Chemiluminescent PEG-PCL micelles for imaging hydrogen peroxide

Hydrogen peroxide is one of the fundamental molecules of biology, regulating key cell signaling pathways and the development of numerous inflammatory diseases. There is therefore great interest in developing contrast agents that can detect hydrogen peroxide in vitro and in vivo. In this report, we present a new contrast agent for imaging hydrogen peroxide, termed the chemiluminescent poly(ethylene glycol)-b-poly(epsilon-caprolactone) (PEG-PCL) micelles (CPMs), which can detect hydrogen peroxide at nanomolar concentrations and chemiluminesce in the near IR range (676 nm) in the presence of hydrogen peroxide. The CPMs are composed of a PEG-PCL scaffold and have fluorescent dyes and peroxalate esters in their hydrophobic PCL core. The CPMs image hydrogen peroxide by undergoing a three-component chemiluminescent reaction involving a peroxalate ester, a fluorescent dye, and hydrogen peroxide. The CPMs also have a stealth PEG corona to enhance their circulation half life. The CPMs should find numerous applications for imaging hydrogen peroxide because of their nanomolar sensitivity, small size, and stealth pegylated surface. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res 89A: 561-566, 2009