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

Abstract

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.

A single-cell based mass cytometry study on heterogeneous interactions between upconversion nanoparticles and human immune cells

“…Therefore, we found that phagocytic cells (such as monocytes and dendritic cells) had higher affinity to the UCNPs than the other nonphagocytic cells. In addition, PG clustering algorithms were used to identify sub-cell types of monocytes and dendritic cells, which is sub-divided into 3 clusters (PG#1, 4, 18) and 4 clusters (PG#2, 3,19,27), respectively. Our study demonstrated a new technical framework to understand the heterogeneous interactions of conventional nanomaterials with complex human immune cells, which will be helpful for the safe use of nanomaterials in biomedical applications.…”

“…Inversely, lanthanide-doped upconversion nanoparticles (UCNPs) convert low-energy light into higherenergy light by multiphoton absorption, which is advantageous to increasing the penetration depth and reducing autofluorescence and photobleaching under a nearinfrared (NIR) laser. 17,18 The unique optical properties of UCNPs make them the best candidates for effective biomedical applications, such as MRI, 19 chemical sensing, 4 drug delivery, 20 color display technologies, 21 solar cells, 22 and photoswitching. 23 With the increasing application of UCNPs, there are increasing concerns about the possible toxicity of UCNPs to human health.…”

NIR-Triggered Release of Nitric Oxide by Upconversion-Based Nanoplatforms to Enhance Osteogenic Differentiation of Mesenchymal Stem Cells for Osteoporosis Therapy

“…The core of NaGdF 4 :Yb/Er was synthesized by a thermal decomposition method [ 35 ]. Briefly, a 50-ml 3-necked flask containing 15 ml of OA and 30 ml of ODE was added with 0.25 mmol of Yb(CH 3 CO 2 ) 3 , 0.745 mmol of Gd(CH 3 CO 2 ) 3 , and 0.005 mmol of Er(CH 3 CO 2 ) 3 , heated at 160 °C to make a clear solution, and then cooled to room temperature.…”

Bioimaging with Upconversion Nanoparticles

“…[86] Gadolinium particles can also be used in trimodal CT/ MRI/UCL imaging. [228] One potential drawback in MRI-UCNP bimodal imaging could be the extent of nanoparticle delivery efficiency, as most in vitro UCNP-MRI experiments showed limits of UCNP detection when gadolinium concentrations were in the single μM range. [225,229] Additionally, research into erbium-based UCNPs showed a reduction in UCL intensity with gadolinium instead of yttrium particle cores, potentially hindering UCL/MR multimodal imaging.…”