This review article focuses on the design, fabrication, and characterization of polyethylene glycol (PEG) hydrogels for controlled release of biomolecules in regenerative medicine. PEG hydrogels are widely used due to their biocompatibility and ability to encapsulate cells and biomolecules. The article discusses different polymerization mechanisms, such as chain-growth, step-growth, and mixed-mode polymerization, and their impact on gel properties. Key aspects include the availability and stability of biomolecules, loading mechanisms, and spatial and temporal control of delivery. The review also explores emerging applications, such as spatiotemporal-controlled delivery, hybrid hydrogels, and PEG hydrogels for controlled stem cell differentiation. These advancements aim to enhance tissue regeneration by providing precise control over the delivery of therapeutic factors and the microenvironment for cell function.This review article focuses on the design, fabrication, and characterization of polyethylene glycol (PEG) hydrogels for controlled release of biomolecules in regenerative medicine. PEG hydrogels are widely used due to their biocompatibility and ability to encapsulate cells and biomolecules. The article discusses different polymerization mechanisms, such as chain-growth, step-growth, and mixed-mode polymerization, and their impact on gel properties. Key aspects include the availability and stability of biomolecules, loading mechanisms, and spatial and temporal control of delivery. The review also explores emerging applications, such as spatiotemporal-controlled delivery, hybrid hydrogels, and PEG hydrogels for controlled stem cell differentiation. These advancements aim to enhance tissue regeneration by providing precise control over the delivery of therapeutic factors and the microenvironment for cell function.