Photodynamic therapy with hyperbranched poly(ether-ester) chlorin(e6) nanoparticles on human tongue carcinoma CAL-27 cells

SummaryBackgroundHyperbranched polymers represent a new class of drug-delivery vehicle that can be used to prepare nanoparticles with uniform size distribution.MethodsIn this study we prepared covalent conjugates between the photosensitizer chlorin(e6) and hyperbranched poly(ether-ester), HPEE. HPEE–ce6 nanoparticles were synthesized by carbodiimide-mediated reaction between HPEE and ce6, and characterized by ultraviolet–visible absorption spectroscopy (UV–Vis), and transmission electron microscopy (TEM). The uptake and phototoxicity of HPEE–ce6 nanoparticles towards human oral tongue cancer CAL-27 cells was detected by confocal laser scanning microscopy (CLSM) and MTT assay, respectively.ResultsThe absorption peak of HPEE–ce6 nanoparticles was red-shifted 12-nm compared with ce6, and TEM showed uniform nanoparticles with a diameter of 50-nm. HPEE–ce6 nanoparticles were taken up by CAL-27 cells after 4 h incubation and localized in the cytoplasm. The MTT assay showed a significantly (P < 0.05) higher phototoxicity compared to free ce6 after 12 J/cm2 of 660-nm laser illumination.ConclusionsThis is the first time to our knowledge that hyperbranched polymers have been used in PDT drug delivery.