[Jordan Miller], [Christopher Chen], and a whole bunch of other researchers at the department of bioengineering at U Penn have figured out a way to print 3D tissues using a 3D printer. In this case, a RepRap modified to print sugar.
Traditional means of constructing living 3D tissues face a problem – in a living body, there’s a whole bunch of vasculature sending Oxygen and nutrients to the interior cells. In vitro, these nutrients can’t get to the cells in the core of a mass of tissue. [Jordan], [Chris], et al. solved this problem by printing a three-dimensional sugar lattice. After encasing this lattice in a gel embedded with living cells, the sugar can be dissolved and the nutrients pumped through the now hollow capillaries in the gel.
If you have access to Nature, the full text article is available here. There’s also a great video showing off this technique after the break.