Lipid droplet-targetable fluorescent probe for imaging viscosity in PM2.5 exposure-induced lung injury, non-alcoholic fatty liver, and tumor models

Elucidating the intrinsic relationship between viscosity and lipid droplet (LD)-related diseases remains challenging, due to the lack of sufficient attention and effective tools. So far, the visualization of abnormal LD viscosity in PM 2.5 exposure-induced lung injury model, and malignant tumor tissues containing clinical cancer patient samples has not been achieved. Herein, we developed a novel LD-targetable and viscosity-sensitive fluorescent probe DPTP , based on diphenylamine-thiophene structure with multiple rotatable single bonds. DPTP displays an excellent selectivity and sensitivity toward viscosity changes in the range of 0.89–945 cP. Meanwhile, DPTP has excellent LD-targetable ability, and can monitor the increased viscosity level in the ferroptosis, inflammation, and heavy metal-induced cell injury models, respectively. Furthermore, facilitated with DPTP , we have successfully revealed a rise of LD viscosity in ambient PM 2.5 exposure-induced lung injury, and non-alcoholic fatty liver (NAFL) models. Significantly, the visualization of LD viscosity has also been achieved in tumor tissues containing surgical specimens of cancer patients for the first time, making DPTP a promising tool for cancer diagnosis and imaging-guided surgery.