Localization of tumor by chemiluminescence probe during photosensitization action

As a chemiluminescence (CL) probe, 3,7-dihydro-6-{4-{2-(N′-(5-fluoresceinyl) thioureido)ethoxy}phenyl}-2-methylimidazo{1,2-a}pyrazin-3-one dosium salt (FCLA) can sensitively and specifically react with singlet oxygen (1O2) and superoxide (O2−). Based on the fact that photosensitization action involves 1O2 generation, this report presents a novel method for localization of tumor mediated by FCLA. In experiments, FCLA was used as an optical reporter of 1O2 produced from photosensitization reaction of hematoporphyrin derivative. The effects of azide inhibition and deuterium enhancement on photosensitized CL indicated that 1O2 molecules generated during photosensitization action could be measured and imaged. In vivo experiments in vivo with tumor-bearing nude mice showed a clear CL image of tumor. The study suggests that CL imaging method may be applicable to the detection of 1O2 and the diagnosis of superficial tumors.