For the purposes of drug toxicology screening, it is much more useful to test gene expression of in vitro cells grown in 3D than 2D, since the gene expression of the 3D spheroids will more closely resemble gene expression in vivo. Lastly, 3D cell cultures have greater stability and longer lifespans than cell cultures in 2D. This means that they are more suitable for long-term studies and for demonstrating long-term effects of the drug. 3D environments also allow the cells to grow undisturbed. In 2D, the cells must undergo regular trypsinization to provide them with sufficient nutrients for normal cell growth. 3D spheroids have been cultured in a lab setting for up to 302 days while still maintaining healthy, non-cancerous growth.
