Hydrogel Variability in Drug Delivery: Balancing Mechanical Strength and Stimuli-Responsiveness

Hydrogels have garnered significant attention as eco-friendly, renewable soft materials in the context of achieving Sustainable Development Goals (SDGs). These hydrogels can be broadly categorized into two types based on the formation of the crosslinked gel network that holds water molecules: those held together by covalent bonds and those formed through non-covalent processes. Covalently bonded hydrogels exhibit robust mechanical properties, including tensile strength, viscosity, and elasticity, while non-covalent bond-based hydrogels offer the advantage of responsiveness to external stimuli. Specifically, hydrogels assembled through non-covalent molecular aggregates can be precisely tailored to achieve ordered structures and diverse functionalities, making them promising candidates for advanced intelligent drug delivery systems (DDS).<br/>When hydrogels are employed in DDS applications, the preservation of their shape until they reach the target site, serving as carriers for model drugs, necessitates substantial mechanical strength.<br/>Within our research group, we have successfully developed a range of hydrogels using both covalent and non-covalent bonds as binding mechanisms. These hydrogels have been fabricated from materials such as natural polysaccharides, proteins, and supramolecular compounds. We have rigorously assessed the mechanical properties of these gels and conducted investigations into the correlation between their mechanical attributes and drug encapsulation and release behaviors.