Engineers at the University of California, San Diego have developed a new process that can fabricate microscale 3D sturctures out of soft biocompatible hydrogels. The aim of this new process is to develop better systems for growing and studying cells, including stem cells in laboratory conditions. Going forward, the long term strategy is to develop printing technology for biological tissues for regenerative medicine. In practical terms this technology could be used for offering treatment to heart attack patients, for example, by offering tissue from the printer to replace the damaged areas.
Current fabrication techniques such as photolithography and micro-contact printing are limited to generating simple geometries or 2D patterns. Professor Shaochen Chen from the Nano engineering laboratory has developed a new bio-fabrication technology called dynamic optical projection stereolithography (DOPsL). Stereolithography is best known for its ability to print typically larger objects such as tools and car parts. The difference, says Chen, 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, it is useless in regenerative medicine.
With DOPsL, Chen’s team achieved more complex geometries that are more commonly found in nature such as flowers, spirals and hemispheres. In comparison, other current 3D printing techniques such as two-photon photopolymerization can take hours to fabricate a 3D part. The biofabrication technique 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 photo-induced solidification process forms one layer of solid structure at a time, but in a continuous fashion.
The technology is part of a new biofabrication technology that Chen is developing under a four-year, $1.5 million grant from the National Institutes of Health. In March, the Obama administration 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.