Question

Most organ printing techniques seem to use a structural element for newly created cells to anchor themselves to, be it a biocompatible plastic or some natural material. Naively, I would assume that organs can be generated just the same as they are in an embryo, so why is scaffolding necessary? Here are my guesses:

The time taken to grow an organ to an adult size this way would take too long to be practical
Making the necessary germlines to emulate those formed in gastrulation is to difficult
Organs grown this way collapse into themselves without the exact environment present in an embryo (the pressure in an embryo could be necessary, or the formation of all organs concurrently allows each particular organ to maintain a solid boundary between itself and its neighbors)
Without scaffolding, organs printed in vitro would not generate the auxiliary structures necessary to be useful (nerve endings, blood vessel, etc.)

Answer 1

Scaffolding is vital in organ printing because it provides structural support, guides cell distribution and organization, and influences cell fate, which are all crucial factors for generating functional in vitro organs.

Step-by-step explanation:

The necessity of scaffolding in organ printing is related to the complex process of organ development, known as organogenesis, which involves the differentiation of cells into specific tissues and structures. In natural embryonic development, organs develop from three germ layers in a highly controlled environment with specific genetic expression and cellular signaling. In contrast, artificial in vitro organ growth requires scaffolding because it provides the necessary structural support, helps in the organization and distribution of cells, and facilitates the formation of complex tissue architectures including blood vessels and nerves. These structures are essential for the function and survival of printed organs, as they are for natural organs.

During natural embryonic development, structures such as bones develop from a cartilage template through processes like endochondral ossification. Similarly, organ printing uses scaffolds as a template to guide the development and shape of the organ being printed. Moreover, the spatial distribution of cells and their exposure to physical forces can influence cell fate and function, highlighting the importance of scaffolding in providing the appropriate physical cues for cells to differentiate and organize correctly.