Polysarcosine (PSR) – originating from the natural, non-toxic amino acid sarcosine (N-Methylglycine) – is the simplest polypeptoid and a newly rediscovered biocompatible and degradable polymer. Polysarcosine has been employed in a number of drug delivery systems, including dendrimers, polymer micelles, polyplexes, protein conjugates and micro- and nanoparticles, polymersomes and nanotubes. However, widespread use of PSR has been hampered by lack of commercially-available functional PSR in good quality.

The use of PSR with functional head- and tail-groups for bioconjugation is comparable to the well-known PEGylation technology.