Design and synthesis of a vanadate-based ratiometric fluorescent probe for sequential recognition of Cu ions and biothiols.

A novel YVO4:Eu3+@CDs core-shell nanomaterial with two main emission peaks at 405 and 617 nm was synthesized through a simple mixing method, in which the carbon quantum dots (CDs) self-assembled with the YVO4:Eu3+ nanoparticle, due to the high affinity of oxygen-containing groups such as -COOH or -OH of CDs to the metal ions on the surface of YVO4:Eu3+. The red fluorescence of YVO4:Eu3+@CDs located at 617 nm can be quenched by Cu2+ ions efficiently, while the blue emission remains invariable; based on this, we construct a ratio fluorescent probe YVO4:Eu3+@CDs for Cu2+ ion detection, in which the blue emission of CDs is selected as the reference signal, and the red emission of YVO4:Eu3+ acts as an output signal. Furthermore, the addition of biothiol recovers the quenched red fluorescence quickly, which can be completed in 18 minutes.

Fluorescence Turn-On Detection of Ascorbic Acid Using a Self-Assembled Lanthanide Polymer Nanoparticle.

Ascorbic acid (AA), or vitamin C, is an important reactive biological molecule in vivo, and an abnormal level of AA is associated with many diseases. Therefore, the rapid, sensitive, and selective detection of AA levels is of significance in cases of medical assay and diagnosis. Compared with other nanoparticles, lanthanide coordination polymer nanoparticles (Ln-CPs) have been demonstrated as the excellent biomolecule sensing platforms due to their unique optical properties and intrinsic porosities.