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https://www.readbyqxmd.com/read/28342376/label-free-silicon-nanodots-featured-ratiometric-fluorescent-aptasensor-for-lysosomal-imaging-and-ph-measurement
#1
Yanan Zhang, Shan Guo, Shibo Cheng, Xinghu Ji, Zhike He
The homeostasis of lysosomal pH is crucial in cell physiology. Developing small fluorescent nanosensors for lysosome imaging and ratiometric measurement of pH is highly demanded yet challenging. Herein, a pH-sensitive fluorescein tagged aptamer AS1411 has been utilized to covalently modify the label-free fluorescent silicon nanodots via a crosslinker for construction of a ratiometric pH biosensor. The established aptasensor exhibits the advantages of ultrasmall size, hypotoxicity, excellent pH reversibility and good photostability, which favors its application in an intracellular environment...
March 22, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28327599/metal-organic-framework-templated-synthesis-of-ultrasmall-catalyst-loaded-zno-znco2o4-hollow-spheres-for-enhanced-gas-sensing-properties
#2
Won-Tae Koo, Seon-Jin Choi, Ji-Soo Jang, Il-Doo Kim
To achieve the rational design of nanostructures for superior gas sensors, the ultrasmall nanoparticles (NPs) loaded on ternary metal oxide (TMO) hollow spheres (HS) were synthesized by using the polystyrene (PS) sphere template and bimetallic metal-organic framework (BM-MOFs) mold. The zinc and cobalt based zeolite imidazole frameworks (BM-ZIFs) encapsulating ultrasmall Pd NPs (2-3 nm) were assembled on PS spheres at room temperature. After calcination at 450 °C, these nanoscale Pd particles were effectively infiltrated on the surface of ZnO/ZnCo2O4 HSs...
March 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28327075/magnetic-nanobubbles-with-potential-for-targeted-drug-delivery-and-trimodal-imaging-in-breast-cancer-an-in-vitro-study
#3
Weixiang Song, Yindeng Luo, Yajing Zhao, Xinjie Liu, Jiannong Zhao, Jie Luo, Qunxia Zhang, Haitao Ran, Zhigang Wang, Dajing Guo
AIM: The aim of this study was to improve tumor-targeted therapy for breast cancer by designing magnetic nanobubbles with the potential for targeted drug delivery and multimodal imaging. MATERIALS & METHODS: Herceptin-decorated and ultrasmall superparamagnetic iron oxide (USPIO)/paclitaxel (PTX)-embedded nanobubbles (PTX-USPIO-HER-NBs) were manufactured by combining a modified double-emulsion evaporation process with carbodiimide technique. PTX-USPIO-HER-NBs were examined for characterization, specific cell-targeting ability and multimodal imaging...
March 13, 2017: Nanomedicine
https://www.readbyqxmd.com/read/28323636/ultrasmall-water-dispersible-tween80-modified-yb-er-nagd-wo-sub-4-sub-sub-2-sub-nanoparticles-with-record-upconversion-ratiometric-thermal-sensitivity-and-their-internalization-by-mesenchymal-stem-cells
#4
Concepcion Cascales, Carlos Paino, Eulalia Bazán, Carlos Zaldo
This work presents the synthesis by coprecipitation of diamond shaped Yb:Er:NaGd(WO<sub>4</sub>)<sub>2</sub> crystalline nanoparticles (NPs) with diagonal dimensions in the 5-7 nm × 10-12 nm range which have been modified with TWEEN80 for their dispersion in water, and their interaction with mesenchymal stem cells (MSCs) proposed as cellular NP vehicles. These NPs belong to a large family of tetragonal Yb:Er:NaT(XO<sub>4</sub>)<sub>2</sub> (T=Y, La, Gd, Lu; X= Mo, W) compounds with green (<sup>2</sup>H<sub>11/2</sub>+<sup>4</sup>S<sub>3/2</sub>→<sup>4</sup>I<sub>15/2</sub>) Er-related upconversion (UC) efficiency comparable to that of Yb:Er:β-NaYF<sub>4</sub> reference compound, but with a ratiometric thermal sensitivity (S) 2...
March 21, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28314103/computational-study-of-the-forces-driving-aggregation-of-ultrasmall-nanoparticles-in-biological-fluids
#5
Sergio A Hassan
Nanoparticle (NP) aggregation can lead to prolonged retention in tissues or embolism, among other adverse effects. Successful use in biomedicine thus requires the capability to make NPs with limited aggregative potential. Rational design is presently a challenge due to incomplete knowledge of their interactions in biofluids. Recently, ultrasmall gold NPs passivated with endogenous antioxidant glutathione have shown promise for use in vivo. Computer simulations are here conducted to identify the forces underlying aggregation (or lack thereof) of these NPs in a cell culture...
March 21, 2017: ACS Nano
https://www.readbyqxmd.com/read/28301748/single-molecule-arrays-for-protein-and-nucleic-acid-analysis
#6
Limor Cohen, David R Walt
The last few years have seen breakthroughs that will transform our ability to measure important analytes. Miniaturization of reaction volumes and confinement of analytes of interest into ultrasmall containers have greatly enhanced the sensitivity and throughput of many detection methods. Fabrication of microwell arrays and implementation of bead-based assays have been instrumental in the development of methods for measuring relevant biomolecules, with applications to both diagnostics and fundamental biological studies...
March 15, 2017: Annual Review of Analytical Chemistry
https://www.readbyqxmd.com/read/28295960/interactions-of-renal-clearable-gold-nanoparticles-with-tumor-microenvironments-vasculature-and-acidity-effects
#7
Mengxiao Yu, Chen Zhou, Li Liu, Shanrong Zhang, Shasha Sun, Julia D Hankins, Xiankai Sun, Jie Zheng
The success of nanomedicines in the clinic depends on our comprehensive understanding of nano-bio interactions in tumor microenvironments, which are characterized by dense leaky microvasculature and acidic extracellular pH (pHe ) values. Herein, we investigated the accumulation of ultrasmall renal-clearable gold NPs (AuNPs) with and without acidity targeting in xenograft mouse models of two prostate cancer types, PC-3 and LNCaP, with distinct microenvironments. Our results show that both sets of AuNPs could easily penetrate into the tumors but their uptake and retention were mainly dictated by the tumor microvasculature and the enhanced permeability and retention effect over the entire targeting process...
March 13, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28295888/regimes-of-biomolecular-ultrasmall-nanoparticle-interactions
#8
Luca Boselli, Ester Polo, Valentina Castagnola, Kenneth A Dawson
Ultrasmall nanoparticles (USNPs), usually defined as NPs with core in the size range 1-3 nm, are a class of nanomaterials which show unique physicochemical properties, often different from larger NPs of the same material. Moreover, there are also indications that USNPs might have distinct properties in their biological interactions. For example, recent in vivo experiments suggest that some USNPs escape the liver, spleen, and kidney, in contrast to larger NPs that are strongly accumulated in the liver. Here, we present a simple approach to study the biomolecular interactions at the USNPs bio-nanointerface, opening up the possibility to systematically link these observations to microscopic molecular principles...
March 15, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28291332/metal-substrate-mediated-plasmon-hybridization-in-a-nanoparticle-dimer-for-photoluminescence-line-width-shrinking-and-intensity-enhancement
#9
Guang-Can Li, Yong-Liang Zhang, Jing Jiang, Yu Luo, Dang Yuan Lei
Metal-film-coupled nanoparticles with subnanometer particle-film gaps possess an ultrasmall mode volume, responsible for a variety of intriguing phenomena in plasmonic nanophotonics. Due to the large radiative loss associated with dipolar coupling, however, the plasmonic-film-coupled nanocavities usually feature a low-quality factor, setting an ultimate limit of the increased light-matter interaction strength. Here, we demonstrate a plasmonic nanocavity composed of a metal-film-coupled nanoparticle dimer, exhibiting a significantly improved quality factor...
March 17, 2017: ACS Nano
https://www.readbyqxmd.com/read/28286946/reversible-redox-cycling-of-well-defined-ultrasmall-cu-cu2o-nanoparticles
#10
Sebastian D Pike, Edward R White, Anna Regoutz, Nicholas Sammy, David J Payne, Charlotte K Williams, Milo S P Shaffer
Exceptionally small and well-defined copper (Cu) and cuprite (Cu2O) nanoparticles (NPs) are synthesized by the reaction of mesitylcopper(I) with either H2 or air, respectively. In the presence of substoichiometric quantities of ligands, namely, stearic or di(octyl)phosphinic acid (0.1-0.2 equiv vs Cu), ultrasmall nanoparticles are prepared with diameters as low as ∼2 nm, soluble in a range of solvents. The solutions of Cu NPs undergo quantitative oxidation, on exposure to air, to form Cu2O NPs. The Cu2O NPs can be reduced back to Cu(0) NPs using accessible temperatures and low pressures of hydrogen (135 °C, 3 bar H2)...
March 13, 2017: ACS Nano
https://www.readbyqxmd.com/read/28256565/passion-fruit-like-nano-architectures-a-general-synthesis-route
#11
D Cassano, J David, S Luin, V Voliani
Noble metal nanostructures have demonstrated a number of intriguing features for both medicine and catalysis. However, accumulation issues have prevented their clinical translation, while their use in catalysis has shown serious efficiency and stability hurdles. Here we introduce a simple and robust synthetic protocol for passion fruit-like nano-architectures composed by a silica shell embedding polymeric arrays of ultrasmall noble metal nanoparticles. These nano-architectures show interesting features for both oncology and catalysis...
March 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28244734/ultrasmall-pt-nanoclusters-as-robust-peroxidase-mimics-for-colorimetric-detection-of-glucose-in-human-serum
#12
Lihua Jin, Zheng Meng, Yongqing Zhang, Shijie Cai, Zaihua Zhang, Cong Li, Li Shang, Yehua Shen
In this work, a new type of ultrasmall Pt nanoclusters (Pt NCs) was prepared via a facile one-pot approach by using yeast extract as the reductant and stabilizer. Besides their excellent water solubility, these yeast extract-stabilized Pt NCs also possess attractive peroxidase mimicking property. They can efficiently catalyze the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) in the coexistence of hydrogen peroxide (H2O2). Catalytic mechanism analysis suggested that the peroxidase mimicking activity of these Pt NCs might originate from their characteristic of accelerating electron transfer between TMB and H2O2, and their enzymatic kinetics followed typical Michaelis-Menten theory...
March 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28244304/synthesis-of-ultrasmall-platinum-nanoparticles-on-polymer-nanoshells-for-size-dependent-catalytic-oxidation-reactions
#13
Licheng Bai, Shumeng Zhang, Qiang Chen, Chuanbo Gao
It is highly desirable for the synthesis and stabilization of noble metal nanoparticles of uniform, precisely tunable sizes, especially in the range of angstroms to a few nanometers, for many catalytic applications in pursuit of optimal activity and selectivity. Herein, we report a novel strategy for the synthesis of uniform platinum (Pt) nanoparticles of ultrasmall sizes (average size: 0.9-2.3 nm), which are stabilized on hollow polymer nanoshells formed by polymerization of sodium dodecyl benzenesulfonate (SDBS) at the interface of an ethanol/water emulsion...
March 22, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28243561/colorimetric-gas-detection-by-the-varying-thickness-of-a-thin-film-of-ultrasmall-ptsa-coated-tio2-nanoparticles-on-a-si-substrate
#14
Urmas Joost, Andris Šutka, Meeri Visnapuu, Aile Tamm, Meeri Lembinen, Mikk Antsov, Kathriin Utt, Krisjanis Smits, Ergo Nõmmiste, Vambola Kisand
Colorimetric gas sensing is demonstrated by thin films based on ultrasmall TiO2 nanoparticles (NPs) on Si substrates. The NPs are bound into the film by p-toluenesulfonic acid (PTSA) and the film is made to absorb volatile organic compounds (VOCs). Since the color of the sensing element depends on the interference of reflected light from the surface of the film and from the film/silicon substrate interface, colorimetric detection is possible by the varying thickness of the NP-based film. Indeed, VOC absorption causes significant swelling of the film...
2017: Beilstein Journal of Nanotechnology
https://www.readbyqxmd.com/read/28231005/synaptic-plasticity-selectively-activated-by-polarization-dependent-energy-efficient-ion-migration-in-an-ultrathin-ferroelectric-tunnel-junction
#15
Chansoo Yoon, Ji Hye Lee, Sangik Lee, Ji Hoon Jeon, Jun Tae Jang, Dae Hwan Kim, Young Heon Kim, Bae Ho Park
Selectively activated inorganic synaptic devices, showing a high on/off ratio, ultrasmall dimensions, low power consumption, and short programming time, are required to emulate the functions of high-capacity and energy-efficient reconfigurable human neural systems combining information storage and processing ( Li et al. Sci. Rep. 2014 , 4 , 4096 ). Here, we demonstrate that such a synaptic device is realized using a Ag/PbZr0.52Ti0.48O3 (PZT)/La0.8Sr0.2MnO3 (LSMO) ferroelectric tunnel junction (FTJ) with ultrathin PZT (thickness of ∼4 nm)...
March 8, 2017: Nano Letters
https://www.readbyqxmd.com/read/28226244/molecularly-organic-inorganic-hybrid-hollow-mesoporous-organosilica-nanocapsules-with-tumor-specific-biodegradability-and-enhanced-chemotherapeutic-functionality
#16
Ping Huang, Yu Chen, Han Lin, Luodan Yu, Linlin Zhang, Liying Wang, Yufang Zhu, Jianlin Shi
Based on the intrinsic features of high stability and unique multifunctionality, inorganic nanoparticles have shown remarkable potentials in combating cancer, but their biodegradability and biocompatibility are still under debate. As a paradigm, this work successfully demonstrates that framework organic-inorganic hybridization can endow the inorganic mesoporous silica nanocarriers with unique tumor-sensitive biodegradability and high biocompatibility. Based on a "chemical homology" mechanism, molecularly organic-inorganic hybridized hollow mesoporous organosilica nanocapsules (HMONs) with high dispersity and sub-50 nm particle dimension were constructed in mass production...
February 15, 2017: Biomaterials
https://www.readbyqxmd.com/read/28225624/optical-observation-of-plasmonic-nonlocal-effects-in-a-2d-superlattice-of-ultrasmall-gold-nanoparticles
#17
Hao Shen, Li Chen, Lorenzo Ferrari, Meng-Hsien Lin, N Asger Mortensen, Shangjr Gwo, Zhaowei Liu
The advances in recent nanofabrication techniques have facilitated explorations of metal structures into nanometer scales, where the traditional local-response Drude model with hard-wall boundary conditions fails to accurately describe their optical responses. The emerging nonlocal effects in single ultrasmall silver nanoparticles have been experimentally observed in single-particle spectroscopy enabled by the unprecedented high spatial resolution of electron energy loss spectroscopy (EELS). However, unambiguous optical observation of such new effects in gold nanoparticles has yet not been reported, due to the extremely weak scattering and the obscuring fingerprint of strong interband transitions...
February 22, 2017: Nano Letters
https://www.readbyqxmd.com/read/28223074/recent-advances-in-biomedical-applications-of-fluorescent-gold-nanoclusters
#18
REVIEW
Youkun Zheng, Lanmei Lai, Weiwei Liu, Hui Jiang, Xuemei Wang
Fluorescent gold nanoclusters (AuNCs) are emerging as novel fluorescent materials and have attracted more and more attention in the field of biolabeling, biosensing, bioimaging and targeted cancer treatment because of their unusual physicochemical properties, such as long fluorescence lifetime, ultrasmall size, large Stokes shift, strong photoluminescence, as well as excellent biocompatibility and photostability. Recently, significant efforts have been committed to the preparation, functionalization and biomedical application studies of fluorescent AuNCs...
February 16, 2017: Advances in Colloid and Interface Science
https://www.readbyqxmd.com/read/28221761/ultrasmall-superbright-neodymium-upconversion-nanoparticles-via-energy-migration-manipulation-and-lattice-modification-808-nm-activated-drug-release
#19
Yan Zhang, Zhongzheng Yu, Jingqiu Li, Yanxiao Ao, Jingwen Xue, Zhiping Zeng, Xiangliang Yang, Timothy Thatt Yang Tan
Nd(3+)-sensitized upconversion nanoparticles are amongst the most promising emerging fluorescent nanotransducers. They are activated by 808 nm irradiation, which features merits such as limited tissue overheating and deeper penetration depth, hence attractive for diagnostic and therapeutic applications. Recent studies indicate that ultrasmall nanoparticles (<10 nm) are potentially more suitable for clinical application due to their favorable biodistribution and safety profiles. However, upconversion nanoparticles in the sub-10 nm range suffer from poor luminescence due to their ultrasmall size and greater proportion of lattice defects...
February 21, 2017: ACS Nano
https://www.readbyqxmd.com/read/28220897/uniformly-dispersed-znfe2o4-nanoparticles-on-nitrogen-modified-graphene-for-high-performance-supercapacitor-as-electrode
#20
Lei Li, Huiting Bi, Shili Gai, Fei He, Peng Gao, Yunlu Dai, Xitian Zhang, Dan Yang, Milin Zhang, Piaoping Yang
A facile strategy has been adopted for the preparation of ZnFe2O4/NRG composite by anchoring ultrasmall ZnFe2O4 nanoparticles on nitrogen-doped reduced graphene (denoted as NRG) for high-performance supercapacitor electrode. Remarkably, the growth of ZnFe2O4 nanocrystals, the reduction of graphitic oxide and the doping of nitrogen to graphene have been simultaneously achieved in one process. It is found that the NRG employed as substrate can not only control the formation of nano-sized ZnFe2O4, but also guarantee the high dispersion without any agglomeration...
February 21, 2017: Scientific Reports
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