers have reached printing speeds of nearly one object every five seconds.
[...] The objects the team has produced are about 100–500 micrometers in size, with features as small as 10–15 micrometers. With this method, they have produced objects composed of organic materials as well as particles whose movements and position could be precisely controlled by magnetism.
Via NextBigFuture.
Rapid Software-Based Design and Optical Transient Liquid Molding of Microparticles [abstract]
