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Carboxy-PEG-Lipoamide Compounds

A carboxylate, bidentate thiol polyethylene glycol compound for pegylating metal surfaces.

Pierce CL(PEG)12

Thermo Scientific Pierce CL(PEG)12, or carboxy-PEG12-lipoamide, is a carboxyl- and bidentate thiol-terminated compound that contains a 4-unit polyethylene glycol (PEG) spacer and is used to modify quantum dots, and silver or gold surfaces and particles.

CL(PEG)12 is a bidentate thiol-terminated and carboxylic acid pegylation reagent. The PEG compound has a defined molecular weight and spacer length and is useful for modifying surfaces such quantum dots, self-assembled monolayers and magnetic particles. Functionalization of solid surfaces with this polyethylene glycol reagent provides carboxylate "handles" for protein immobilization via EDC crosslinking and significantly reduces nonspecific protein binding and provides.


  • Metal-binding – terminal bidentate thiol reacts spontaneously with silver, gold and other metal surfaces to form strong dative bonds
  • Carboxylate – terminal carboxylic acid group allows conjugation to amine-containing affinity ligands using carbodiimide (EDC) and Sulfo-NHS crosslinking chemistry
  • Polyethylene glycol – PEG groups are flexible, non-immunogenic, hydrophilic, and significantly reduce nonspecific binding of surfaces for protein methods
  • Spacer arm – 12-unit PEG spacer makes the reagent nearly 56 angstroms long, minimizing steric hindrance for protein immobilization and binding assays

Product Details:

Carboxy-PEG12-lipoamide; CL(PEG)12

Chemical structure and properties of CL(PEG)12:

  • Alternative name: Carboxy-PEG12-Lipoamide
  • Chemical name: 45-(1,2-dithiolan-3-yl)-41-oxo-4,7,10,13,16,19,22,25,28,31,34,37-dodecaoxa-40-azapentatetracontan-1-oic acid
  • Chemical formula: C35H67NO15S2
  • Molecular weight: 806.03
  • Spacer arm: 55.5 angstroms
  • Form: yellow solid
  • Solubility: dissolve in DMSO or DMF for use

The use of CL(PEG)12 with ML(PEG)4 in surface modification can form a hydrophilic “lawn” of methyl ether-terminated PEGs with periodic exposed carboxy -containing PEGs. The exposed carboxylic acid groups can be coupled to affinity ligands using the carbodiimide coupling reaction with EDC and sulfo-NHS.

Pegylated metal surface with carboxy-PEG-lipoamide
Modification of metal surfaces with ML(PEG)4 and CL(PEG)12 pegylation reagents.

Typical PEG reagents contain heterogeneous mixtures of different PEG chain lengths; however, our PEG reagents are homogenous compounds of defined molecular weight and spacer length, providing precision in optimizing modification applications.

General References:

  1. Prime, K.L. and Whitesides, G.M. (1991). Self-assembled organic monolayers: model systems for studying absorption of proteins at surfaces. Science 252:1164.
  2. Bentzen, E.L., et al. (2005). Surface modification to reduce non-specific binding of quantum dots in live cell assays. Bioconjugate Chem 16:1488-94.
  3. Lin, P-C., et al. (2006). Ethylene glycol-protected magnetic nanoparticles for a multiplexed immunoassay in human plasma. Small 2(4):485-9.
  4. Zheng, M., et al. (2003). Ethylene glycol monolayer protected nanoparticles for eliminating nonspecific binding with biological molecules. J Am Chem Soc 125:7790-1.
  5. Verma, A. and Rotello, V.M. (2005). Surface recognition of biomacromolecules using nanoparticle receptors. Chem Commun 3:303-12.
  6. Kidambi, S., et al. (2004). Selective depositions on polyelectrolyte multilayers: self-assembled monolayers of m-dPEG acid as molecular template. J Am Chem Soc 126:4697-03.

Related Products:

Protein PEGylation technical guide (and PEG reagent selection guide)

Ordering Information
Product # Description Pkg. Size Instructions MSDS CofA Price
26135 CL(PEG)12
Formulation: 12-unit ethyleneglycol functionalized with carboxyl and bidentate thiol ends; solid
Sufficient For: 5mL of typical 1X (25mM) reaction solution
100mg Product Instructions for product #26135 CL(PEG)12 MSDS for product #26135 CL(PEG)12 Certificate of Analysis for product #26135 CL(PEG)12 $385.00

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Instructions | MSDS | CofA
Product Instructions | MSDS | CofA  

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