Fluorescent ABC-Triblock Polymer Nanocarrier for Cisplatin Delivery to Cancer Cells

Monitoring intracellular administration of non-luminescent anticancer drugs like cisplatin is a very challenging task in cancer research. Perylenebisimide (PBI) chromophore tagged fluorescent ABC-triblock polycaprolactone (PCL) nanoscaffold was engineered having carboxylic acid blocks for the chemical conjugation of cisplatin at the core and hydrophilic PEG blocks at the periphery. The amphiphilic ABC triblock Pt-prodrug was self-assembled into <200 nm nanoparticles and exhibited excellent shielding against drug detoxification by the glutathione (GSH) species in the cytosol. In vitro drug release studies confirmed that the Pt-prodrug was stable at extracellular conditions and the PCL block exclusively underwent lysosomal-enzymatic biodegradation at the intracellular level to release the cisplatin drug in the active-form for accomplishing more than 90% cell growth inhibition. Confocal microscopic imaging of the red-fluorescence signals from the perylene chromophores established the simultaneous monitoring and delivery aspects of the Pt-prodrug, and the proof-of-concept was successfully demonstrated in breast and cervical cancer cell lines.