Upconversion of NaYF4: Yb, Er Nanoparticles Co-doped with Zr 4+ for Magnetic Phase Transition and Biomedical Imaging Applications

Tracking of cancer cells and cytotoxicity of normal tissue are the leading problem in cancer treatment. The magnetic and fluorescent multifunctional particles evolve as an emerging alternative for future target recognition. The ferromagnetic materials potentially treat the defects in the gene. Hence, ferromagnetic materials are the best for the treatment of cancer using gene therapy. Here, β-NaYF4: Yb, Er compounds doped with 10%, 20% and 30% Zirconium (Zr) are prepared through hydrothermal technique. Citrate itself is a highly biocompatible surface ligand that labels the imaging probe. The X-ray diffraction analysis is evident for transforming hexagonal to cubic phase via Zr doping in NaYF4: Yb, Er compounds. The electron microscopic images identify the hexagonal plates. This compound can emit visible light in response to infrared (IR) light irradiation. Especially β-NaYF4: Yb, Er, and 10% of Zr, Yb, Er tridoped NaYF4 compounds show enhanced red emission exploited in bioimaging applications. Insignificantly, 30% of Zr, Yb, Er tridoped NaYF4 concentration exhibit hexagonal and dominating cubic (α) phase, could decrease red emissions intensity and magnetisation value. This Zr material reveals peculiar magnetic properties, especially ferromagnetism at a lower magnetic field and produces paramagnetism at a higher magnetic field. Here, 10–20% Zr, Yb, Er tridoped NaYF4 concentrations exhibit better magnetic properties. The resultant compound is viable for the VERO cells.