Gelatin's natural viscosity is relatively large due to intermolecular interactions such as hydrogen bonding and electrostatic interactions between its amino acid residues (especially amine and carboxyl groups).

Methacrylation involves attaching methacryloyl groups to primary amine groups (e.g., lysine residues).

This reduces the number of available hydrogen bonding and ionic interaction sites, weakening network formation and lowering solution viscosity. Disruption of Triple Helix or Secondary Structures Native gelatin can partially reform triple-helical structures upon cooling, increasing viscosity. Methacrylation disrupts this structural recovery by modifying amino acid residues critical for helix formation. As a result, GelMA behaves more like a random coil polymer, which flows more easily and has lower viscosity.Article Macroporous 3D printed structures for regenerative medicine ...