A network of cross-linked hydrophilic macromolecules used in biomedical applications fabricated by photopolymerization of polyethylene glycol dimethacrylate. Its general formulae is C3H5C(O)(OCH2CH2)nOC(O)C3H5 where n denotes a number of average polyglycol (OCH2CH2) repeats.

The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight [1.00784; 1.00811]. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.