A multi-functional fluorescent scaffold as a multi-colour probe: design and application in targeted cell imaging

A novel scaffold material based on a novel targeting strategy has been developed, benefiting from recent progress in the development of fluorescent bioprobes. This concept suggests that several specifications which are desired for cancer cell targeting and imaging studies can be satisfied at the same time in one multifunctional scaffold. Besides, such scaffolds exhibit multi-colour properties when combined with a targeting moiety. For this purpose, a fluorescent and functional monomer, 3-(1H-phenanthro[9,10-d] imidazol-2-yl) phenol (PIP) and an antibody labelling kit (CF555) were merged on the same scaffold to generate the proposed bioprobe. This design offers multicolour cell images by emitting at dual wavelengths with no quenching in its fluorescent property. Also, pendant alcohol groups in the structure of PIP enable covalent attachment to labelled protein, CF555/anti-CD44 in order to enhance the biological activity and specificity towards the target. After combining with the targeting moiety, the bioconjugate was characterized, tested for in vitro studies, and the cellular internalization was monitored in live cells via the fluorescence microscope technique. The present work with such a strategy explores the potential use of the proposed fluorescent probe for the first time. The aim is to achieve targeted imaging of CD44 positive U87-MG cancer cells and determine specific cellular labelling via fluorescence imaging and flow cytometry experiments.