Expression and significance of quantum dots in RAW 264.7 macrophages

The aim of the present study was to investigate the clinical application and utility of CdSe/ZnS quantum dots (QDs) in tracing RAW 264.7 macrophages. RAW 264.7 cells and QDs at various concentrations were co-cultured for 24 h, and the fluorescence intensity of the macrophages was determined at various time points. The mRNA expression levels of genes encoding inflammatory cytokines [tumor necrosis factor (TNF)-α and interleukin (IL)-1β] were determined, and cellular assays were performed to investigate the activation, proliferation and apoptosis of RAW 264.7 cells. The QDs were engulfed by the macrophages, and the fluorescence intensity of RAW 264.7 cells increased with increasing concentration and time. The IL-1β mRNA level increased significantly at 50 µg/ml QDs, and that of TNF-α increased significantly at 100 µg/ml QDs. Accelerated proliferation of RAW 264.7 cells was observed at 50 and 100 µg/ml QDs; however, no increase in apoptosis of RAW 264.7 cells was observed in co-culture. CdSe/ZnS QDs may be used as tracers due to the fluorescence intensity of RAW 264.7 cells increasing with increasing QD concentration and time, resulting in the activation of macrophages and significant increases in proliferation at 50 and 100 µg/ml QDs compared with in the absence of QDs. The change in QD concentration was not significantly associated with the proliferation and apoptosis of RAW 264.7 macrophages.