Upconversion, MRI imaging and optical trapping studies of silver nanoparticle decorated multifunctional NaGdF4:Yb,Er nanocomposite.

The multifunctional upconversion nanoparticles (UCNPs) are fascinating tool for biological applications. In the present work, photon upconverting NaGdF4:Yb,Er and Ag nanoparticles decorated NaGdF4:Yb,Er (NaGdF4:Yb,Er@Ag) nanoparticles were prepared using a simple polyol process. Rietveld refinement was performed for detailed crystal structural and phase fraction analysis. The morphology of the NaGdF4:Yb,Er@Ag was examined using high-resolution transmission electron microscope, which reveals silver nanoparticles of 8 nm in size were decorated over spherical shaped NaGdF4:Yb,Er nanoparticles with a mean particle size of 90 nm. The chemical compositions were confirmed by EDAX and inductively coupled plasma-optical emission spectrometry analyses. The upconversion luminescence (UCL) of NaGdF4:Yb,Er at 980 nm excitation showed an intense red emission. After incorporating the silver nanoparticles, the UCL intensity decreased due to weak scattering and surface plasmon resonance effect. The VSM magnetic measurement indicates both the UCNPs possess paramagnetic behaviour. The NaGdF4:Yb,Er@Ag showed computed tomography imaging. Magnetic resonance imaging study exhibited better T1 weighted relaxivity in the NaGdF4:Yb,Er than the commercial Gd-DOTA. For the first time, the optical trapping was successfully demonstrated for the upconversion NaGdF4:Yb,Er nanoparticle at near-infrared 980 nm light using an optical tweezer setup. The optically trapped UCNP possessing paramagnetic property exhibited a good optical trapping stiffness. The UCL of trapped single UCNP is recorded to explore the effect of the silver nanoparticles. The multifunctional properties for the NaGdF4:Yb,Er@Ag nanoparticle are demonstrated.

Fabrication of Multifunctional Drug Loaded Magnetic Phase Supported Calcium Phosphate Nanoparticle for Local Hyperthermia Combined Drug Delivery and Antibacterial Activity.

Magnetic calcium phosphate nanoparticles are biocompatible and have attracted much attention as biomaterials for bone tissue engineering and theranostic applications. In this study, we report the fabrication of a biocompatible magnetic nickel ferrite supported fluorapatite nanoparticle as a bone substitute material with hyperthermia potential using a facile wet precipitation approach. The composition and magnetic properties of the sample were analyzed using X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM). The presence of both magnetic (NiFe2O4 and γ-Fe2O3) and fluorapatite phases was identified, and the sample exhibited ferromagnetic behavior with saturation magnetization and coercivity of 3.08 emu/g and 109 Oe, respectively. The fabricated sample achieved the hyperthermia temperature of ∼43 °C under tumor mimic conditions (neglecting Brownian relaxation) in 2.67 min, and the specific loss power (SLP) was estimated to be 898 W/g(Ni+Fe) which is sufficient to prompt irreversible cell apoptosis. Biocompatibility of the synthesized nanoparticle was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium (MTT) assay with fibroblast NIH 3T3 and L929 cells. An in vitro drug release experiment was conducted at pH 5 (tumor mimic) and 7.4 (physiological), which revealed a release of 49.8% in the former and 11.6% in the latter pH for 11 days. The prepared sample showed antibacterial activity against S. aureus.

Nanocurcumin-Loaded UCNPs for Cancer Theranostics: Physicochemical Properties, In Vitro Toxicity, and In Vivo Imaging Studies.

Formulation of promising anticancer herbal drug curcumin as a nanoscale-sized curcumin (nanocurcumin) improved its delivery to cells and organisms both in vitro and in vivo. We report on coupling nanocurcumin with upconversion nanoparticles (UCNPs) using Poly (lactic-co-glycolic Acid) (PLGA) to endow visualisation in the near-infrared transparency window. Nanocurcumin was prepared by solvent-antisolvent method. NaYF4:Yb,Er (UCNP1) and NaYF4:Yb,Tm (UCNP2) nanoparticles were synthesised by reverse microemulsion method and then functionalized it with PLGA to form UCNP-PLGA nanocarrier followed up by loading with the solvent-antisolvent process synthesized herbal nanocurcumin. The UCNP samples were extensively characterised with XRD, Raman, FTIR, DSC, TGA, UV-VIS-NIR spectrophotometer, Upconversion spectrofluorometer, HRSEM, EDAX and Zeta Potential analyses. UCNP1-PLGA-nanocurcumin exhibited emission at 520, 540, 660 nm and UCNP2-PLGA-nanocurmin showed emission at 480 and 800 nm spectral bands. UCNP-PLGA-nanocurcumin incubated with rat glioblastoma cells demonstrated moderate cytotoxicity, 60-80% cell viability at 0.12-0.02 mg/mL marginally suitable for therapeutic applications. The cytotoxicity of UCNPs evaluated in tumour spheroids models confirmed UCNP-PLGA-nanocurcumin therapeutic potential. As-synthesised curcumin-loaded nanocomplexes were administered in tumour-bearing laboratory animals (Lewis lung cancer model) and showed adequate contrast to enable in vivo and ex vivo study of UCNP-PLGA-nanocurcumin bio distribution in organs, with dominant distribution in the liver and lungs. Our studies demonstrate promise of nanocurcumin-loaded upconversion nanoparticles for theranostics applications.