3D printing has emerged as a powerful tool for fabricating living materials, enabling the creation of complex structures with precise control over their composition and properties. Researchers have developed a method for 3D printing bacteria-alginate bioinks, which exploits simple alginate chemistry for printing onto calcium-chloride surfaces, resulting in the formation of bacteria-encapsulating hydrogels with varying geometries. This technology allows for the printing of engineered bacteria to produce inducible biofilms, leading to the formation of multilayered three-dimensional structures.