Others

PEG copolymers are copolymers formed by combining polyethylene glycol (PEG) with other polymers or compounds. PEG is a linear polymer with multiple oxy-vinyl repeating units and has good water solubility, biocompatibility and low toxicity. By copolymerizing PEG with other polymers or compounds, materials with a wide range of properties and functions can be obtained. BOC Sciences offers a wide range of PEG copolymer products in addition to Dendrimer PEG, PEG-PCL, PEG-PGA, PEG-PLA, and other types of copolymers.

Fig. 1. Preparation and characterization of mPEG-PEI-AuNRs and mPEG-PEI/CaNPs (Advanced Functional Materials. 2021, 31(10): 2009314).

Examples of PEG Copolymers

mPEG-PTMC

mPEG-PTMC is a copolymer comprising Methoxy Linear PEG (mPEG) and poly(trimethylene carbonate) (PTMC). Wherein, PTMC is a polyester that can be synthesized by ring-opening polymerization of trimethylene carbonate monomer. And doping mPEG into PTMC can form a copolymer having a balance of hydrophilicity and hydrophobicity. Depending on the desired application, mPEG-PTMC, can be formulated as nanoparticles, hydrogels, and other delivery systems.

PLCL-PEG-PLCL

PLCL-PEG-PLCL is a triblock copolymer consisting of poly(lactic acid-co-caprolactone) (PLCL) and PEG. PLCL is a copolymer made by polymerization of lactic acid and caprolactone monomers, and the degradation rate and mechanical properties of the material can be adjusted by adjusting the ratio of lactic acid to caprolactone. PLCL-PEG-PLCL can be used as a carrier for drug delivery systems, and drug release can be achieved by adjusting the structure and morphology of the copolymer.

mPEG-PVL

PVL is a polyester derived from the cyclic monomer ε-valerolactone. By incorporating PVL into mPEG, it is possible to impart biodegradability to the material. mPEG-PVL can be prepared in a variety of ways, yielding products with varying ratios of mPEG to PVL.

How are PEG Copolymers Modified?

End Modification

End modification is a type of PEG copolymer that can be achieved by introducing different functional groups at the end of the PEG chain. Methods of modification include:

(1) Hydroxylation modification. Reaction at the end of the PEG copolymer with active hydrogen compounds, which can be anhydrides, chlorides, esters, etc.

(2) Amine-based modification. A compound of active halogen or anhydride is introduced at the end of the PEG copolymer, which in turn introduces amine functional groups into it.

(3) Thiolation modification. In addition to the above types of end modifications, compounds with double sulfur bonds can be bonded to the PEG copolymer to introduce thiol functional groups.

Surface Modification

The surface modification of the PEG copolymer may include the following types:

(1) Covalent bonding modification. Covalent bond modification can be carried out on the surface of PEG copolymer, and the modification methods include esterification and amidation, to form a stable PEG surface coating, which in turn provides good biocompatibility and anti-protein adsorption properties.

(2) Physical adsorption modification. This modification can be achieved by immersing the modified material in a solvent in which the PEG copolymer is dissolved, causing the PEG copolymer to adsorb onto the surface of the material.

(3) Self-assembly modification. PEG copolymers can be coated on the surface of the material to form a self-assembled structure by self-assembly of PEG copolymers containing hydrophobic tails.

Advantages of PEG Copolymers

• Resistance to protein adsorption. PEG copolymer surfaces are highly resistant to protein adsorption, reducing non-specific protein adsorption and cell adhesion.
• Modulation of material properties. By changing the molecular weight, structure, density and other parameters of PEG copolymers, it is possible to regulate the mechanical properties, surface properties and dispersibility of the materials.
• Multifunctionalization. PEG copolymers can be multifunctionalized by covalently or non-covalently combining with other functional molecules or active substances.

Reference

1. Xu, C. et al. Effective Eradication of Tumors by Enhancing Photoacoustic‐Imaging‐Guided Combined Photothermal Therapy and Ultrasonic Therapy. Advanced Functional Materials. 2021, 31(10): 2009314.