DNAzyme modified NaYF4: Yb, Tm, Gd for near-infrared fluorescence detection of uranyl

A novel near-infrared induced upconversion sensor for the detection of uranyl ions was successfully constructed using β -NaYF4: Yb, Tm, Gd upconversion nanoparticles (UCNPs) and specific DNAzyme. Characterization of the UCNPs@DNAzyme was conducted using XRD, TEM, FT-IR and fluorescence testing, and it was shown that the β -NaYF4: Yb, Tm, Gd nanoparticles were successfully prepared (∼27 nm). Upon 980 nm excitation, the UCNPs@DNAzyme emitted green light at λ =475 nm. Furthermore, Förster resonance energy transfer was observed between the UCNPs@DNAzyme (doner) and uranyl (acceptor) present on the substrate chain. This resulted in fluorescence quenching, which was used to quantify the concentration of uranyl. The developed method was found to be highly selective and sensitive, with a detection limit as low as 43 nM. This method also demonstrated excellent specificity and sensitivity for the determination of uranyl in water samples, indicating its potential application in near-infrared fluorescence detection and imaging of uranyl in vivo .