Carbon-Dot and Quantum-Dot-Coated Dual-Emission Core–Satellite Silica Nanoparticles for Ratiometric Intracellular Cu2+ Imaging

Copper (Cu2+) is physiologically essential, but excessive Cu2+ may cause potential risk to plants and animals due to the bioaccumulative properties. Hence, sensitive recognition is crucial to avoid overintake of Cu2+, and visual recognition is more favored for practical application. In this work, a dual-emission ratiometric fluorescent nanoprobe was developed possessing the required intensity ratio, which can facilitate the sensitive identification of Cu2+ by the naked eye. The probe hybridizes two fluorescence nanodots (quantum dots (QDs) and carbon dots (CDs)). Although both of them can be viable fluorescence probes for metal ion detection, rarely research has coupled this two different kinds of fluorescence material in one nanosensor to fabricate a selectively ratiometric fluorescence probe for intracellular imaging. The red emitting CdTe/CdS QDs were capped around the silica microsphere to serve as the response signal label, and the blue-emitting CDs, which is insensitive to the analyte, were covalent...