Hydrogel

Hydrogel is a network of polymer chains that are water-insoluble, sometimes found as a colloidal gel in which water is the dispersion medium. Hydrogels are superabsorbent (they can contain over 99% water) natural or synthetic polymers. Hydrogels possess also a degree of flexibility very similar to natural tissue, due to their significant water content.

Common uses for hydrogel are:

• now used as scaffolds in tissue engineering.when used in tissue engineering as scaffolds hydrogels may contain human cell to tissue repair.
• environmentally sensitive hydrogels.These hydrogels have the ability to sense changes of pH, temperature, or the concentration of metabolite and release their load as result of such a change.
• as sustained-release delivery system
• provid absorption,desloughing and debriding capacities of necrotics and fibrotic tissue.

bio_sensors

• HYDROGELS that are responsive to specific molecules ,such as ^{glucose or antigens} can be used as biosensers as well as in DDS.
• In disposable diapers where they "capture" urine, or in sanitary towels
• Contact lenses (silicone hydrogels, polyacrylamides)
• medical electrodes using hydrogels composed of cross linked polymers (polyethylene oxide, polyAMPS and polyvinylpyrrolidone)

Other, less common uses include:

• Breast implants
• Granules for holding soil moisture in arid areas
• Dressings for healing of burn or other hard-to-heal wounds.Wound GEL are excellent for helping to creat or maintain environment.
• reservoirs in topical drug delivery; particularly ionic drugs, delivered by iontophoresis (see ion exchange resin)

Common ingredients are eg. polyvinyl alcohol, sodium polyacrylate, acrylate polymers and copolymers with an abundance of hydrophilic groups.