A versatile GelMA composite hydrogel: Designing principles, delivery forms and biomedical applications

Gelatin methacryloyl (GelMA), a kind of modified biomaterials with adjustable degradability from gelatin, can composite with various composite materials and therapeutic substances including cells through various physiochemical direct/indirect interactions to achieve treatment effect. Furthermore, owing to that the GelMA possesses photocrosslinking ability and excellent rheology properties, GelMA itself and its composite materials have the potential to be manufactured to function in diversified forms with 2D or 3D structures as required, such as thin films, microswimmers, biomimetic scaffolds, etc. Combined with the excellent biocompatibility from gelatin, GelMA composite hydrogels have been widely applied in biomedical applications. Unlike published reviews concentrating on a specific application fields or construction strategies of GelMA, this review summarized the multiscale construction strategies and available forms of GelMA complex hydrogel step by step based on its excellent physical and chemical properties. These strategies could be integrated to perform more desirable effects. In the end, the relevant biomedical applications in combination with the repair requirements of different tissues are briefly discussed. This systematic review can provide assistance for the rational application of GelMA in the field of biomedical.