Label-free iodide detection using functionalized carbon nanodots as fluorescent probes

A label-free fluorescent nanoprobe for iodide ion (I − ) detection was developed based on the direct fluorescence quenching of spermine-functionalized carbon dots (SC-dots), whether in complex biological fluids or living cells. The positively charged SC-dots were fabricated via one-step microwave synthesis and exhibited excellent optical properties. Due to the strong quenching ability of I − , SC-dots were utilized for I − detection with high sensitivity and excellent selectivity, which offered a relatively low detection limit of 0.18 μM. This strategy was also successfully applied for I − detections in human serum and HeLa cells. The detection process is facile, highly sensitive and selective, providing a new insight into the potential applications of SC-dots for anion nanoprobe designs in clinical diagnosis and other biologically related areas. Graphical abstract