conditions, and reduce necrosis. In this same time frame, researchers started to analyze the regenerative capacity of dissociated cells. As early as 1907, Wilson (1907) showed that sponges could be broken down to single cells that were able to reassociate into tissue-like structures. The same was true for Coelenterates (De Morgan and Drew, 1914) and amphibian embryonic cells (Holtfreter, 1948). Moscona, in the early 1950s, established a method to enzymatically digest limb and kidney rudiments of early chick embryos. He cultured these cells in suspension and showed that they were able to reaggregate and reestablish the structural pattern of their tissue of origin (Moscona and Moscona, 1952; Moscona, 1959). Thus, by the middle of the twentieth century, researchers were working toward generating organs from dissociated cells, albeit mainly in suspension. Knowing that collagen was a universal component of connective tissues, as early as 1932, Huzella (1932) and collaborators had experimented culturing cells on fibrous collagen, a condition that is considered a 2D culture. However, it was in 1956 that Robert Ehrmann and George Gey published a method to reconstitute collagen extracted from rat-tail tendons as a transparent gel (Ehrmann and Gey, 1956). In their original paper, 29 cells lines and
