31. It is a nonresorbable polyacrylamide hydrogel made of cross-linked polyacrylamide and water. 32. In 1998, silicone hydrogels became available. 33. He invented polyhydroxyethylmethacrylate, the synthetic material used for soft contact lenses ( hydrogel ). 34. Hydrogels made from PAAc are especially common because of their bioadhesive properties and tremendous absorbency.35. Once bound, a chemical reaction takes place that triggers a reaction from the hydrogel . 36. In addition to just cells, extrusion printers may also use hydrogels infused with cells. 37. Collagen hydrogels would be nontoxic and biocompatible. 38. The hydrogel layer works as a simplified intermediary bond for DNA or other organic materials. 39. Highly specialized hydrogels have been developed for the delivery and release of drugs into specific tissues. 40. This shows that the nanoparticle-loaded hydrogel coating does not significantly hinder the electrical transport.