By BRYANNA SANTOS, age 10
3D printers can be used to print bacterial breeding colonies. These bacterial colonies help scientists understand how infections that are resistant to antibiotics spread. Scientists also aim to use embryonic stem cells, cells taken from fertilized human eggs, to print human organs for people who need organ transplants. 3D printing works much like an ordinary printer, but instead of printing ink in one flat sheet, a 3D printer releases material in layers to form a three-dimensional object. This equipment is expensive, so researchers are trying to create alternatives that are less costly.