Lipoamido-dPEG®₂₄-TFP ester




Lipoamido-dPEG®24-TFP ester, product number 10643, is a monodispersed, crosslinking PEGylation reagent that joins free amines to metal surfaces. The single molecular weight, discrete-chain-length polyethylene glycol (dPEG®) product consists of alpha-lipoic acid and a 2,3,5,6-tetrafluorophenol (TFP) ester on opposite ends of a dPEG® spacer. The lipoic acid group forms two (2) coordinate covalent bonds (dative bonds) with metal, especially gold and silver. The TFP ester reacts with free amines to form amide bonds. Applications for this product include peptide or protein immobilization on metal surfaces, the formation of self-assembled monolayers (SAMs) on metal surfaces, and sensor development.

What is the dPEG® difference?

Traditional PEGylation reagents are dispersed (non-uniform) polymers. These products consist of a broad range of PEG chain lengths and molecular weights in a Poisson distribution. This mixture of different PEG products adds analytical complexity (and, hence, time and money) to the characterization of conjugates made with traditional PEG polymers.

In contrast, Quanta BioDesign’s dPEG® products are single molecular weight PEGs with discrete chain lengths. Each dPEG® product consists of one PEG molecular weight and chain length. We synthesize all of our dPEG® products from high purity starting materials using proprietary processes that assure the highest quality reagents for your work. The single molecular weight and discrete chain length of our products reduce the analytical complexity of conjugates made with dPEG® reagents, thus saving time and money. In other words, our customers gain all of the benefits of PEG without the headaches that come with using dispersed polymers. We call these benefits, “the dPEG® difference.”

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What is dPEG®?

Frequently Asked Questions (about dPEG® products)

Lipoic Acid-containing dPEG® Products

Lipoic acid, also known as alpha-lipoic acid, α-lipoic acid, and thioctic acid, is a naturally occurring antioxidant that functions as a cofactor in several enzyme systems. Lipoic acid consists of a dithiolane ring (a five-membered ring containing a disulfide) attached to a pentanoic acid group.

Lipoic acid is a bidentate thiol ligand that forms two stable dative bonds per lipoic acid group with gold, silver, and other metals. These dative bonds form with oxidized lipoic acid or reduced dihydrolipoic acid (DHLA). Because it forms two dative bonds on metal surfaces, lipoic acid is more stable than PEGylation reagents containing a single thiol. This increased stability prevents lipoic-acid-functionalized dPEG® products from being oxidized off the metal surface.

Using Lipoamido-dPEG®24-TFP ester

When using this product, it is typical to begin with the conjugation of the carboxyl end of the dPEG® to an amino group to form an amide bond. TFP esters react more readily with amines and possess better hydrolytic stability than N-hydroxysuccinimide (NHS). The superiority of PEG-TFP esters over NHS esters is documented in the scientific literature and by Quanta BioDesign’s in-house research. TFP esters optimally react with amines at pH 7.5 – 8.0. However, they also will react with amines at pH values above and below this range.

After reacting the TFP ester end of the molecule, the lipoic acid end of the dPEG® linker can be reacted with metals such as gold or silver. The lipoic acid group forms dative bonds with metals with or without reduction to DHLA. If reduction to DHLA is preferred, Tris(2-carboxyethyl)phosphine (TCEP) will reduce lipoic acid to DHLA rapidly.

Lipoamido-dPEG®24-TFP ester dissolves in water or aqueous buffer and organic solvents. Stock solutions in water or aqueous buffer do not have long-term stability and should be used immediately. For stock solutions with long-term stability, we recommend dry (over 3 Å molecular sieves) water-miscible solvents such as N, N-dimethylacetamide (DMAC) or acetonitrile. Unused stock solutions should be stored at -20°C or colder.

Bulk Quantities Are Available

If you need a larger quantity of Lipoamido-dPEG®24-TFP ester than our standard package sizes, please contact us for a quote. Our commercial capabilities permit us to manufacture this product at any scale that you need.

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Our dPEG® products are different from conventional PEGylation reagents. To discover the dPEG® difference, please click the “Add to Cart” button now.

Additional information

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