Related Experiment Video
Updated: Aug 12, 2025
A Bright NIR-II Fluorescence Probe for Vascular and Tumor Imaging
Published on: March 17, 2023
Low-Dose NIR-II Preclinical Bioimaging Using Liposome-Encapsulated Cyanine Dyes
Duyang Gao1, Zichao Luo2, Yang He3
1Paul C. Lauterbur Research Center for Biomedical Imaging, CAS Key Laboratory of Health Informatics, Shenzhen Key Laboratory of Ultrasound Imaging and Therapy, Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China.
Abstract:
Fluorescence imaging in the second near-infrared window (NIR-II, 1000-1700 nm) provides a powerful tool for in vivo structural and functional imaging in deep tissue. However, the lack of biocompatible contrast agents with bright NIR-II emission has hindered its application in fundamental research and clinical trials. Herein, a liposome encapsulation strategy for generating ultrabright liposome-cyanine dyes by restricting dyes in the hydrophobic pockets of lipids and inhibiting the aggregation, as corroborated by computational modeling, is reported. Compared with free indocyanine green (ICG, an US Food and Drug Administration-approved cyanine dye), liposome-encapsulated ICG (S-Lipo-ICG) shows a 38.7-fold increase in NIR-II brightness and enables cerebrovascular imaging at only one-tenth dose over a long period (30 min). By adjusting the excitation wavelength, two liposome-encapsulated cyanine dyes (S-Lipo-ICG and S-Lipo-FD1080) enable NIR-II dual-color imaging. Moreover, small tumor nodules (2-5 mm) can be successfully distinguished and removed with S-Lipo-ICG image-guided tumor surgery in rabbit models. This liposome encapsulation maintains the metabolic pathway of ICG, promising for clinical implementation.
