Cd^125mTe/ZnS Nanoparticles coupled with anti-thrombomodulin monoclonal antibody 201B

Cd^125mTe/ZnS nanoparticles consist of Cd^125mTe cores capped with ZnS to prevent particle degradation and to reduce leaching of ^125mTe (t_1/2 = 58 days, x-ray = 27–30 keV, and gamma ray = 35.5 keV) into blood stream and tissues. They can be derivatized for conjugation with biomolecules, such as peptides, antibodies, nucleic acids, and small organic compounds for in vitro and in vivo studies. Cd^125mTe/ZnS nanoparticles have a diameter of ~5 nm. There have been limited in vivo studies of the toxicological and pharmacological profiles of Cd^125mTe/ZnS in small animals (1). Thrombomodulin (CD141 or BDCA-3) is an integral membrane receptor protein expressed on the surface of endothelial cells (2). Thrombin binds to thrombomodulin to participate in coagulation, inflammation, and cancer (3). Monoclonal antibody (mAb) 201B against mouse lung thrombomodulin has been coupled to Cd^125mTe/ZnS nanoparticles for single-photon emission computed tomography (SPECT) biodistribution studies in mice (4).