Graphene quantum dots-loaded macrophages as a biomimetic delivery system for bioimaging and photodynamic therapy

Macrophages have been recommended for site-specific tumoral delivery of genes, drugs, or nanoparticles. Graphene quantum dots (GQDs) are a well-known fluorescence-based diagnosis and photodynamic therapy (PDT) agent. Herein, we determined the therapeutic efficacy of hybrid GQD-loaded macrophages in a 3D culture model and a xenograft mouse model of human lung cancer cells. We examined the PDT efficacy of hybrid GQD-loaded macrophages in both models using LED light. Cell viability assay showed that the LED light-based PDT induced cell death via GQDs. Reactive oxygen species and Ca²⁺ detection assays indicated that GQD-loaded macrophages induced apoptosis in the in vitro 3D culture model. In vivo fluorescence bioimaging and ex vivo fluorescence images of major organs (the kidney, liver, lung, spleen, and tumor) revealed a tumor-homing effect of GQD-loaded macrophages in the xenograft mouse model. Our results demonstrated that hybrid GQD-loaded macrophages are a promising biomimetic delivery system for bioimaging and cancer therapy.