Tracking the polarity changes of asthmatic mice by fluorescence imaging

Abstract Exploring the changes in the polarity of lipid droplets (LDs) in the lungs of asthma patients is of great significance for the detection and treatment of asthma. For this reason, we have synthesized a powerful polarity-sensitive fluorescent probe LW-1 targeting LDs, which was constructed with pyrene as the fluorophore and malononitrile as the electron withdrawing group. Due to its special intramolecular charge transfer mechanism, the probe exhibits strong solvatochromic response toward polarity. With the assistance of LW-1, we not only successfully distinguished cancer cells from normal cells but also detected the changes of LDs polarity under the stimulation of starvation, oleic acid and hydrogen peroxide. Moreover, the polarity changes of LDs in lungs of asthma mice were successfully monitored at organ and tissue levels, and revealed for the first time that lung polarity is reduced in asthmatic conditions. In addition, the therapeutic efficacy of ketotifen fumarate for asthmatic mice has also been successfully tracked by monitoring LDs polarity, confirming the potential of LW-1 medical applications. This work provides a new perspective for asthma research, and will inspire more strategies for clinical diagnosis and the development of new asthma drugs.