Hydrogels are three-dimensional networks of hydrophilic polymers that can retain large amounts of water while maintaining their structure. They are widely used in various applications, including biomedical fields for drug delivery and tissue engineering due to their biocompatibility and ability to mimic natural tissue properties. These materials can be synthesized from natural or synthetic sources and can respond to environmental stimuli, making them versatile for use in wound dressings, contact lenses, and agriculture. Their unique properties allow them to swell and shrink, providing innovative solutions in many industries.