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Lipoamido-dPEG®₁₂-acid (QBD-10808)



Lipoamido-dPEG®12-acid, product number QBD-10808, is a single molecular weight, discrete PEG (dPEG®) surface modification reagent for metal surfaces, especially gold and silver. The hydrophilic dPEG®12 spacer is 48 atoms (55.5 Å) long. The lipoamide moiety rapidly forms stable dative bonds with gold or silver. Using a carbodiimide such as EDC and an acylating agent such N-hydroxysuccinimide (NHS), the propionic acid group will react with free amines to form amide bonds. The water-soluble, non-immunogenic dPEG® spacer adds hydrodynamic volume to conjugates made with this product. For circulating nanoparticles, the increased hydrodynamic volume reduces or eliminates opsonization and facilitates a longer circulation time in vivo.

Lipoic acid, also known as thioctic acid and alpha-lipoic acid (ALA), is an organosulfur compound used by cells as an essential cofactor. The sulfur atoms at positions C6 and C8 form a disulfide bond in a five (5)-membered ring. Like other thiol products, lipoic acid readily forms dative bonds with gold, silver, and other metals. Because two dative bonds form for each molecule of lipoic acid, the thiol-metal dative bond is more stable than dative bonds formed with compounds containing one free thiol atom. Lipoic acid exists typically in an oxidized (closed ring) state. It is readily reduced to an open ring state called dihydrolipoic acid (DHLA) using tris(2-carboxyethyl)phosphine (TCEP) or other reducing agents.


Unit Size100mg, 1000mg
Molecular Weight806.03; single compound
Chemical formulaC₃₅H₆₇NO₁₅S₂
Purity> 98%
SpacersdPEG® Spacer is 48 atoms and 55.5 Å
Typical solubility properties (for additional information contact Customer Support)Methylene chloride, DMAC, DMSO, limited solubility in acetonitrile and water.
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, 2nd Edition, Elsevier Inc., Burlington, MA 01803, April, 2008 (ISBN-13: 978-0-12-370501-3; ISBN-10: 0-12-370501-0), pp. 188-190, 458-497, 924-935.

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.

Gold Coated Lanthanide Phosphate Nanoparticles for Targeted Alpha Generator Radiotherapy. Mark F. McLaughlin, Jonathan Woodward, Rose A. Boll, Jonathan S. Wall, Adam J. Rondinone, Stephen J. Kennel, Saed Mirzadeh, J. David Robertson. PLoS ONE 2012 8 (1) e54531January 18, 2013. DOI:10.1371/journal.pone.0054531.

PEGylated Luminescent Gold Nanoclusters: Synthesis, Characterization, Bioconjugation, and Application to Oneand Two-Photon Cellular Imaging. Eunkeu Oh, Fredrik Fatemi, Marc Currie, James B. Delehanty, Thomas Pons, Alexandra Fragola, Sandrine L´evˆeque-Fort, Ramasis Goswami, Kimihiro Susumu, Alan L. Huston, and Igor L. Medintz. Particle & Particle Systems Characterization 2013, (30), pp 1-13. February 5, 2013. DOI: 10.1002/ppsc.201200140.

Gastrointestinal Bioavailability of 2.0 nm Diameter Gold Nanoparticles. Candice A. Smith, Carrie A. Simpson, Ganghyeok Kim, Carly J. Carter, and Daniel L. Feldheim. ACS Nano. 2013, 7 (5) pp 3991–3996. April 21, 2013. DOI: 10.1021/nn305930e.

Directed self-assembly of proteins into discrete radial patterns. Garima Thakur, Kovur Prashanthi and Thomas Thundat. Science Reports. 2013, 1923 (3) May 30, 2013. DOI: 10.1038/srep01923.

Applicable patents and legal notices are available at legal notices.

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