nanocrystals (0 ≤ x ≤ 1): growth, size control and shell formation on β-NaCeF4:Tb core particles

is an interesting shell material for β-NaREF₄ particles of the lighter lanthanides (RE = Ce, Pr, Nd), as variation of its strontium content x allows to vary its lattice parameters and match those of the core material.

Detection of lymph node metastasis with near-infrared upconversion luminescent nanoprobes

The detection of lymph node metastasis is of great importance for therapy planning and prognosis of cancers, but remains challenging in the clinic. In the current study, we report a tumor-specific imaging probe constructed with NaGdF4:Yb,Tm,Ca@NaLuF4 core@shell upconversion nanoparticles showing distinctive near infrared emission. The following studies revealed that the characteristic Tm dopant emission at 804 nm showed a penetration depth up to 7.7 mm through multi-layered mice skin tissues, substantially greater than emissions at 655 nm and 541 nm typically from the widely used Er dopant, which is apparently favorable for sensitive tumor diagnosis. The cell binding assay further revealed that the anti-HER2 antibodies covalently attached on the particle surface endowed the nanoprobe with excellent binding specificity in targeting HER2-positive cancer cells in vitro, which further enabled the detection of lymph node metastasis of breast cancer in vivo in mice. In addition, the pharmacokinetics of the resulting nanoprobes were intensively studied through both upconversion luminescence imaging and SPECT imaging for comparing with that of the mother particles. The results obtained through both approaches were well consistent and revealed that the surface conjugation of antibodies largely altered the pharmacokinetic behaviors and substantially prolonged the blood half-life of the underlying nanoparticles, which was never reported before.

Morphology control and enhancement of 1.5 μm emission in Ca2+/Ce3+ codoped NaGdF4:Yb3+, Er3+ submicrorods

Irregular NaGdF₄:Yb/Er submicrocrystals converted into uniform submicrorods and the ∼1530 nm emission was enhanced via Ca²⁺/Ce³⁺ codoping.