This seems like a logical next step for tissue printing technologies: "researchers have rigged up a device that can spray skin cells directly onto burn victims, quickly protecting and healing their wounds as an alternative to skin grafts. They have mounted the device, which has so far only been tested on mice, in a frame that can be wheeled over a patient in a hospital bed. ... A laser can take a reading of the wound's size and shape so that a layer of healing skin cells can be precisely applied. ... We literally print the cells directly onto the wound. We can put specific cells where they need to go. ... [Researchers] dissolved human skin cells from pieces of skin, separating and purifying the various cell types such as fibroblasts and keratinocytes. They put them in a nutritious solution to make them multiply and then used a system similar to a multicolor office inkjet printer to apply first a layer of fibroblasts and then a layer of keratinocytes, which form the protective outer layer of skin. ... The sprayed cells also incorporated themselves into surrounding skin, hair follicles and sebaceous glands, probably because immature cells called stem cells were mixed in with the sprayed cells."