A method or apparatus for creating a three-dimensional tissue construct of a desired shape for repair or replacement of a portion of an organism. The method may comprise injecting at least one biomaterial in a three-dimensional pattern into a first material such that the at least one biomaterial is held in the desired shape of the tissue construct by the first material. The apparatus may comprise an injector configured to inject at least one biomaterial in a three-dimensional pattern into a first material such that the at least one biomaterial is held in the desired shape of the tissue construct by the first material. The first material may comprise a yield stress material, which may be a material exhibiting Herschel-Bulkley behavior. The tissue construct may have a smallest feature size of ten micrometers or less.