Figure 8. (a) Temporal hydrogel that can be used for human umbilical cord stem-cell via a lipase-catalyzed reaction network. Copyright (2015) American Chemical Society. (b) a fatty acid-based system that can transiently gelate by the drive of dimethylaminomethyl ferrocene. Copyright (2019) Royal Society of Chemistry. (c) a dithionite-driven “gel-sol-gel” transient cycle. Copyright (2020) American Chemical Society. (d) a thiuram disulfides-driven “gel-sol-gel” transient cycle. Copyright (2022) American Chemical Society.