Construction and In Vitro Validation of Liposomes Loaded with ROS-Responsive Probe QM-CF

In this study, liposomes loaded with the reactive oxygen species-responsive probe QM-CF (Lipo@QM-CF) were prepared using a phospholipid composition consisting of dipalmitoylphosphatidylcholine (DPPC), sphingomyelin (SM), cholesterol (CHO), DSPE-PEG2000, and DSPE-PEG2000-maleimide, selected for their roles in membrane stability, fluidity, and potential for functional modification. The particle size, stability, encapsulation efficiency, and probe loading status of the liposomes were preliminarily investigated. The results showed that the prepared liposomes exhibited uniform particle size (approximately 160–170 nm, PdI < 0.15) and showed no significant changes in particle size during 21 days of storage at 4°C, indicating good in vitro stability. Elemental analysis revealed that chlorine signals colocalized with the liposome positions, suggesting the colocalization of QM-CF with liposomes. Chemiluminescence imaging further verified the probe loading status: free QM-CF exhibited luminescence only in methanol, while Lipo@QM-CF showed no luminescence but recovered upon methanol demulsification, with further enhancement in the presence of reactive oxygen species, confirming that QM- CF was successfully encapsulated within liposomes and possessed good ROS-responsive release capability. This study successfully demonstrates the construction of a liposome-based probe for ROS imaging, offering a novel strategy for detecting inflammatory microenvironments.