Theranostic system for ratiometric fluorescence monitoring of peptide-guided targeted drug delivery

Conjugation of an anticancer drug with a cancer-specific carrier and a fluorescent dye to form a theranostic system enables real time monitoring of targeted drug delivery (TDD). However, the fluorescence signal from the dye is affected by the light absorption and scattering in the body, photobleaching, and instrumental parameters. Ratiometric measurements utilizing two fluorescence signals of different wavelengths are known to improve sensitivity, reliability and quantitation of fluorescence measurements in biological media. Herein, a novel theranostic system comprising the anticancer drug chlorambucil (CLB), cancer-specific peptide octreotide amide (OctA), and a long-wavelength dual fluorescent cyanine dye IRD enabling ratiometric monitoring of drug delivery was developed and evaluated on the cancer cell line PANC-1.