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Figure 1. (A) Schematic diagram of processing collagen to gelatin and the mechanism of sol-gel transition of gelatin hydrogel upon heating and cooling^[12]. Reprinted with permission. Copyright 2019, Multidisciplinary Digital Publishing Institute; (B) Chemical structure and properties of gelatin^[13]. Reprinted with permission. Copyright 2021, Wiley-VCH; (C) Fabrication; and (D) photos and tensile stress-strain curves of high-strength gelatin-ammonium sulfate hydrogels via the Hofmeister effect^[19]. Reprinted with permission. Copyright 2018, WILEY-VCH; (E) Schematic of formation, structure, and non-covalent interactions in gelatin organohydrogels; and (F) Photos showing the high mechanical performances of gelatin organohydrogels^[22]. Reprinted with permission. Copyright 2019, ACS Publications.