Covalent bridging of surface functionalized Fe₃O₄ and YPO₄:Eu nanostructures for simultaneous imaging and therapy

Abstract

Magnetic luminescent hybrid nanostructures (MLHN) have received a great deal of attention due to their potential biomedical applications such as thermal therapy, magnetic resonance imaging, drug delivery and intracellular imaging. We report the development of bifunctional Fe3O4 decorated YPO4:Eu hybrid nanostructures by covalent bridging of carboxyl PEGylated Fe3O4 and amine functionalized YPO4:Eu particles. The surface functionalization of individual nanoparticulates as well as their successful conjugation was evident from Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), zeta-potential and transmission electron microscopy (TEM) studies. X-ray diffraction (XRD) analysis reveals the formation of highly crystalline hybrid nanostructures. TEM micrographs clearly show the binding/anchoring of 10 nm Fe3O4 nanoparticles onto the surface of 100-150 nm rice grain shaped YPO4:Eu nanostructures. These MLHN show good colloidal stability, magnetic field responsivity and self-heating capacity under an external AC magnetic field. The induction heating studies confirmed localized heating of MLHN under an AC magnetic field with a high specific absorption rate. Photoluminescence spectroscopy and fluorescence microscopy results show optical imaging capability of MLHN. Furthermore, successful internalization of these MLHN in the cells and their cellular imaging ability are confirmed from confocal microscopy imaging. Specifically, the hybrid nanostructure provides an excellent platform to integrate luminescent and magnetic materials into one single entity that can be used as a potential tool for hyperthermia treatment of cancer and cellular imaging.

Correlative Cathodoluminescence Electron Microscopy: Immunolabeling Using Rare‐Earth Element Doped Nanoparticles

“…For protein targeting, YPO 4 :Tb 3+ nanoparticles were subjected to further surface functionalization. First, amine groups were introduced on the particle surface via silanization ((3‐Aminopropyl)triethoxysilane, APTES) [ 29 ] (yielding YPO 4 :Tb 3+ ‐APTES), followed by the coupling of folic acid (FA) using EDC/NHS chemistry [ 26 ] (yielding YPO 4 :Tb 3+ ‐FA) ( Figure a; Scheme S1, Supporting Information). The surface functionalization was confirmed via Fourier Transform Infrared spectroscopy (FTIR) and elemental analysis (carbon‐nitrogen‐hydrogen, CHN).…”

“…The FTIR spectrum of unfunctionalized nanoparticles shows an intense double‐peak around 1000 cm −1 , corresponding to phosphate groups (Figure 2b). [ 29 ] The spectrum also indicates the presence of adsorbed solvent molecules on the surface indicated by peaks corresponding to CH 2  (2950 cm −1 ) and OH bonds (3100–3400 cm −1 ). Due to the overlap of the phosphate peak with the SiO peak, no major alterations in the FTIR spectrum were detectable upon APTES modification.…”

“…First, as‐prepared YPO 4 nanoparticles (120 mg) were functionalized with APTES according to previous reports. [ 29 ] Particles were dispersed in ethanol (420 mL) and sonicated in the ultrasonication bath for 1 h. Then 15% ammonia aqueous solution (30 mL) was added to the mixture and sonicated for another 15 min. After that, APTES (1.2 mL, 5.18 mmol) was added dropwise to the reaction mixture under vigorous stirring and left to react for 1 h at room temperature.…”

Nanoparticle Functionalization and Its Potentials for Molecular Imaging

“…The amine groups linked to the YPO4: Eu NPs couple with carboxyl groups in the PEGylated iron oxide particles which make up the hybrid nanostructures. Barick et al proved that the magnetic field induced by alternating current can cause self‐heating of these hybrid particles at highly specific absorption rates which enables us to control the therapy while imaging 93. Just the SPIONs have a good heating capacity of about 500 W g −1 Fe in alternating magnetic field of particular conditions of frequency.…”

Synthesis, Characterization and Cytotoxicity of Novel Multifunctional Fe3O4@SiO2@GdVO4:Dy3+ Core-Shell Nanocomposite as a Drug Carrier

“…The previous investigation results indicated that nanosized GdVO 4 :Ln 3+ phosphors have a significant application in a high definition flat display panels and potential applications in biology [16,17,18,19]. Compared with Ln 3+ -activated YVO 4 , GdVO 4 :Ln 3+ exhibits highly efficient emitting phosphors, in which the energy transfers from the GdVO 4 host to the incorporated Ln 3+ ions through V 5+ –O 2− charge transfer (CT), yielding an efficient luminescence of Ln 3+ activators.…”