When used as a modification on oligonucleotides, the polymer polyethylene glycol (PEG) can fulfill a wide range of functions depending on its length.

Primarily, PEG increases the molecular weight of an oligo and its steric size. PEG is hydrophilic and can transfer this property to the attached molecule, improving solubility in water. This can be of interest, for example, as a countermeasure to highly hydrophobic oligo modifications.

Furthermore, the increased hydrophilicity and steric size of the PEG chain protect DNA and RNA oligos from hydrolysis by nucleases, thereby increasing the molecule’s stability. Longer PEG chains offer greater protection against nucleases but lower the melting temperature of the attached oligo more significantly than shorter chains.

Due to these properties, PEG-modified oligos and other biomolecules are used in various therapeutics, where PEG, for example, increases the residence time in the body or reduces the adsorption of the biomolecules to proteins.

Biomers.net offers PEG-modifications of varying lengths(modification catalog). Next to large, heavy chains (5k-40k) we offer short flexible linkers (Spcaer9, Spacer12, Spacer18).

The long-chain PEG modifications offered are normally distributed mixtures with molecular weights centered around the value specified in the name.

Literature:

1. Impacts of PEGylation on the gene and oligonucleotide delivery system. Ikeda Y, Nagasaki Y; J. Appl. Polym. Sci. (2014), 131, 40293. doi: 10.1002/app.40293.

2. Stabilization and Photochemical Regulation of Antisense Agents through PEGylation- Govan JM, Mclver AL, Deiters A; Bioconjugate Che. (2011) 22 (10): 2136-2142. doi: 10.1021/bc200411n.

3. PEGylated therapeutics in the clinic. Gao Y, Joshi M, Zhao Z, Mitragotri S; Bioeng. Transl. Med. 9(1):e10600. doi: 10.1002/btm2.10600.