E-Mail IMAGE: Top view of two collagen hydrogels that researchers decorated with immobilized mCherry proteins, which glow red under fluorescent light. The team scanned near-infrared lasers in the shapes of a monster... view more Credit: Batalov et al., PNAS, 2021 Imagine going to a surgeon to have a diseased or injured organ switched out for a fully functional, laboratory-grown replacement. This remains science fiction and not reality because researchers today struggle to organize cells into the complex 3D arrangements that our bodies can master on their own. There are two major hurdles to overcome on the road to laboratory-grown organs and tissues. The first is to use a biologically compatible 3D scaffold in which cells can grow. The second is to decorate that scaffold with biochemical messages in the correct configuration to trigger the formation of the desired organ or tissue.