Development of a selective “on-off-on” nano-sensor based on lanthanide encapsulated carbon dots

- A Hybrid inorganic-organic chemical sensor has been designed.
- A stepwise assembly method has been used to generate responses.
- Three targets could be determined by this functional sensor.

The example of a lanthanide based hybrid nanoprobe has been developed through functionalization of carbon dots with the organic pendant arms (ethylenediaminetetraaceticdianhydride). This assay has been designed for the highly specific recognition of an anthracis biomarker (2,6-pyridinedicarboxylic acid, DPA) in pure aqueous medium and the improved red emissions increase with the addition of DPA. In the next stage, this nanosystem demonstrates high selectivity for the determination of copper ions in terms of the switch-off effect. Furthermore, the presence of thiols such as glutathione (GSH) has induced large enhancements of the red luminescence. The corresponding detection limits are determined to be 137 nM for DPA, 80 nM for Cu(II) and 50 nM for GSH respectively. The employments of organic solvents, separation treatments and advanced instrumentations have been ruled out during the detection processes. The luminescence changes can be realized with the bare eye observation under the irradiation of a portable UV lamp. The results reported here may open the new way for designing multiple tailor-made sensing systems by finely tuning the features of both organic moieties and carbon nanostructures.