Polyethylene glycol (PEG), also known as polyethylene oxide (PEO) in certain molecular-weight ranges and applications, is a polymer composed of repeating ethylene oxide units. PEG derivatives are produced by modifying PEG with different terminal functional groups or polymer architectures to meet specific research and development needs.
PEG derivatives can be classified by molecular weight distribution, polymer architecture, and functional groups. These classifications describe different structural features and are not mutually exclusive. For example, a heterobifunctional PEG can be either monodisperse or polydisperse.
Classification by Molecular Weight Distribution
PEG derivatives are commonly classified as monodisperse or polydisperse PEGs according to their molecular weight distribution.
Monodisperse PEG: Monodisperse, or discrete, PEG consists of molecules with a defined number of ethylene oxide repeat units and a specific molecular weight. Biopharma PEG offers monodisperse PEG derivatives with linear chains Varing from 2 to 72 –CH₂CH₂O– repeat units and with various functional groups for applications requiring precise molecular structures, including bioconjugation and linker synthesis.
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Polydisperse PEG: Polydisperse PEG consists of polymer chains with a distribution of molecular weights and chain lengths. It is commonly characterized by its average molecular weight and dispersity. Biopharma PEG also provides polydisperse PEGs with various functional groups and molecular weight.
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Classification by Polymer Structure
1. Monofunctional PEG Derivatives(mPEG-X)
Monofunctional PEG Derivatives refer to monofunctional linear PEG derivative with an methoxyl (mPEG)at one end and one functional group at the other end of the PEG polymer. Monofunctional PEG is useful when a single attachment site is required.
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2. Homobifunctional PEG Derivatives(X-PEG-X)
Homobifunctional PEG Derivatives has the same functional groups at both end of the PEG linear chain. These derivatives can be used as crosslinkers or spacers when both ends need to participate in the same type of reaction.
3. Heterobifunctional PEG Derivatives(X-PEG-Y)
Heterobifunctional PEG Derivatives contain two different functional groups at each terminal of the PEG chain. The two functional groups allow sequential or orthogonal coupling to different molecules. These PEG derivatives are widely used in bioconjugation, linker synthesis, and surface modification, where controlled attachment at two distinct sites is required.
4. Branched PEGs (U-shape PEGs and Y-shape PEGs)
Branched PEGs commonly adopt Y-shaped or U-shaped architectures and contain multiple reactive sites within a single molecule.
5. Multi-arm PEG
Multi-arm PEG derivatives consist of multiple PEG chains extending from a central core. Common architectures include 3-arm, 4-arm, 6-arm, and 8-arm PEG.
Multi-arm PEG derivatives prepared by ethoxylation of different cores such as pentaerythritol, hexaglycerol, or tripentaerythritol, and incorporation of reactive moieties, are cross-linked easily into threedimensional hydrogel materials.
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Classification by Functional Group Chemistry
PEG derivatives can be classified by their terminal functional groups, which determine their reactivity and applications, such as Amine (-NH₂) and carboxyl (-COOH) PEGs for coupling reactions and surface functionalization, NHS ester PEG, maleimide PEG, Azide and alkyne/DBCO PEGs for click chemistry, Thiol (SH) PEGs, aldehyde PEGs and PEG lipids (DSPR or DMG PEGs), etc.
The appropriate PEG functional group depends on the target molecule, desired linkage, and reaction conditions.
PEG Derivatives for Research and Development
Biopharma PEG provides PEG derivatives with a range of molecular weights, architectures, and functional groups for bioconjugation, PEGylation, linker synthesis, crosslinking, and biomaterials research. Researchers can explore the PEG product catalog or discuss custom PEG synthesis for specific structural and functional requirements.
Custom synthesis PEGs provide a wide variety of PEG products for different reactions, used to modify active pharmaceutical ingredients, peptides, proteins, antibody components, oligonucleotides, and so forth.
Rlated Articles
How to Choose PEG Linker: Molecular Weight, Structure and Functionality
What Is Polyethylene Glycol (PEG)? Properties and Applications
What Are PEG Linkers & Their Applications?
Ultimate Insight into PEG Linkers and Its Application
The Difference Between Monodisperse and Polydisperse Polymers
