Figure 2.

Commonly used strategies for organ decellularization and acceptance criteria for decellularized extracellular matrix (dECM). A number of enzymatic, physical, and chemical agents can be used to remove cells from organs and to obtain purified extracellular matrix (ECM), which can be used as a starting material for bioink formulation. Commonly used acceptance criteria to establish full decellularization of the tissue are the absence of visible nuclei in sections fluorescently stained for nucleic acid detection (DAPI or similar); the presence of less than 50 ng of double-stranded DNA (dsDNA) per mg dry weight, with fragments below 200 base pairs (bp); and the absence of the alpha-Gal epitope (Galalpha1–3Galbeta1-(3)4GlcNAc-R) of nonprimate mammals.