EuPO₄·H₂O nanorods/nanoparticles with a rhabdophane-type hexagonal form have been successfully synthesized using microwave assisted co-precipitation. The effects of chemical composition and pH on the size, shape, morphology and luminescence properties have been investigated by powder X-ray diffraction, Field Emission Scanning Electron Microscopy (FESEM), and photoluminescence spectroscopy. The mean size of the nanorods is about 15–30 nm in diameter and 200–400 nm in length and the size of nanoparticles is 10–20 nm. A powdered sample of these EuPO₄·H₂O nanorods/nanoparticles emitted yellow-green light with narrow bands at 594, 619, 652, and 697 nm under UV-vis excitation. The surface effects of the built core–shell structure on the fluorescent properties, and the compatibility of the EuPO₄·H₂O nanomaterials with a biological system, have been studied to develop a new fluorescent label for biomedical imaging. The primary test results in using a EuPO₄·H₂O–Immunoglobulin G conjugate for recognizing the measles virus in a vaccine is presented.

In this paper, the luminescent complex Eu(3-thenoyltrifluoroacetonate)₃ was integrated with Fe₃O₄ and gold (Au) nanoparticles to form a multifunctional nanocomposite, Fe₃O₄/Au/Eu(TTA)₃ (FOASET NC), for dual magnetic-photothermal therapy and biomedical imaging. Upon functionalization with amine-NH₂, the FOASET NC exhibits a small size of 60–70 nm and strong, sharp emission at λ_max = 614 nm, enhanced by surface plasmon resonance (SPR) of Au nanoparticles that provided an effective label for HT29 colorectal cancer cells by fluorescence microscopy imaging. In addition, a hyperthermia temperature (42–46 °C) was completely achieved by using these FOASET NCs in an aqueous solution with three heating modes for (i) Magnetic therapy (MT), (ii) Photothermal therapy (PT), and (iii) Dual magnetic-photothermal therapy (MPT). The heating efficiency was improved in the dual magnetic-photothermal heating mode.

NaYF ₄ :Yb ³⁺ /(Er ³⁺ ,Tm ³⁺ ) UCNPs were synthesized via a hydrothermal method and sequentially functionalized with silica shell, amine groups, thiocyanate (SCN), and immunoglobulin G (IgG) to enhance their biocompatibility and targeting capabilities.

Rare-earth nanomaterials are being widely applied in medicine as cytotoxicity agents, in radiation and photodynamic therapy, as drug carriers, and in biosensing and bioimaging technology. Terbium (Tb), a rare-earth element belonging to the lanthanides, has a long luminescent lifetime, large stock displacement, narrow spectral width, and biofriendly probes. In cancer therapy, cancer stem cell (CSC)-targeted treatment is receiving considerable attention due to these cells’ harmful characteristics. However, CSCs remain barely understood. Therefore, to effectively label and inhibit the growth of CSCs, we produced a nanocomplex in which TbPO₄·H₂O nanorods were double conjugated with CD133 and PD-L1 monoclonal antibodies. The Tb³⁺ nanomaterials were created in the presence of a soft template (polyethylene glycol 2000). The obtained nanomaterial TbPO₄·H₂O was hexagonal crystal and nanorod in shape, 40–80 nm in diameter, and 300–800 nm in length. The nanorods were further surfaced through tetraethyl orthosilicate hydrolysis and functionalized with amino silane. Finally, the glutaraldehyde-activated Tb³⁺ nanorods were conjugated with CD133 monoclonal antibody and PD-L1 monoclonal antibody on the surface to obtain the nanocomplex TbPO₄·H₂O@silica-NH₂+mAb^CD133+mAb^PD-L1 (TMC). The formed nanocomplex was able to efficiently and specifically label NTERA-2 cells, a highly expressed CD133 and PD-L1 CSC cell line. The conjugate also demonstrated promising anti-CSC activity by significant inhibition (58.50%) of the growth of 3D tumor spheres of NTERA-2 cells (p < 0.05).

This study presents the synthesis of NaYF₄: Er³⁺/Yb³⁺ upconversion luminescent nanomaterials using a wet chemistry method. The role of oleic acid in influencing the size, shape, and luminescent properties of the materials was also investigated. The results showed that, at a suitable oleic acid concentration of 10⁻³ M, the obtained nanoparticles exhibited a nearly spherical morphology with diameters ranging from 150 to 250 nm and predominantly display a hexagonal (β-NaYF₄) crystalline phase. Photoluminescence measurements under 980 nm laser excitation reveal that these nanoparticles emit strong, stable luminescence with narrow emission bands characteristic of Er³⁺ transitions. Subsequently, the nanoparticles were coated with a silica shell, functionalized with amine groups, and conjugated with IgG antibodies via glutaraldehyde (GA) to form the bio-nano complex β-NaYF₄: Er³⁺/Yb³⁺@SNGA-IgG. In vitro experiments using fluorescence microscopy demonstrated that the complex effectively labels HeLa cervical cancer cells. With its robust upconversion luminescence and excellent biocompatibility, the developed nanocomplex shows promising potential for rapid pathogen detection and other biomedical applications.