PEG Derivatives by Functional Groups

At BOC Sciences, we specialize in the synthesis and production of functional PEG derivatives. Our team of experts has many years of experience in this field and can provide customized PEG derivatives to meet specific needs. We offer a wide range of PEG derivatives with different functional groups, including carboxylic acids PEG, aldehydes PEG, cholesterol PEG, biotin PEG, and more. Our PEG derivatives are of the highest quality and are thoroughly tested to ensure their purity and efficacy. We also offer competitive pricing and superior customer service, making us the preferred choice for PEG derivatives by functional group.

In addition, BOC Sciences has extensive experience in manufacturing PEG-based products, including PEGylated reagents, PEGylated proteins, and PEGylated liposomes. Our PEG cGMP manufacturing services are designed to meet the strict regulatory requirements of the pharmaceutical industry, ensuring that all products are manufactured in compliance with current Good Manufacturing Practices (cGMP). This includes the use of state-of-the-art equipment, strict quality control processes and highly trained personnel to ensure the highest level of product quality and consistency. Our cGMP manufacturing services also include comprehensive analytical testing and documentation to ensure the quality and purity of all products. This includes a range of analytical techniques such as HPLC, NMR and mass spectrometry to verify the identity, purity and potency of each product.

What's Polyethylene Glycol?

PEG is a hydrophilic polymer consisting of repeating glycol units. The chemical properties of PEG derivatives can be altered through the introduction of various functional groups to enhance their physicochemical properties. PEG derivatives can be modified with a variety of functional groups including carboxylic acids, amines, sulfhydryl groups, and others. PEG derivatives modified by functional groups hold great promise in a variety of fields, allowing precise control of their properties and expanding their range of applications. The chemical and structural characteristics of these derivatives contribute to their functionality in drug delivery systems, biomaterials, and synthetic polymers. PEG derivatives offer many advantages, including biocompatibility and customizability, and play a vital role in advancing biomedical research and applications.

What is PEG Used For?

Polyethylene glycol is nontoxic, generally nonimmunogenic, and is approved by the FDA for use as an excipient or carrier in pharmaceutical formulations, foods, and cosmetics. Most PEGs with molecular weights <1000 are rapidly cleared from the body, with clearance rates inversely proportional to the polymer molecular weight. In addition, a variety of functional groups can be connected to the ends of PEG polymers to give the polymer more functions. Therefore, PEG has a wide range of applications in biomedical research, including bioconjugation, drug delivery, surface functionalization, tissue engineering, and many other applications.

Ligand functionalized polyethylene glycol particlesFig. 1. Ligand-functionalized polyethylene glycol particles for tumor targeting (Biomacromolecules. 2019, 20(9): 3592-3600).

PEG conjugation is the covalent bioconjugation of drug targets such as peptides, proteins or oligonucleotides to PEG to optimize pharmacokinetic properties. In drug delivery, PEG can be used as a linker for antibody-drug conjugates (ADCs) or as a surface coating on nanoparticles to improve systemic drug delivery. PEG hydrogel is a water-swollen three-dimensional polymer network that resists protein adhesion and biodegradation. PEG hydrogels are formed by reactive cross-linking of PEG end groups and are commonly used in tissue engineering and drug delivery.

What is the Functional Group of PEG?

PEG is ethylene oxide with ether functional groups. Its general structure is (-O-CH2-CH2-)n, where n represents the number of repeating units in the polymer chain. Each ethylene glycol unit in the PEG chain is connected to the next ethylene glycol unit by an ether linkage, which is a strong and stable bond. This ether linkage gives PEG its unique properties, making it a compound with a wide range of applications. In addition, by changing the length of the polymer chain or introducing different functional groups, the properties of PEG can be tailored to meet the requirements of different industries. For example, PEG can be modified with functional groups to increase its stability, enhance its drug release properties, or improve its compatibility with other ingredients.

Monofunctional PEG

Monofunctional PEG is a PEG derivative containing a single functional group. PEG polymers terminated with methyl groups (methoxy linear PEG (mPEG)) are classified as monofunctional-PEG. It is a PEG derivative containing a single chemically reactive end group, making it ideal for PEGylation, surface modification, and nanoparticle coatings. One of the main advantages of monofunctional PEG is its ability to easily attach to a variety of molecules and surfaces. This is due to the presence of reactive end groups, which can form covalent bonds with other molecules through various chemical reactions. For example, monofunctional PEGs capped with maleimide groups can react with thiol groups on proteins to form stable thioether bonds, allowing PEG to be conjugated to proteins to improve stability and solubility.

BOC Sciences offers a range of monofunctional PEG derivatives in a range of molecular weights, such as amines, maleimides, azides, NHS esters, thiols, and more. The different types of PEG products offered by BOC Sciences allow easy incorporation of PEG into proteins, peptides, surfaces and other materials. For example, monofunctional PEGs with NHS ester groups can be used to modify proteins by reacting with primary amines on the protein surface, while monofunctional PEGs with azide groups can be used in click chemistry reactions to attach PEG to surfaces or nanoparticles.

Bifunctional PEG

Bifunctional PEG is a multifunctional compound containing two active terminal PEGs, including homobifunctional PEG and heterobifunctional PEG. Homobifunctional PEG consists of two PEG chains with identical functional groups at the ends, whereas heterobifunctional PEG contains two different functional groups. One of the major advantages of bifunctional PEGs is their ability to attach and cross-link hydrogels. By using bifunctional PEG as a cross-linker, researchers can modify the mechanical properties, swelling behavior, and biocompatibility of hydrogels to enable a wide range of applications, including drug delivery, tissue engineering, and regenerative medicine. Bifunctional PEGs are also important tools for protein and peptide conjugation. Bifunctional PEGs provide a nontoxic and biocompatible platform for attaching proteins and peptides to surfaces or other biomolecules, enabling controlled and site-specific conjugation. In addition, bifunctional PEG can be used as a linker in drug delivery systems, which can improve the pharmacokinetics, stability, and targeting capabilities of therapeutic agents.

BOC Sciences PEG polymers offer a range of bifunctional PEGs in a range of molecular weights and various functionalities, such as amines, azides, maleimides, NHS esters and thiols. Bifunctional PEG derivatives can be used in many applications, including surface functionalization and nanomaterials, and as cross-linkers for proteins, peptides, and other biomolecules.

Why is PEG Preferred?

The advantages of utilizing polyethylene glycol derivatives through functional group modification are manifold.

  • First, the hydrophilic nature of polyethylene glycol ensures biocompatibility and reduces the chance of immunogenic reactions.
  • In addition, the tunability of PEG derivatives permits precise control of drug release kinetics, improving therapeutic efficacy.
  • The biodegradability of polyethylene glycol derivatives further enhances their utility as they can be enzymatically or chemically degraded, preventing long-term accumulation in the body.
  • In addition, the modularity of the functional groups makes PEG derivatives highly customizable to meet the specific needs of different pharmaceutical and biomedical applications.

BOC Sciences is at the forefront of polyethylene glycol derivative development, offering high-quality products and unrivaled expertise to meet the changing needs of researchers and industries worldwide. If you are interested in our products, please do not hesitate to contact us promptly.


  1. Cui, J. et al. Ligand-functionalized poly(ethylene glycol) particles for tumor targeting and intracellular uptake. Biomacromolecules. 2019, 20(9): 3592-3600.

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BOC Sciences supplies a unique variety of PEG derivatives and functional PEG polymers. Our products offer the most diverse collection of reactivity, ready-to-use functionality, and molecular weight options that you will not find anywhere else.

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