Probing Highly Luminescent Europium-Doped Lanthanum Orthophosphate Nanorods for Strategic Applications

Herein we have established a strategy for the synthesis of highly luminescent and biocompatible europium-doped lanthanum orthophosphate (La0.85PO4Eu0.153+) nanorods. The structure and morphogenesis of these nanorods have been probed by XRD, SEM, and TEM/HRTEM techniques. The XRD result confirms that the as-synthesized nanorods form in a monazite phase with a monoclinic crystal structure. Furthermore, the surface morphology shows that the synthesized nanorods have an average diameter of similar to 90 nm and length of similar to 2 mu m. The HRTEM images show clear lattice fringes that support the presence of better crystal quality and enhanced photoluminescence hypersensitive red emission at 610 nm (D-5(0)-F-7(2)) upon 394 nm wavelength excitation. Furthermore, time-resolved spectroscopy and an MTT assay of these luminescent nanorods demonstrate a photoluminescent decay time of milliseconds with nontoxic behavior. Hence, these obtained results suggest that the as-synthesized luminescent nanorods could be potentially used in invisible security ink and high-contrast bioimaging applications

Tunable luminescence from two dimensional BCNO nanophosphor for high-contrast cellular imaging

Rare-earth free and biocompatible two dimensional carbon based boron oxynitride (2D BCNO) nanophosphors were synthesized using facile auto-combustion of inexpensive compounds such as urea, boric acid and polyethylene glycol at ambient atmosphere and relatively low temperatures. The surface morphology and microstructure images indicate that the nanophosphor has 2D layered structures and analogous mixed hexagonal lattices of boron nitride (BN) and graphene (C). The nanophosphor exhibits a single, distinct and broad photoluminescence emission and this emission colour can be easily tuned from violet to deep red by varying the amount of boron/carbon content. The time-resolved and photoluminescence spectroscopic results indicate that B-O act as luminescence centers, which are responsible for the tunable luminescent properties while carbon impurities induce energy levels in the band gap of 2D BCNO nanophosphors. These tunable and biocompatible luminescent nanophosphors are used for in vitro high-contrast cellular imaging of HeLa cells derived from human cervical cancer cells as well as in vivo imaging in C57BL/6J mice. Hence, these novel multi-colour emitting nanophosphors provide a paradigm shift in rare-earth free biocompatible nanoprobes for next generation high-contrast in vitro and in vivo imaging applications

Bifunctional Luminomagnetic Rare-Earth Nanorods for High-Contrast Bioimaging Nanoprobes

Nanoparticles exhibiting both magnetic and luminescent properties are need of the hour for many biological applications. A single compound exhibiting this combination of properties is uncommon. Herein, we report a strategy to synthesize a bifunctional luminomagnetic Gd2-xEuxO3 (x = 0.05 to 0.5) nanorod, with a diameter of similar to 20 nm and length in similar to 0.6 mu m, using hydrothermal method. Gd2O3:Eu3+ nanorods have been characterized by studying its structural, optical and magnetic properties. The advantage offered by photoluminescent imaging with Gd2O3:Eu3+ nanorods is that this ultrafine nanorod material exhibits hypersensitive intense red emission (610 nm) with good brightness (quantum yield more than 90%), which is an essential parameter for high-contrast bioimaging, especially for overcoming auto fluorescent background. The utility of luminomagnetic nanorods for biological applications in high-contrast cell imaging capability and cell toxicity to image two human breast cancer cell lines T47D and MDA-MB-231 are also evaluated. Additionally, to understand the significance of shape of the nanostructure, the photoluminescence and paramagnetic characteristic of Gd2O3:Eu3+ nanorods were compared with the spherical nanoparticles of Gd2O3:Eu3+

Graphene Quantum Dots Derived from Carbon Fibers

Graphene quantum dots (GQDs), which are edge-bound nanometer-size graphene pieces, have fascinating optical and electronic properties. These have been synthesized either by nanolithography or from starting materials such as graphene oxide (GO) by the chemical breakdown of their extended planar structure, both of which are multistep tedious processes. Here, we report that during the acid treatment and chemical exfoliation of traditional pitch-based carbon fibers, that are both cheap and commercially available, the stacked graphitic submicrometer domains of the fibers are easily broken down, leading to the creation of GQDs with different size distribution in scalable amounts. The as-produced GQDs, in the size range of 1-4 nm, show two-dimensional morphology, most of which present zigzag edge structure, and are 1-3 atomic layers thick. The photoluminescence of the GQDs can be tailored through varying the size of the GQDs by changing process parameters. Due to the luminescence stability, nanosecond lifetime, biocompatibility, low toxicity, and high water solubility, these GQDs are demonstrated to be excellent probes for high contrast bioimaging and biosensing applications

Graphene Quantum Dots Derived from Carbon Fibers

Graphene quantum dots (GQDs), which are edge-bound nanometer-size graphene pieces, have fascinating optical and electronic properties. These have been synthesized either by nanolithography or from starting materials such as graphene oxide (GO) by the chemical breakdown of their extended planar structure, both of which are multistep tedious processes. Here, we report that during the acid treatment and chemical exfoliation of traditional pitch-based carbon fibers, that are both cheap and commercially available, the stacked graphitic submicrometer domains of the fibers are easily broken down, leading to the creation of GQDs with different size distribution in scalable amounts. The as-produced GQDs, in the size range of 1–4 nm, show two-dimensional morphology, most of which present zigzag edge structure, and are 1–3 atomic layers thick. The photoluminescence of the GQDs can be tailored through varying the size of the GQDs by changing process parameters. Due to the luminescence stability, nanosecond lifetime, biocompatibility, low toxicity, and high water solubility, these GQDs are demonstrated to be excellent probes for high contrast bioimaging and biosensing applications