Self-Tracking Multifunctional Nanotheranostics for Sensitive miRNA Imaging Guided Photodynamic Therapy.

A theranostic system that enables monitoring the delivery process and amplified detection of low-abundance biomarkers is significant for bioimaging and biomedicine. We here develop a graphitic carbon nitride (g-C 3 N 4 ) nanosheet based self-tracking multifunctional nanotherapeutic system for sensitive miRNA guided photodynamic therapy in living cells. The g-C 3 N 4 nanosheets are employed not only as a nanocarrier for an intracellular hybridization chain reaction for sensitive miRNA imaging but also as an excellent photosensitizer for tumor therapy. Moreover, the fluorescent g-C 3 N 4 nanosheets allow assessing the transfection efficiency to mitigate the false negative signals. In vitro experiments showed that the proposed strategy had high signal amplification efficiency. The live cell studies revealed that the g-C 3 N 4 @H1/H2 could distinguish different miRNA expression levels from tumor to normal cells. The cell viability assay demonstrated the good photodynamic therapy efficiency of g-C 3 N 4 @H1/H2. Therefore, the developed self-tracking multifunctional nanotheranostics hold great potential for biomarker detection and imaging guided photodynamic therapy in living cells.