Mono dispersed polyethylene glycol PEG linkers have been widely used in ADC bioconjugation research. It provides the research community a powerful tool to improve the physio-chemical property of the bioconjugation complex. Often times, better aqueous solubility and reduced immunogenicity can be achieved.

At AxisPharm we retain a large collection of high purity PEG reagent, PEG linkers and PEGylation products in stock to empower your PEG related research and development. Our high pure mono dispersed PEG reagents allows researchers to precisely control the spacer length in their conjugation applications. Our broad range of functional groups such as maleimido, azido, NHS ester, amino, aminoxy etc offers powerful tools for site specific conjugations.

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Acid PEG

Acid PEG is a versatile tool in ADC. Carboxylic acid functionalized peg has an acid group on one end of the peg chain and other functional group on the other.

Alkyne PEG

Alkyne PEG has a terminal triple bond on one end and functional groups on the other end. The alkyne triple bond readily react with azide moiety and form stable triazole under mild condition. The resulting triazole is considered a bio isostere of amide, which has minimal effect to the conjugated biomolecules. The other functional group can then be utilized for further conjugation applications.

Amine PEG

Amine PEG linkers contain an amino group on one end of the peg spacer. They can easily couple with acids, acyl chloride, NHS esters, or PFP esters. As a result, the crosslinkers have been widely used for labeling, bioconjugation, chemical modification, and surface applications.

Amino Peg Acid

Amino PEG acid, also named as amine PEG acid, is a class of crosslinkers that has an amino group on one end of the PEG spacer and an acid on the other.

Aminooxy PEG Linkers

The aminooxy PEG linkers react with aldehydes and ketones to form stable oxime linkages. The linkages formed can be cleaved under acidic conditions.
AxisPharm’s aminooxy-PEG linkers are available with various functional group combinations, such as amine, ester and azide, biotin and with copper free click chemistry tools such as TCO, DBCO, BCN etc.

Biotin Linkers

Biotin PEG linkers are useful tools in nonradioactive purification, detection, immobilization, labeling, and targeting. The interaction affinity between biotin (vitamin H) and avidin is one the strongest. It allows biotin-containing molecules rapidly and discretely bound with avidin conjugates. The formed complex becomes stable under extreme pH, temperature, organic solvents and other denaturing agents.

Boc amine PEG

Boc amine PEG has a Boc protected amine group on one end of PEG crosslinker and other functional group on the other.

The Boc protection group can be easily removed under acidic condition to release the free amine, which can be used to conjugate with amine reactive biomolecules.

Branched Linkers Multi-Arm PEG Linkers

Branched Linkers have drawn much of attention in ADC research and development. It provides researchers an opportunity to get higher concentration of ADC payloads to the target cell per unit of binding antibody by improving DAR.

Bromo PEG

Bromo PEG is a PEG derivative containing a terminal bromide group on one end and another functional group on the other end.

Bromo (Br) is a very good leaving group for nucleophilic substitution reactions. Various bromo PEG linkers have been used for bio-conjugations through formation of sulfide bond with thiol moiety on bio-molecules.

Fmoc PEG Linkers

Fmoc PEG linkers have Fmoc protected amine on one end and other functional groups on the other end. The classic Fmoc deprotection makes the linker a versatile tool for bioconjugation and peptide pegylations. The deprotected free amino group can be further functionalized or used directly for another bioconjugation.

Homobifunctional PEG

Homobifunctional PEGs are synthetic polyethylene glycol derivatives containing two of the same type of functional groups, such as amines, azides, maleimides, NHS esters, and thiols. Homobifunctional PEG derivatives are widely used for surfaces, nanomaterials, proteins, peptides, and other biomolecules research.


PEG NHS ester linkers have been widely usded for crosslinking or labeling peptides and proteins. They readily react with primary amine groups at the N-terminus of polypeptide chains and lysine amino groups. These primary amines exist predominantly on the outside surfaces of protein and are readily accessible to NHS ester for bioconjugations. In addition, these primary amines are nucleophilic enough to react with PEG NHS esters for protein crosslinking and labeling.

Thiol PEG

Thiol PEG linkers have reactive thiol moiety on one side of the linear peg chain. The thiol functional group readily react with biomolecules with maleimide, halogen acetate, thiol, cysteine, and OPSS. It has also been widely used surface modification of gold, and silver, etc. Surface-grafted poly(ethylene glycol) (PEG) molecules are known to prevent protein adsorption to the surface.