m-dPEG®₂-NHS ester




m-dPEG®2-NHS ester, product number 10327, is a very short, methyl-terminated, discrete length polyethylene glycol (dPEG®) spacer, designed for modification of surfaces containing accessible free amines. The carboxyl terminus of the molecule is activated with N-hydroxysuccinimide (NHS). NHS reacts optimally with free amines at pH 7.2 – 7.5. The active ester’s rate of hydrolysis to the carboxylic acid accelerates with increasing pH. Please note that modification of surface amines on biomolecules (e.g., proteins and peptides) with this uncharged, methyl-capped dPEG® spacer may alter the overall charge of the resulting conjugates.

Numerous applications employ this product. The applications in which this product has been successfully employed include:

  • surface modification of silica-shelled quantum dots;
  • coating of carbon nanotubes and other hydrophobic surfaces;
  • N-terminal peptide modification; and
  • various imaging applications.

One potential applications for this product include charge modification of a biomolecule by modifying positively charged free amines with the uncharged m-dPEG®2-NHS ester. Another potential application is to use m-dPEG®2-NHS ester in a mixed surface modification (for example, an amine-coated glass or silica surface) where the shorter dPEG® product passivates the surface while longer dPEG® products contain reactive groups for additional functionalization of the surface. As an example, please see Figure 3 in Three Click Chemistry Ideas for PEGylation Reagents.

m-dPEG®2-NHS ester, product number 10327, is just one member of an extensive line of methyl-terminated dPEG® products. This line includes dPEG® spacers containing 4 to 25 ethylene glycol units. These products are functionalized with NHS or with 2,3,5,6-tetrafluorophenol (TFP). TFP has proven to be superior to NHS for amine-reactive products. For more information on the superior performance of TFP esters, please see our page TFP Esters Have More Hydrolytic Stability and Greater Reactivity than NHS Esters.

Quanta BioDesign, Ltd., makes and sells single molecular weight PEG linkers and spacers with discrete chain lengths under the trade name dPEG®. Our products are distinctly different from traditional PEG products in that they are not disperse polymers. However, they confer all of the benefits of traditional PEG products. To learn more about dPEG® products, please read our page What is dPEG®? Please also visit our Frequently Asked Questions page to get answers to the questions we answer most often.

Additional information

Weight .5 oz
Dimensions .75 × .75 × 2 in

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