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m-dPEG®₁₂-NHS ester (QBD-10262)



m-dPEG®12-NHS ester, product number QBD-10262, is a medium-length (38 atoms, 44.7 Å), methyl-terminated, discrete-chain-length polyethylene glycol (dPEG®) spacer functionalized with an N-hydroxysuccinimidyl (NHS) ester for reaction with amines.

NHS esters react optimally with free amines at pH 7.0 – 7.5. In aqueous media, the hydrolytic rate of the ester to the carboxylic acid increases with increasing pH. Reacting 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.

Many applications employ this m-dPEG®12-NHS ester. Published papers using this product include uses in:
vaccine development;
cell surface engineering;
multimodal imaging;
stable antimicrobial, cytotoxic dendrimers;
nanoparticles for siRNA delivery;
coating of nanoparticles, quantum dots, and carbon nanotubes;
PK and immunogenicity improvements for organophosphorus hydrolase;
PK and immunogenicity improvements for poly-L-lysine dendrimers used as drug delivery vehicles to tumors; and,
preventing enzyme aggregation.
m-dPEG®12-NHS ester, product number QBD-10262, is just one member of a comprehensive line of methyl-terminated dPEG® products, including dPEG® spacers containing 2 to 49 ethylene glycol units.


Unit Size100 mg, 1000 mg
Molecular Weight685.75; single compound
Chemical formulaC₃₀H₅₅NO₁₆
Purity> 98%
SpacersdPEG® Spacer is 38 atoms and 44.7 Å
Typical solubility properties (for additional information contact Customer Support)Methylene chloride, Acetonitrile, DMAC or DMSO.
Storage and handling-20°C; Always let come to room temperature before opening; be careful to limit exposure to moisture and restore under an inert atmosphere; stock solutions can be prepared with dry solvent and kept for several days (freeze when not in use). dPEG® pegylation compounds are generally hygroscopic and should be treated as such. This will be less noticeable with liquids, but the solids will become tacky and difficult to manipulate, if care is not taken to minimize air exposure.


Greg T. Hermanson, Bioconjugate Techniques, 3rd Edition, Elsevier, Waltham, MA 02451, 2013, ISBN 978-0-12-382239-0; See Chapter 18, Discrete PEG Reagents, pp. 787-821, for a full overview of the dPEG® products.

The impact of molecular Weight and PEG Chain Length on the Systemic Pharmacokinetics of PEGylated Poly L-Lysine Dendrimers. Lisa M. Kaminskas, Ben J. Boyd, Peter Karellas, Guy Y. Krippner, Romina Lessene, Brian Kelly, and Christopher J. H. Porter. Molecular Pharmaceutics. 2008, 5 (3), pp 449–463. April 5, 2008. DOI: 10.1021/mp7001208.

Pharmacokinetics and Tumor Disposition of PEGylated Methotrexate Conjugated Poly-L-lysine Dendrimers. Lisa M. Kaminskas, Brian D. Kelly, Victoria M. McLeod, Ben J. Boyd, Guy Y. Krippner, Elizabeth D. Williams, and Christopher J. H. Porter, Molecular Pharmaceutics, Vol. 6, No. 4, 2009, 6 (4), pp 1190-1204, May 19, 2009. DOI: 10.1021/mp900049a.

Hairpin Structure of a Biarsenical- Tetracysteine Motif Determined by NMR Spectroscopy. Fatemeh Madani, Jesper Lind, Peter Damberg, Stephen R. Adams, Roger Y. Tsien, and Astrid O. Graslund. Journal of the American Chemical Society. 2009, 131 (13), pp 4613–4615. March 12, 2009. DOI: 10.1021/ja809315x.

Improved pharmacokinetics and immunogenicity profile of organophosphorus hydrolase by chemical modification with polyethylene glycol. Boris N. Novikov, Janet K. Grimsley, Rory J. Kern, James R. Wild, Melinda E. Wales. Journal of Controlled Release. 2010, 146 (3) pp 318-325. September 15, 2010. DOI: 10.1016/j.jconrel.2010.06.003.

Antibacterial activity and cytotoxicity of PEGylated poly(amidoamine) dendrimers. Analette I. Lopez, Rose Y. Reins, Alison M. McDermott, Barbara W. Trautner and Chengzhi Cai. Molecular BioSystems. 2009, 10 (5) pp 1148–1156. May 26, 2009. DOI: 10.1039/b904746h.

Stability, Antimicrobial Activity, and Cytotoxicity of Poly(amidoamine) Dendrimers on Titanium Substrates. Lin Wang, Uriel J. Erasquin, Meirong Zhao, Li Ren, Martin Yi Zhang, Gary J. Cheng, Yingjun Wang, and Chengzhi Cai. ACS Applied Materials & Interfaces. 2011, 3 (8), pp 2885-2894. July 20, 2011. DOI: 10.1021/am2004398.

Prevention of benzyl alcohol-induced aggregation of chymotrypsinogen by PEGylation. José A. Rodríguez-Martínez, Izarys Rivera-Rivera and Kai Griebenow. Journal of Pharmacy and Pharmacology. 2011, 63 (6), pp 800–805. January 6, 2011. DOI: 10.1111/j.2042-7158.2011.01288.

Development and Application of a Multimodal Contrast Agent for SPECT/CT Hybrid Imaging. Jason M. Criscione, Lawrence W. Dobrucki, Zhen W. Zhuang, Xenophon Papademetris, Michael Simons, Albert J. Sinusas and Tarek M. Fahmy. Bioconjugate Chemistry. 2011, 22 (9), pp 1784–1792. August 18, 2011. DOI: 10.1021/bc200162r.

Antibacterial Activities of Poly (amidoamine) Dendrimers Terminated with Amino and Poly(ethylene glycol) Groups. Michelle K. Calabretta, Amit Kumar, Alison M. McDermott, and Chengzhi Cai. Biomacromolecules. 2007, 8 (6) pp 1807-1811. May 19, 2007. DOI: 10.1021/bm0701088.

Enhancement of the CD8+ T cell response to a subdominant epitope of respiratory syncytial virus by deletion of an immunodominant epitope. Hoyin Mok, Sujin Lee, David W. Wright, and James E. Crowe Jr. Vaccine. 2008, 26 (37) pp 4775-4782. September 2, 2008. DOI: 10.1016/j.vaccine.2008.07.012.

Silica-Shelled Single Quantum Dot Micelles as Imaging Probes with Dual or Multimodality. Rumiana Bakalova, Zhivko Zhelev, Ichio Aoki, Hideki Ohba, Yusuke Imai, and Iwao Kanno. Analytical Chemistry. 2006, 78 (16) pp 5925–5932. July 14, 2006. DOI: 10.1021/ac060412b.

Multifunctional Separation Mechanism on Poly(oxyethylene) Stationary Phases in Capillary Liquid Chromatography. Toyohide Takeuchi and Lee Wah Lim. Analytical Sciences. 2010, 26 (9) pp 937-941. September 10, 2010. DOI: 10.2116/analsci.26.937.

N-Alkylated aminopyrazines for use as hydrophilic optical agents. Amruta R. Poreddy, Bethel Asmelash, Karen P. Galen, Richard M. Fitch, Jeng-Jong Shieh, James M. Wilcox, Tasha M. Schoenstein, Jolette K. Wojdyla, Kimberly R. Gaston, John N. Freskos, William L. Neumann, Raghavan Rajagopalan, Hyo-Yang Ahn, James G. Kostelc, Martin P. Debreczeny, Kevin D. Belfield, and Richard B. Dorshow. SPIE. Digital Library, Optical Molecular Probes and Industry. 2009. 7190. January 24, 2009. DOI: 10.1117/12.809287.

Reconstitution of the M13 Major Coat Protein and Its Transmembrane Peptide Segment on a DNA Template. Weijun Li, Itai Suez and Francis C. Szoka, Jr. ACS Biochemistry. 2007, 46 (29) pp 8579–8591. June 27, 2007. DOI: 10.1021/bi700165m.

Acid-degradable cationic methacrylamide polymerized in the presence of plasmid DNA as tunable non-viral gene carrier. In Kap Ko, Assem Ziady, Shiwei Lu, Young Jik Kwon. Biomaterials. 2008, 29 (28) pp 3872–3881. June 27, 2008. DOI: 10.1016/j.biomaterials.2008.06.003.

Electrostatic readout of DNA microarrays with charged microspheres. Nathan G Clack, Khalid Salaita, and Jay T Groves. Nature Biotechnology. 2008, 26 (7) pp 825-830. June 29, 2008. DOI: 10.1038/nbt1416.

Poly(ethylene oxide)-bonded stationary phase for capillary ion chromatography. Toyohide Takeuchi, Budhi Oktavia, Lee Wah Lim. Anal Bioanal Chem. 2009, 393(4) pp 1267-1272. November 30, 2008. DOI: 10.1007/s00216-008-2533-7.

An adsorption chromatography assay to probe bulk particle transport through hydrogels. I. Vladescu, O. Lieleg, S. Jang, and Katharina Ribbeck. Journal of Pharmaceutical Sciences. 2012, 101 (1) pp 436-442. September 8, 2011. DOI: 10.1002/jps.2273.

Biomolecular strategies for cell surface engineering. John Tanner Wilson. Smartech. 2008, December 5, 2008.

Investigations into Improving the Separation of PEGylated Proteins. Vita Knudson, Tividar Farkas, and Michael McGinley. Phenomenex, (TN-1034).

Stabilization of α-chymotrypsin upon PEGylation correlates with reduced structural dynamics. Jose A. Rodriguez-Martinez, Ricardo J. Sola, Betzaida Castillo, Hector R. Cintron-Colon, Izarys Rivera-Rivera, Gabriel Barletta, Kai Griebenow. Biotechnology and Bioengineering. 2008, 101 (6) pp 1142-1149. December 15, 2008. DOI: 10.1002/bit.22014.

Development of a widefield SERS imaging endoscope. Patrick Z. McVeigh, Rupananda J. Mallia, Israel Veilleux, Brian C. Wilson. SPIE Proceedings. 2012, 8217 (1) pp 1-6. February 13, 2012. DOI: 10.1117/12.907304.

Characterization of Particle Translocation through Mucin Hydrogels. Oliver Lieleg, Ioana Vladescu, and Katharina Ribbeck. Biophysical Journal. 2010, 98 (9) pp 1782–1789. May 5, 2010. DOI: 10.1016/j.bpj.2010.01.012.

Short polyethylene glycol chains densely bound to soft nanotube channels for inhibition of protein aggregation. N. Kameta, T. Matsuzawa, K. Yaoi, and M. Masuda. RSC Advances. 2016, 6 (43) pp 36744-36750. April 7, 2016. DOI: 10.1039/C6RA06793J.

Site directed Pegylation: Role of pH and temperature, to increase the productivity of insulin oligomer conjugate. Ashutosh Sudhir Naik, Koduru srivatsa, Krishnappa Mane, Phanichand Kodali, Laxmi Adhikary. Journal of Pharmaceutical and Biological Sciences. 2017, 5(4) pp 155-160. 2017.

Protease-triggered siRNA delivery vehicles. David B. Rozema, Andrei V. Blokhin, Darren H. Wakefield, Jonathan D. Benson, Jeffrey C. Carlson, Jason J. Klein, Lauren J. Almeida, Anthony L. Nicholas, Holly L. Hamilton, Qili Chu, Julia O. Hegge, So C. Wong, Vladimir S. Trubetskoy, Collin M. Hagen, Eric Kitas, Jon A. Wolff, and David L. Lewis. Journal of Controlled Release. 2017, 209 pp 57-66. 7/10/2015. DOI: 10.1016/j.jconrel.2015.04.012.

Multivalent Benzamidine Molecules for Plasmin Inhibition: Effect of Valency and Linker Length. Tanmaye Nallan Chakravarthula, Dr. Ziqian Zeng, Prof. Nathan J. Alves. ChemMedChem, Volume 17, Issue 22, (2022), 09/16/2022,

Applicable patents and legal notices are available at legal notices.

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