Fluorescence Lifetime Imaging for Characterization of Cancer Biomarkers: Application to HER2 Positive Tumors*

Advances in tumor biology created a foundation for targeted therapy aimed at inactivation of specific molecular mechanisms responsible for cell malignancy. In this paper, we used in vivo fluorescence lifetime imaging with HER2-targeted fluorescent probes as an alternative imaging method to investigate the efficacy of targeted therapy
We have designed an imaging system is a time-resolved fluorescence technique for calculating the lifetime of the contrast agent. HER2-specific Affibody (His6-ZHER2:GS-Cys) (Affibody, Stockholm, Sweden) conjugated with the Dylight750 fluorescent probe (Thermo-Fisher-Scientific, Waltham, Massachusetts) was used as contrast agent and six human cancer cell lines, known to express different levels of HER2/neu are used in athymic mice xenografts.
We have shown that HER2-specific Affibody conjugated with the Dylight750 fluorescent probe as contrast agent, we demonstrated in live animals that fluorescence lifetime of the bounded contrast agent can be used to assess the high to mid expression of HER2 expressing tumors in-vivo. This method can replace invasive , and in-vitro biopsies.