Gelatin methacryloyl (GelMA) hydrogels have been widely used in biomedical applications due to their suitable biological properties and tunable physical characteristics. These hydrogels closely resemble the properties of the native extracellular matrix (ECM) due to the presence of cell-attaching and matrix metalloproteinase (MMP) responsive peptide motifs, which allow cells to proliferate and spread in GelMA-based scaffolds. GelMA is versatile and can be crosslinked when exposed to light irradiation to form hydrogels with tunable mechanical properties that mimic the native ECM. It can also be microfabricated using various methodologies, including micromolding, photomasking, bioprinting, self-assembly, and microfluidic techniques, to generate constructs with controlled architectures. Hybrid hydrogel systems can be formed by mixing GelMA with nanoparticles such as carbon nanotubes and graphene oxide, and other polymers to form networks with desired combined properties for specific biological applications. Recent research has demonstrated the proficiency of GelMA-based hydrogels in various applications, including tissue engineering, fundamental single-cell research, cell signaling, drug and gene delivery, and biosensing. GelMA hydrogels are also used in microfabrication to create patterns, morphologies, and 3D structures, providing ideal platforms to control cellular behaviors, study cell-biomaterial interactions, and engineer tissues. The synthesis of GelMA involves the reaction of gelatin with methacrylic anhydride in phosphate buffer at 50°C, introducing methacryloyl substitution groups on the reactive amine and hydroxyl groups of the amino acid residues. The degree of methacryloyl substitution can be adjusted to tune the mechanical properties of the resulting hydrogels. Photocrosslinking of the product GelMA can be conducted using a water-soluble initiator under UV light. The physical properties of GelMA hydrogels, such as porosity, compressive modulus, and water swelling, as well as cell response parameters, are key to determining their suitability for different tissue engineering applications. GelMA hydrogels can be subjected to cryogenic treatments to generate porous scaffolds with controlled pore sizes and porosity. The microfabrication of GelMA hydrogels has been explored using various techniques, including photopatterning, micromolding, self-assembly, and microfluidics, to create complex architectures and control cell-material interactions. These techniques have enabled the fabrication of 3D microgels, cell-laden constructs, and vascularized tissues. Bioprinting has also been used to generate cell-laden constructs with controlled architectures for tissue engineering applications. Hybrid hydrogels based on GelMA have been developed to enhance the mechanical properties of GelMA hydrogels, which are suitable scaffolds for cell growth. These hybrid hydrogels have been used to improve the mechanical strength and electrical conductivity of GelMA hydroGelatin methacryloyl (GelMA) hydrogels have been widely used in biomedical applications due to their suitable biological properties and tunable physical characteristics. These hydrogels closely resemble the properties of the native extracellular matrix (ECM) due to the presence of cell-attaching and matrix metalloproteinase (MMP) responsive peptide motifs, which allow cells to proliferate and spread in GelMA-based scaffolds. GelMA is versatile and can be crosslinked when exposed to light irradiation to form hydrogels with tunable mechanical properties that mimic the native ECM. It can also be microfabricated using various methodologies, including micromolding, photomasking, bioprinting, self-assembly, and microfluidic techniques, to generate constructs with controlled architectures. Hybrid hydrogel systems can be formed by mixing GelMA with nanoparticles such as carbon nanotubes and graphene oxide, and other polymers to form networks with desired combined properties for specific biological applications. Recent research has demonstrated the proficiency of GelMA-based hydrogels in various applications, including tissue engineering, fundamental single-cell research, cell signaling, drug and gene delivery, and biosensing. GelMA hydrogels are also used in microfabrication to create patterns, morphologies, and 3D structures, providing ideal platforms to control cellular behaviors, study cell-biomaterial interactions, and engineer tissues. The synthesis of GelMA involves the reaction of gelatin with methacrylic anhydride in phosphate buffer at 50°C, introducing methacryloyl substitution groups on the reactive amine and hydroxyl groups of the amino acid residues. The degree of methacryloyl substitution can be adjusted to tune the mechanical properties of the resulting hydrogels. Photocrosslinking of the product GelMA can be conducted using a water-soluble initiator under UV light. The physical properties of GelMA hydrogels, such as porosity, compressive modulus, and water swelling, as well as cell response parameters, are key to determining their suitability for different tissue engineering applications. GelMA hydrogels can be subjected to cryogenic treatments to generate porous scaffolds with controlled pore sizes and porosity. The microfabrication of GelMA hydrogels has been explored using various techniques, including photopatterning, micromolding, self-assembly, and microfluidics, to create complex architectures and control cell-material interactions. These techniques have enabled the fabrication of 3D microgels, cell-laden constructs, and vascularized tissues. Bioprinting has also been used to generate cell-laden constructs with controlled architectures for tissue engineering applications. Hybrid hydrogels based on GelMA have been developed to enhance the mechanical properties of GelMA hydrogels, which are suitable scaffolds for cell growth. These hybrid hydrogels have been used to improve the mechanical strength and electrical conductivity of GelMA hydro