Cardiovascular diseases (CVDs) pose a serious threat to human health, with atherosclerosis being a leading cause of heart disease and stroke. Elevated cysteine (Cys) levels have been closely linked to an increased risk of cardiovascular diseases, underscoring its significance in cardiovascular health. However, current detection methods for cysteine in serum and atherosclerotic plaques present challenges in sensitivity, specificity, dynamic monitoring, and invasiveness. The development of more sensitive, specific, and noninvasive assays is needed to enable accurate monitoring of cysteine levels. This study introduces the development and characterization of Cys-NPs, a sensitive and selective tool for imaging cysteine in foam cells and atherosclerotic mice. Encapsulation of the HD-probe using DSPE-PEG to obtain Cys-NPs effectively reduced interference from glutathione (GSH), leading to successful preparation and validation of Cys-NPs's nanoscale structure. At the same time, Cys-NPs was able to use the differences in Hcy and Cys concentrations in vivo to better assess Cys levels in vivo. In vitro and in vivo studies demonstrated Cys-NPs's effective imaging of cysteine in foam cells and atherosclerotic mice, highlighting its potential for noninvasive assessment of cysteine levels in ischemic heart disease research and clinical practice.
Keywords: cysteine; fluorescence imaging; ischemic cardiovascular disease; photoacoustic imaging; serum detection.