Vector Laboratories is closed for the President’s Day on Monday, February 19th. We will be back in the office on Tuesday, February 20th.
We will respond to emails upon our return. Have a wonderful day.

Azido-dPEG®₄-NHS ester (QBD-10501)



Azido-dPEG®4-NHS ester, product number QBD-10501, contains an azide group linked to an N-hydroxysuccinimidyl (NHS) ester through a single molecular weight, discrete polyethylene glycol (dPEG®) spacer. This product works with copper(I)-catalyzed, ruthenium-catalyzed click chemistry, and copper-free (e.g., strain-promoted) click chemistry. The dPEG® spacer imparts water solubility and adds hydrodynamic volume to the conjugated product. The single molecular weight product design, with its discrete chain length, simplifies analysis of this product.

NHS esters are the most popular, most widely used way to conjugate carboxylic acids to primary or secondary amines resulting in stable amide bonds. NHS esters react quickly and efficiently in aqueous media at physiological pH values (7.0 – 7.5). However, they are prone to hydrolysis over time. Moreover, the rate of hydrolysis is pH dependent. Consequently, they must be used immediately upon dissolution in water or aqueous buffer. Published research has shown that 2,3,5,6-tetrafluorophenyl (TFP) esters are more hydrolytically stable and have better reactivity with amines than NHS esters.


Unit Size100 mg, 1000 mg
Molecular Weight388.37; single compound
Chemical formulaC₁₅H₂₄N₄O₈
Purity> 98%
SpacersdPEG® Spacer is 16 atoms and 17.7 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.

Chemoselective Immobilization of Peptides on Abiotic and Cell Surfaces at Controlled Densities. Venkata R. Krishnamurthy, John T. Wilson, Wanxing Cui, XueZheng Song, Yi Lasanajak, Richard D. Cummings, and Elliot L. Chaikof. Langmuir. 2010, 26 (11) pp 7675-7678. May 7, 2010. DOI: 10.1021/la101192v.

Constant-speed vibrational signaling along polyethylene glycol chain up to 60-Å distance. Zhiwei Lin and Igor V. Rubtsov. PNAS. 2012, 109 (5) pp 1413-1418. January 31, 2012. DOI:10.1073/pnas.1116289109.

Ballistic energy transport along PEG chains: distance dependence of the transport efficiency. Zhiwei Lin , Nan Zhang , Janarthanan Jayawickramarajah and Igor V. Rubtsov. Physical Chemistry Chemical Physics. 2012, 30 (14) pp 10445-10454. April 12, 2012. DOI: 10.1039/C2CP40187H.

An Intein-Mediated Site-Specific Click Conjugation Strategy for Improved Tumor Targeting of Nanoparticle Systems. Drew R. Elias, Dr. Zhiliang Cheng, and Prof. Andrew Tsourkas. Small. 2010, 6 (21) pp 2460–2468 November 5, 2010. DOI:10.1002/smll.201001095.

Peptide-Targeted Nanoglobular Gd-DOTA Monoamide Conjugates for Magnetic Resonance Cancer Molecular Imaging. Mingqian Tan, Xueming Wu, Eun-Kee Jeong, Qianjin Chen, and Zheng-Rong Lu. Biomacromolecules. 2010, 11 (3) pp 754–761. March 8, 2010. DOI:10.1021/bm901352v.

Protein addressing on patterned microchip by coupling chitosan electrodeposition and ‘electro-click’ chemistry. Xiao-Wen Shi,, Ling Qiu, Zhen Nie, Ling Xiao, Gregory F Payne and Yumin Du. Biofabrication. 2013, (5) 041001 pp 7. September 23, 2013. DOI:10.1088/1758-5082/5/4/041001.

Clickable Poly(ethylene glycol)-Microsphere-Based Cell Scaffolds. Peter K. Nguyen, Christopher G Snyder, Jason D. Shields, Amanda W. Smith, Donald L. Elbert. Macromolecular Journals. 2013, 214 (8) pp 948-956. March 4, 2013. DOI: 10.1002/macp.201300023.

Nano-Scale Alignment of Proteins on a Flexible DNA Backbone. Tatsuya Nojima1, Hiroki Konno, Noriyuki Kodera, Kohji Seio, Hideki Taguchi, Masasuke Yoshida. PLoS ONE. 2012, 7(12): e52534. December 26, 2012. DOI:10.1371/journal.pone.0052534.

A Mild and Reliable Method to Label Enveloped Virus with Quantum Dots by Copper-Free Click Chemistry. Jian Hao, Li-Li Huang, Rui Zhang, Han-Zhong Wang and Hai-Yan Xie. Analytical Chemistry. 2012, 84 (19) pp 8364−8370. September 4, 2012. DOI: org/10.1021/ac301918t.

ADIBO-Based ”Click” Chemistry for Diagnostic Peptide Micro-Array Fabrication: Physicochemical and Assay Characteristics. Denis Prim, Fabien Rebeaud, Vincent Cosandey, Roger Marti, Philippe Passeraub and Marc E. Pfeifer. ADIBO-Based ”Click” Chemistry for Diagnostic Peptide Micro-Array Fabrication: Physicochemical and Assay Characteristics. Denis Prim, Fabien Rebeaud, Vincent Cosandey, Roger Marti, Philippe Passeraub and Marc E. Pfeifer. Molecules. 2013, 18 pp 9833-9849. August 16, 2013. DOI: 10.3390/molecules18089833.

Bio-Inspired Liposomal Thrombomodulin Conjugate through Bio-Orthogonal Chemistry. Hailong Zhang, Jacob Weingart, Rui Jiang, Jianhao Peng, Qingyu Wu, and Xue-Long Sun. Bioconjugate Chemistry. 2013, 24 (4) pp 550–559. March 4, 2013. DOI: 10.1021/bc300399f.

Design and synthesis of glycoprotein-based multivalent glyco-ligands for influenza hemagglutinin and human galectin-3. Helen Wanga, Wei Huang, Jared Orwenyo, Aditi Banerjee, Gerardo R. Vasta, Lai-Xi Wang. Bioorganic & Medicinal Chemistry. 2013, 21 (7) pp 2037–2044. April 1, 2013. DOI: 10.1016/j.bmc.2013.01.028.

A Method for Determining Small Anharmonicity Values from 2DIR Spectra Using Thermally Induced Shifts of Frequencies of High-Frequency Modes. Zhiwei Lin , Patrick Keiffer , and Igor V. Rubtsov. Journal of Physical ChemistryB. 2011, 115 (18) pp 5347-5353. December 28, 2010. DOI: 10.1021/jp1094189.

3D Tumor tissue analogs and their orthotopic implants for understanding tumor-targeting of microenvironment-responsive nanosized chemotherapy and raditation. Pallavi Sethi, PhD., Amar Jyoti, PhD, Elden P. Swindell, PhD, Ryan Chan, PharmD, Ulrich W. Langner, DABR, PhD, Jonathan M. Feddock, MD, Radhakrishnan Nagarajan, PhD, Thomas V. O’Halloran, PhD, Meenakshi Upreti, PhD. Nanomedicine. 2015, 11 (8) pp 2013-2023. July 22,2015. DOI: 10.1016/j.nano.2015.07.013.

Click Chemistry Applied to the Synthesis of Salmonella Typhimurium O-Antigen Glycoconjugate Vaccine on Solid Phase with Sugar Recycling. Giuseppe Stefanetti, Allan Saul, Calman A. MacLennan and Francesca Micoli. Bioconjugate Chemistry. 2015. November 9, 2015. DOI: 10.1021/acs.bioconjchem.5b00521.

Energy Transport in PEG Oligomers: Contributions of Different Optical Bands. Layla N Qasim, Arkady A Kurnosov, Yuankai Yue, Zhiwei Lin, Alexander L Burin, and Igor V Rubtsov. The Journal of Physical Chemistry. 2016, October 31, 2016. DOI: 10.1021/acs.jpcc.6b09389.

Streptavidin-hydrogel prepared by sortase A-assisted click chemistry for enzyme immobilization on an electrode. Takuya Matsumoto, Yuki Isogawa, Tsutomu Tanaka, and Akihiko Kondo. Biosensors and Bioelectronics. 2017, 99 (2018) pp 56-61. July 17, 2017. DOI:

Lysosomal Targeting Enhancement by Conjugation of Glycopeptides Containing Mannose-6-phosphate Glycans Derived from Glyco-engineered Yeast. Ji-Yeon Kang, Keun Koo Shin, Ha Hyung Kim, Jeong-Ki Min, Eun Sun Ji, Jin Young Kim, Ohsuk Kwon, & Doo-Byoung Oh. Scientific Reports. 2018, 8 (8730) pp 1-14. June 7, 2018. DOI: 10.1038/s41598-018-26913-4.

Streptavidin-hydrogel prepared by sortase A-assisted click chemistry for enzyme immobilization on an electrode. Takuya Matsumoto, Yuki Isogawa, Tsutomu Tanaka, and Akihiko Kondo. Biosensors and Bioelectronics. 2018, 99 pp 56-61. 1/15/2018. DOI: 10.1016/j.bios.2017.07.044.

Antibody Targeted PET Imaging of 64Cu-DOTA-Anti-CEA PEGylated Lipid Nanodiscs in CEA Positive Tumors. Patty Wong, Lin Li, Junie Chea, Weidong Hu, Erasmus Poku, Todd Ebner, Nicole Bowles, Jeffrey Y. C. Wong, Paul J. Yazaki, Stephen Sligar, John E. Shively. Bioconjugate Chem. 2020, 31, 3, 743-753 January 21, 2020 DOI:

Click chemistry compared to thiol chemistry for the synthesis of site-selective glycoconjugate vaccines using CRM197 as carrier protein. G. Stefanetti, M. Allan, A. Usera, F. Micoli. Glycoconjugate Journal (2020). June 13, 2020. DOI: 10.1007/s10719-020-09930-2

NIR Photodynamic Destruction of PDAC and HNSCC Nodules Using Triple-Receptor-Targeted Photoimmuno-Nanoconjugates: Targeting Heterogeneity in Cancer. Bano, S.; Obaid, G.; Swain, J.W.R.; Yamada, M.; Pogue, B.W.; Wang, K.; Hasan, T.. J. Clin. Med. 2020, 9, 2390

Photodynamic priming with triple-receptor targeted nanoconjugates that trigger T cell-mediated immune responses in a 3D in vitro heterocellular model of pancreatic cancer, Pushpamali De Silva ORCID, Shazia Bano ORCID, Brian W. Pogue, Kenneth K. Wang, Edward V. Maytin and Tayyaba Hasan, Nanophotonics, 2021, Volume 10 Issue 12, DOI: 10.1515/nanoph-2021-0304

Applicable patents and legal notices are available at legal notices.

How do I Request a Quote?

To request a quote for products:

  1.  Log in to
  2.  Add the items you wish to quote to the cart;
  3.  View your cart;
  4.  Click on the “Request a Quote” button found below the items in your cart;
  5.  Download your quote