The latest issue of the Proceedings of the National Academy of Sciences may not be on your coffee table, but it does contain within its pages a fascinating new development in materials technology for 3D printing. A team of researchers from Harvard university have contributed two new technologies that will change the way that materials can be used in 3D printing. Specifically, these two developments address the difficulty of printing with different materials. One innovation is the creation of an active mixing system that mixes two fluids together using an impeller in order to print with a makeup that can be changed as printing proceeds. The other is a novel new printhead that can switch back and forth between materials using a single nozzle. Check out more details in the full story: http://3dprint.com/96973/expand-3d-printing-materials/