Introduction

The CH2COOH-PEG3-CH2COOH is used for modifying proteins or surfaces such as beads, nanoparticles and self-assembled monolayers. Modification of proteins adds polyethylene glycol (PEG)_n spacers, which impart increased water solubility, reduced immunogenicity of the labeled molecule and enhanced in vivo stability in solution. Functionalization of solid surfaces, such as quantum dots, self-assembled monolayers and nanoparticles, with polyethylene glycol spacers significantly reduces nonspecific protein binding. (PEG)n amine reagents used with (PEG)n amine reagents in surface modification can form a hydrophilic “lawn” of methyl ether-terminated PEGs with periodic exposed carboxy-terminated PEGs. The exposed carboxy groups can be coupled to affinity ligands using the carbodiimide coupling reaction with EDC and sulfo-NHS.

Typical PEGylation reagents contain heterogeneous mixtures of different PEG chain lengths; however, our PEGylation reagents are homogenous compounds of defined molecular weight and spacer length, providing precision in optimizing modification applications.