Preparation of a Dithiol-Reactive Probe for PET Imaging of Cell Death

Conjugates of 4-(N-(S-glutathionylacetyl)amino)phenylarsonous acid (GSAO) with optical or radionuclide probes are able to image cell death in vivo. GSAO conjugates are retained in the cytosol of dying and dead cells via the formation of covalent bonds between the As(III) ion and the thiol groups of proximal cysteine residues. Here, we describe the method for preparing a NODAGA-GSAO conjugate (hereafter referred to as cell death indicator, CDI-DX001) and its radiolabeling with gallium-68 (⁶⁸Ga-CDI-DX001) for positron emission tomography (PET) imaging of cell death.