Ratiometric fluorescence biosensor for imaging of protein phosphorylation levels in atherosclerosis mice

Atherosclerosis (AS) is the main cause of coronary heart disease, cerebral infarction and peripheral vascular disease, which is an important disease threatening human health. Abnormal levels of protein phosphorylation are closely related to the occurrence and development of diseases. Herein, the ratiometric fluorescence nanosensor (PCN/W- B@BSA) was prepared by using metal-organic frameworks (PCN-224) and fluorescent nanocluster wool-balls, which was applied for ratiometric fluorescence imaging of protein phosphorylation level in the AS mice model. Specific recognition of phosphorylation sites was achieved via specific interaction between active center Zr(IV) and phosphate. Using the two-photon property of porphyrin, the background is significantly reduced, and the sensitivity of imaging analysis is improved by combining with ratio imaging. Bovine serum albumin (BSA) was used to modify the surface of the nanosensor to reduce the non-specific adsorption and improve the biocompatibility of the nanosensor. Finally, the fluorescence nanosensor was successfully apply to fluorescence imaging of protein phosphorylation level in AS mice model, and the results showed that the protein phosphorylation level in the AS mice model was lower than that of the normal mice. The present study provides suitable fluorescence tool for further revealing phosphorylation related signaling pathways and disease mechanisms.