In vivo multifunctional fluorescence imaging using liposome-coated lanthanide nanoparticles in near-infrared-II/IIa/IIb windows

In vivo fluorescence imaging in the near-infrared II window (NIR-II, 1000–1700 nm) has great improvements in imaging quality compared with the visible (400–700 nm) and the NIR-I (700–900 nm) window due to the low autofluorescence and the reduced scattering. To date, a variety of NIR-II fluorophores have been synthesized and applied in vivo imaging and disease diagnosis. Multifunction is believed as one of the developing trends. In this study, we report a liposome-coated lanthanide nanoparticle, named as NPs@Lips, which can emit three-wavelengths fluorescence (1000–1100 nm (NIR-II), 1300–1350 nm (NIR-IIa), 1500–1700 nm (NIR-IIb) simultaneously under an 808 nm laser excitation. The imaging results demonstrated that the images in longer wavelengths provided a higher resolution and enhanced signal-to-noise (S/N) ratio than the ones in shorter wavelengths. Then, the NPs@Lips were studied for in vivo multifunctional biological imaging, including brown adipose tissue imaging, vascular imaging and lymph node localization biopsy. Interestingly, NPs@Lips can accumulate in brown adipose tissue without any targeting molecules, which provided an alternative sensitive and non-radiation method for brown adipose tissue imaging in the field of metabolic disorders. Overall, the NPs@Lips were potential NIR-II probe for multifunctional nanomedicine applications.