Synthesis and Application of Fish Gelatin for Hydrogels/Composite Hydrogels: A Review

Hydrogels are one of the biopolymers that have been applied and have excellent potential to be developed as a raw material in future food technology, biomedicine, and three-dimensional (3D) bioprinting. Even stigmatized that hydrogels are the only source of bioink for 3D bioprinting. Among natural sources, protein-based hydrogels have advantages in the aspects of biocompatibility, biodegradability, tunability, molecular binding ability, and bioactive properties. Gelatin is a natural protein-based biopolymer that offers potential. Besides its advantages as a natural protein-based hydrogel, gelatin is also inexpensive, usually extracted from processing by-products such as skins and bones. Studies also mentioned that gelatin has the tripeptide motif that promotes cell attachment for subsequent cellular processes, like migration, differentiation, and proliferation. However, most gelatin is derived from mammalian sources, while these sources are limited considering socio-religion, cultural, health aspects. Fish gelatin is the most potential source for alternative gelatin. They have uniqueness and viscosity for bio-fabrication and injectable hydrogels. Therefore, this paper will review the hydrogels based on fish gelatin studied in recent years and the last decade. Here also described the stages in the fabrication of fish gelatin hydrogels/hydrogel composites with different co-polymers, composite materials, polymerization methods, and future intended use of obtained fish gelatin hydrogels/composites.