Amino-dPEG®₄-OH

Amino-dPEG®4-OH, product number QBD-10249, is a monodisperse PEGylation reagent designed for chemical modification of biomolecules and surfaces. The primary amine on one end of the molecule reacts with carboxylates to form amide bonds and with aldehydes and ketones to form labile Schiff bases. The hydrophilic, non-immunogenic, discrete polyethylene glycol (dPEG®) spacer improves water solubility and increases the hydrodynamic volume of conjugates. The terminal hydroxy group can be modified to add different functional groups.

When used to modify biomolecules or passivate surfaces, amino-dPEG®4-OH creates an extremely hydrophilic coating on the modified surface or molecule. The primary amine on one end of the dPEG® linker reacts with carboxylates, aldehydes, and ketones. Conjugations with this molecule most commonly use the amine-carboxylate reaction because it forms stable amide bonds. A carbodiimide such as EDC directly connects the amino group to a carboxylate. Alternatively, activation of carboxylate as the NHS or TFP ester followed by reaction under slightly basic conditions also permits conjugation of the carboxylate and amino moieties.

The amino group also reacts with aldehydes and ketones to form Schiff bases. Schiff bases are reducible to secondary amines for improved stability.

The published uses of Amino-dPEG®4-OH include the following:
Surface coating of iron oxide nanoparticles;
Surface coating of quantum dots;
Development of a confocal imaging system to measure passive transport across membranes; and,
Development of a label-free detector of pyrophosphate.