Hydrophobic-carbon-dot-based dual-emission micelle for ratiometric fluorescence biosensing and imaging of Cu2+ in liver cells

Copper is closely related to liver damage, therefore, it is essential to develop a simple and sensitive strategy to detect copper ions (Cu2+) in liver cells. A hydrophobic carbon dots (HCDs)-based dual-emission fluorescent probe for Cu2+ was prepared by encapsulating HCDs in micelles formed by self-assembly of amphiphilic polymer DSPE-PEG and tetrakis (4-carboxyphenyl) porphyrin (TCPP)-modified DSPE-PEG. The obtained probe showed characteristic fluorescence emissions of HCDs and TCPP with large emission shift of 170 nm with single-wavelength excitation. In the presence of Cu2+, the fluorescence of TCPP was quenched and that of HCDs remained unchanged, displaying ratiometric fluorescence response to Cu2+. The developed probe exhibited high sensitivity (detection limit down to 36 nM) and selectivity to Cu2+ over other substances, and the probe was used to image the changes of Cu2+ level in liver cells successfully.