In this report, we describe the X-ray luminescent properties of two lanthanide-based nanoscale metal−frameworks (nMOFs) and their potential as novel platforms for optical molecular imaging techniques such as X-ray excited radioluminescence (RL) imaging. Upon X-ray irradiation, the nMOFs display sharp tunable emission peaks that span the visible to nearinfrared spectral region (∼400−700 nm) based on the identity of the metal (Eu, Tb, or Eu/Tb). Surface modification of the nMOFs with polyethylene glycol (PEG) resulted in nanoparticles with enhanced aqueous stability that demonstrated both cyto-and hemo-compatibility important prerequisites for biological applications. Importantly, this is the first report to document and investigate the radioluminescent properties of lanthanide nMOFs. Taken together, the observed radioluminescent properties and low in vitro toxicity demonstrated by the nMOFs render them promising candidates for in vivo translation.
High-density inorganic nanoparticles have shown promise in medical applications that utilize radiation including X-ray imaging and as radiation dose enhancers for radiotherapy. We have developed an aqueous synthetic method to produce small (~ 2 nm) iridium nanoparticles (IrNPs) by reduction of iridium(III) chloride using a borohydride reducing agent. Unlike other solution-based synthesis methods, uniform and monodispersed IrNPs are produced without the use of surfactants or other solubilizing ligands. These nanoparticles are highly crystalline as observed by X-ray diffraction and high-resolution transmission electron microscopy (TEM). In vitro metabolic toxicity assays using hepatocyte and macrophage cells demonstrate that both IrNPs and iridium(III) chloride are well tolerated at concentrations of up to 10 μM iridium. Furthermore, the IrNPs were assessed in a hemolytic assay and found to have no significant impact on red blood cells when exposed to concentrations up to 100 μM. Overall, these results support the potential for the in vivo application of this nanomaterial.Electronic supplementary materialThe online version of this article (10.1186/s11671-018-2621-3) contains supplementary material, which is available to authorized users.
The development of radiation responsive materials, such as nanoscintillators, enables a variety of exciting new theranostic applications. In particular, the ability of nanophosphors to serve as molecular imaging agents in...
Naturally-derived polysaccharides, such as alginate and chitosan, can be assembled to form nanocarriers for the delivery of therapeutic agents. Here we exploit the electrostatic complexation of alginate/chitosan in a water-in-oil (w/o) emulsion process to produce doxorubicin (DOX)-loaded nanoparticles (~80 nm) with exceptional spherical morphology and uniformity. This robust synthetic route utilizes an aqueous phase dispersed in a cyclohexane/dodecylamine organic phase and is capable of encapsulating DOX in the nanoparticle solution. The uptake and efficacy of this novel formulation was evaluated in a murine breast cancer cell line, 4T1, with comparable 72 h IC50 values of the nanoparticle solution (0.15 μg/mL) and free DOX (0.13 μg/mL). Overall, the favorable performance, physiochemical properties, and their facile production support these nanocarriers as promising platform for the delivery of aqueous soluble drugs.
Lanthanide-doped nanocrystals have
been examined extensively as
contrast agents for various optical molecular imaging techniques.
One of the greatest strengths of these nanomaterials is their
ability to enable novel imaging modalities, such as X-ray excited
radioluminescence imaging, which leverages the exceptional tissue
depth penetration of X-rays and reduced tissue autofluorescence. Here,
we report a uniquely engineered NaGdF4/Tb@CaF2 nanoscintillator with substantial lattice mismatch through integration
of coprecipitation and thermal decomposition synthetic routes. We
observed greatly enhanced radioluminescence by the NaGdF4/15%Tb@CaF2 core/shell nanocrystals, which results from
the minimized surface quenching and localized structure transformation.
Polyethylene glycol coated NaGdF4/15%Tb@CaF2 nanocrystals demonstrated robust aqueous colloidal stability and
were well tolerated by a panel of cell lines. The core/shell NaGdF4/15%Tb@CaF2 nanophosphors were subsequently decorated
with targeting folate ligands and investigated as an X-ray luminescence
imaging probe in vitro. Overall, the results suggest that these optimized
radioluminescent nanophosphors have the potential to enable X-ray
excited optical emission for biological imaging and serve as energy
mediators in theranostic applications.
Herein, we report an aerobic synthesis method to produce bismuth nanoparticles (Bi NPs) with average diameters in the range 40-80 nm using commercially available bismuth triiodide (BiI 3 ) as starting material; the method uses only readily available chemicals and conventional laboratory equipment. Furthermore, size data from replicates of the synthesis under standard reaction conditions indicate that this method is highly reproducible in achieving Bi NP populations with low standard deviations in the mean diameters. We also investigated the mechanism of the reaction, which we determined results from the reduction of a soluble alkylammonium iodobismuthate precursor species formed in situ. Under appropriate concentration conditions of iodobismuthate anion, we demonstrate that burst nucleation of Bi NPs results from reduction of Bi 3+ by the coordinated, redox noninnocent iodide ligands when a threshold temperature is exceeded. Finally, we demonstrate phase transfer and silica coating of the Bi NPs, which results in stable aqueous colloids with retention of size, morphology, and colloidal stability. The resultant, high atomic number, hydrophilic Bi NPs prepared using this synthesis method have potential for application in emerging X-ray contrast and X-ray therapeutic applications.
Bismuth has gained attention in preclinical research because of its ability to attenuate X-rays and high biocompatibility, which make it an excellent element for use in a biomedical agent or in radiation shielding. Developments in the synthesis of elemental bismuth nano-and microparticles, their X-radiation interactions, and their biological interactions will be reviewed in this chapter. The chapter will pay special focus to emerging medical applications of elemental bismuth nano-and microparticles, including the possibility of targeted molecular X-ray imaging, photo-thermal and X-radiation dose enhancing therapies for cancer treatment, and the construction of flexible radiation shielding materials and X-ray opaque devices.
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