A facile synthesis of water-soluble BaYF5:Ln3 + NCs with excellent luminescent properties as promising contrast agent for dual-modal bioimaging

• Monodisperse and uniform BaYF5:Ln3 + NCs with two different shapes are obtained.
• The synthetic process is facile, convenient and environmental-friendly.
• A thin layer of SiO2 is coated on BaYF5:Ln3 + NCs.
• The water-soluble NCs have good luminescent properties and low cytotoxicity.

Monodisperse, water-dispersible lanthanide (Ln3 +)-doped BaYF5 nanocrystals (NCs) are synthesized through a fast, facile and environmentally–friendly microwave-assisted modified polyol process with polyethyleneimine as the surfactant. The TEM images illustrate the sphere-like and flower-like morphologies of the obtained NCs. Intense multicolor down conversion (DC) luminescence is also achieved in Ce3 +/Ln3 + (Ln = Tb, Dy) doped BaYF5 NCs. Then, upon excitation at 980 nm, upconversion (UC) luminescent properties of BaYF5:Yb3 +/Ln3 + (Ln = Er, Tm, Ho) NCs and energy transfer between Yb3 + and Ln3 + are systematically surveyed. Furthermore, a layer of SiO2 is coated on the surface of the NCs and the methyl thiazolyl tetrazolium (MTT) assays are performed to test the cytotoxicity of BaYF5:Ln3 + NCs. Due to the X-ray absorption property of Ba element, a proof-of-concept CT imaging with BaYF5:Ln3 + NCs is conducted. These results indicate that the obtained NCs have great potential as optical/CT bioprobe.

Monodisperse, water-dispersible BaYF5:Ln3 + nanospheres and nanoflowers were synthesized via microwave-assisted modified polyol process. The obtained NCs with excellent up-down luminescent property and X-ray absorption property have great potential as optical/CT bioprobe.Figure optionsDownload as PowerPoint slide