It is a network of hydrophilic polymer chains, sometimes occurring as a colloidal gel in which water is the dispersion medium. The polymers may be of natural or synthetic origin.

The following are the uses of hydrogels:

1. They are used as scaffolds in tissue engineering. This form may contain human cells to repair tissues.
2. Hydrogel-coated wells have been used for cell culture.
3. Environmentally sensitive hydrogels (smart gels or intelligent gels) have the ability to sense changes in pH, temperature or concentration of metabolite and release their load as result of such a change.
4. These are used in sustained-release drug delivery systems.
5. They provide absorption, desloughing and debriding of necrotic and fibrotic tissues.
6. They can be used as biosensors as well as in drug delivery systems (DDS).
7. They are used in disposable diapers where they absorb urine and in sanitary napkins.
8. Contact lenses are designed using silicone hydrogels and polyacrylamides.
9. They are used in EEG and ECG medical electrodes.
10. They are used in water gel explosives.
11. They are used in rectal drug delivery and diagnosis.
12. They are used in breast implants.
13. They are used in glues.
14. They are used in the preparation of granules for holding soil moisture in arid areas.
15. Wound gels are used for helping to create or maintain a moist environment.
16. They are used for reservoirs in topical drug delivery