The use of inkjet printing in tissue engineering research continues to expand, as reported at ScienceDaily: scientists have shown "that producing cardiac tissue with off-the-shelf inkjet technology can be improved significantly with precise cell placement. ... Since Boland's discovery in 2004, 'printing' tissue using 3-D printers has focused on printing materials for hard tissue applications, such as in the jawbone. The [study] focused on precise placement of cells, which is essential to achieving function in soft tissue, such as the heart. In this study, live, beating heart cells were achieved more efficiently. The breakthrough with this technology is that cells now can be precision-placed virtually instantaneously with the materials that make up a scaffold to hold the cells in place ... Precision placement of the cells is achieved by filling an empty inkjet cartridge with a hydrogel solution (a material that has properties similar to tissue) and another inkjet cartridge with cells. The printing is accomplished much in the way that color photographs are made, activating alternatively the hydrogel and cell nozzles."