PEG-Plys Polylysine

What is PEG-Plys?

PEG-Plys (Polylysine) obtains the properties and advantages of both by combining PEG and polylysine. The introduction of a PEG chain improves the solubility, stability, and biocompatibility of polylysine and extends its circulation time in vivo. PEG-Plys can be used to improve the aqueous solubility of drugs, modulate the targeting of drugs, increase biological activity, etc. They have potential applications in drug delivery, tissue engineering, diagnostic technology and other fields.

Fig. 1. PEG-b-PLys(Ube)s as a type of modified ubenimex (Oncogene. 2019, 38(2): 244-260).

Examples of PEG-Plys

MAL-PEG-Plys

MAL-PEG-Plys are biodegradable polymeric organic compounds conjugated with PEG and polylysine. It is a linear amphiphilic block copolymer with a hydrophobic Plys portion and a hydrophilic PEG portion. The Plys portion has free amine groups in the side chain, which provides good membrane permeability. Various reactive groups in the Plys-PEG derivatives can be crosslinked with different molecules. The PEG portion contains maleimide groups, which can react selectively with thiols by Michael addition to form stable C-S bonds at pH 6.5-7.5. Therefore, MAL-PEG-Plys can be used to modify proteins, peptides or other surfaces containing sulfhydryl groups.

COOH-PEG-Plys

COOH-PEG-Plys can be used to introduce carboxyl groups into cross-linked PEG hydrogels. It can be used in cell culture, drug research, drug delivery and release, nanotechnology and new materials. It can also be attached to different molecules or materials to extend the richness of different molecular combinations.

NHS-PEG-Plys

Various reactive groups in NHS-PEG-Plys can be crosslinked to different molecules. NHS is a white crystalline substance that can be used as a pharmaceutical intermediate for the production of semi-synthetic kanamycin or as a linker for the solid-phase synthesis of peptides. NHS-PEG-Plys can be easily incorporated into liposomes and other nanoparticles through the NHS-amine reaction.

How to Prepare PEG-Plys?

1. Pre-treatment of the Product. Polylysine can be prepared by chemical synthesis or biosynthesis. Chemical synthesis can be achieved by linking lysine amino acid units together to form a polypeptide chain. Biosynthesis method can use genetic engineering technology to obtain polylysine by protein synthesis through lysine gene expression.

2. Conjugation of PEG-Plys. Conjugation of PEG-Plys requires activation of PEG, a process that involves reacting PEG with an activator to introduce a reactive ester or amide group at the end of the PEG chain. PEG-Plys copolymers were produced by reacting activated PEG with amino acid residues in polylysine. Subsequently, the synthesized PEG-Plys copolymers were crystallized, purified and isolated.

Safety of PEG-Plys Copolymers

Toxicity and Metabolites

PEG is a relatively safe polymer with low toxicity. However, the length and density of the PEG chains may affect its metabolism and clearance. Long-chain PEG may be more difficult to clear by the liver and kidneys, which may lead to accumulation or other undesirable effects. Therefore, careful toxicity assessment is required for the use of long chain PEG-Plys copolymers.

Reduction of Immunogenicity

The introduction of PEG chains reduces the immunogenicity of polylysine and decreases interactions with proteins and cells in organisms. However, individual biocompatibility of derivatives may vary, so appropriate in vitro and in vivo evaluations should be performed prior to use.

BOC Sciences specializes in the research, development, production and marketing of polyethylene glycols and their active derivatives. In addition to PEG-Plys copolymers, we can also provide you with PEG customized synthesis services to synthesize copolymers of different compositions as well as different molecular weights.

Reference

1. Toshiyama, R. et al. Poly (ethylene glycol)–poly (lysine) block copolymer–ubenimex conjugate targets aminopeptidase N and exerts an antitumor effect in hepatocellular carcinoma stem cells. Oncogene. 2019, 38(2): 244-260.