Monoclonal antibody-based quantitation of poly(ethylene glycol)-derivatized proteins, liposomes, and nanoparticles

Tian Lu Cheng, Chiu Min Cheng, Bing Mae Chen, Der An Tsao, Kuo Hsiang Chuang, Sheng Wen Hsiao, Yi Hung Lin, Steve R. Roffler

Research output: Contribution to journalArticlepeer-review

83 Citations (Scopus)


Covalent attachment of poly(ethylene glycol) (PEG) molecules to drugs, proteins, and liposomes is a proven technology for improving their bioavailability, safety, and efficacy. Qualitative and quantitative analysis of PEG-derivatized molecules is important for both drug development and clinical applications. We previously reported the development of a monoclonal IgM antibody (AGP3) to PEG. We now describe a new IgG1 monoclonal antibody (E11) to PEG and show that it can be used in combination with AGP3 to detect and quantify PEG-derivatized molecules. Both antibodies bound the repeating subunits of the PEG backbone and could detect free PEG and PEG-modified proteins by ELISA, immunoblotting, and flow cytometry. Detection sensitivity increased with the length and the number of PEG chains on pegylated molecules. Both antibodies also efficiently accelerated the clearance of a PEG-modified enzyme in vivo. A sandwich ELISA in which E11/AGP3 were employed as the capture/detection antibodies was developed to detect PEG-modified proteins at concentrations as low as 1.2 ng/mL. In addition, the ELISA could also quantify, in the presence of 10% fetal bovine serum, free methoxy-PEG 20,000, PEG2,000-quantum dots, and PEG2,000- liposomes at concentrations as low as 20 ng/mL (1.0 nM), 1.4 ng/mL (3.1 pM), and 2.4 ng/mL (3.13 nM phospholipids), respectively. Finally, we show that the sandwich ELISA could accurately measured the in vivo half-life of a PEG-modified enzyme. These antibodies should be generally applicable to the qualitative and quantitative analysis of all PEG-derivatized molecules.

Original languageEnglish
Pages (from-to)1225-1231
Number of pages7
JournalBioconjugate Chemistry
Issue number5
Publication statusPublished - 2005
Externally publishedYes

ASJC Scopus subject areas

  • Bioengineering
  • Biotechnology
  • Biomedical Engineering
  • Pharmacology
  • Pharmaceutical Science
  • Organic Chemistry


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