Size-selected graphene oxide loaded with photosensitizer (TMPyP) for targeting photodynamic therapy in vitro

Abstract

Targeted therapies of various diseases are nowadays widely studied in many biomedical fields. Photodynamic therapy (PDT) represents a modern treatment of cancer using a locally activated light. TMPyP is an efficient synthetic water-soluble photosensitizer (PS), yet with poor absorption in the visible and the red regions. In this work, we prepared size-selected and colloidally stable graphene oxide (GO) that is appropriate for biomedical use. Thanks to the negative surface charge of GO, TMPyP was easily linked in order to create conjugates of GO/TMPyP by electrostatic force. Due to the strong ionic interactions, charge transfers between GO and TMPyP occur, as comprehensively investigated by steady-state and time-resolved fluorescence spectroscopy. Biocompatibility and an in vitro effect of GO/TMPyP were confirmed by a battery of in vitro tests including MTT, comet assay, reactive oxygen species (ROS) production, and monitoring the cellular uptake. PDT efficiency of GO/TMPyP was tested using 414 and 740 nm photoexcitation. Our newly prepared nanotherapeutics showed a higher PDT effect than in free TMPyP, and is promising for targeted therapy using clinically favorable conditions.