April Flowers for redOrbit.com – Your Universe Online
Nanoengineers at the University of California, San Diego have created a new technology that has far-reaching implications for regenerative medicine. The results of the project have been reported in Advanced Materials.
The team has been able to fabricate, in seconds, microscale three-dimensional (3D) structures out of soft biocompatible hydrogels. This could lead to better systems for growing and studying cells, including stem cells, in the laboratory. In the long-term, the goal is to be able to print biological tissues for regenerative medicine. For example, repairing the damage caused by a heart attack by replacing it with tissue from a printer.
Professor Shaochen Chen developed this new biofabrication technology, called dynamic optical projection stereolithography (DOPsL). Current fabrication techniques, such as photolithography and micro-contact printing, are limited to generating simple geometries or 2D patterns. Stereolithography is best known for its ability to print large objects such as tools and car parts.
The difference between earlier stereolithography and DOPsL, Chen says, is in the micro- and nanoscale resolution required to print tissues that mimic nature´s fine-grained details, including blood vessels, which are essential for distributing nutrients and oxygen throughout the body. Without the ability to print vasculature, an engineered liver or kidney, for example, is useless in regenerative medicine. With DOPsL, Chen´s team was able to achieve more complex geometries common in nature such as flowers, spirals and hemispheres. Other current 3D fabrication techniques, such as two-photon photopolymerization, can take hours to fabricate a 3D part.
The system uses a computer projection system and precisely controlled micromirrors to shine light on a selected area of a solution containing photo-sensitive biopolymers and cells. This begins the solidification process, which forms one layer of solid structure at a time, but in a continuous fashion. The Obama administration in March launched a $1 billion investment in advanced manufacturing technologies, including creating the National Additive Manufacturing Innovation Institute with $30 million in federal funding to focus on 3D printing. The term “additive manufacturing” refers to the way 3D structures are built layering very thin materials.
The development of this new technology is part of a grant that Chen received from the National Institutes of Health (NIH). Chen’s research group focuses on fabrication of nanostructured biomaterials and nanophotonics for biomedical engineering.