Preparation and characterization of the second near-infrared window fluorescent/photoacoustic imaging liposomes

The second near-infrared window(NIR-II)fluorescent dye IR-1061 has the disadvantage of poorwater solubility and low quantum yield, which limits its application in biomedicine. We used liposomes as the carrier to increase their water solubility, and co-loaded a near-infrared region(NIR-I)fluorescent dye IR-780 into liposomes to enhance the fluorescence intensity of IR-1061 in NIR-II. Results showed that the liposomes exhibited significantly enhanced characteristic fluorescence under 980 nm laser irradiation. In addition, particle size, appearance, photothermal conversion efficiency, photoacoustic performance and cytotoxicity of liposomes were examined. This study showed that these combined liposomes exhibited potential as a NIR-II fluorescence/photoacoustic bimodal imaging system for the diagnosis and guidance of tumor photothermal therapy.