O-(3-Carboxypropyl)-O′-[2-(3-mercaptopropionylamino)ethyl]-polyethylene glycol

Circulatory half-life is a key success factor for new drugs. In this respect, PEGylation or PEG-ing—the modification of potential candidates ranging from non-peptidic small molecules to peptides and proteins, antibody fragments, aptamers, and saccharides or oligonucleotides with polyethylene glycol chains—offers numerous advantages.

Progress in biotechnology fields such as tissue engineering and drug delivery is accompanied by an increasing demand for diverse functional biomaterials. One class of biomaterials that has been the subject of intense research interest is hydrogels, because they closely mimic the natural environment of cells, both chemically and physically and therefore can be used as support to grow cells. This article specifically discusses poly(ethylene glycol) (PEG) hydrogels, which are good for biological applications because they do not generally elicit an immune response. PEGs offer a readily available, easy to modify polymer for widespread use in hydrogel fabrication, including 2D and 3D scaffold for tissue culture. The degradable linkages also enable a variety of applications for release of therapeutic agents.