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Silicon nanoparticles

M Decker, T Pertsch, I Staude
We study resonant photonic-plasmonic coupling between a gold dipole nanoantenna and a silicon nanodisc supporting electric and magnetic dipolar Mie-type resonances. Specifically, we consider two different cases for the mode structure of the silicon nanodisc, namely spectrally separate and spectrally matching electric and magnetic dipolar Mie-type resonances. In the latter case, the dielectric nanoparticle scatters the far fields of a unidirectional Huygens' source. Our results reveal an anticrossing of the plasmonic dipole resonance and the magnetic Mie-type dipole resonance of the silicon nanodisc, accompanied by a clear signature of photonic-plasmonic mode hybridization in the corresponding mode profiles...
March 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Elizaveta V Melik-Gaykazyan, Maxim R Shcherbakov, Alexander S Shorokhov, Isabelle Staude, Igal Brener, Dragomir N Neshev, Yuri S Kivshar, Andrey A Fedyanin
Subwavelength silicon nanoparticles are known to support strongly localized Mie-type modes, including those with resonant electric and magnetic dipolar polarizabilities. Here we compare experimentally the efficiency of the third-harmonic generation from isolated silicon nanodiscs for resonant excitation at the two types of dipolar resonances. Using nonlinear spectroscopy, we observe that the magnetic dipolar mode yields more efficient third-harmonic radiation in contrast to the electric dipolar (ED) mode. This is further supported by full-wave numerical simulations, where the volume-integrated local fields and the directly simulated nonlinear response are shown to be negligible at the ED resonance compared with the magnetic one...
March 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Svetlana N Shevchenko, Markus Burkhardt, Eugene V Sheval, Ulyana A Natashina, Christina Große, Alexander L Nikolaev, Alexander V Gopin, Ute Neugebauer, Andrew A Kudryavtsev, Vladimir Sivakov, Liubov Andreevna Osminkina
In this study, we report on a method for suppressing of Escherichia coli (E.coli) vitality by means of therapeutic ultrasound irradiation (USI) using biocompatible silicon nanoparticles as cavitation sensitizers. Silicon nanoparticles without (SiNPs) and with polysaccharide (dextran) coating (DSiNPs) were used. Both types of nanoparticles were non-toxic to Hep 2 cells up to concentration of 2 mg/ml. The treatment of bacteria with nanoparticles and application of 1 W/cm2 USI resulted in reduction of their viability up to 35% and 72% for SiNPs and DSiNPs, respectively...
February 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
J Jiménez-Villarreal, D I Rivas-Armendáriz, R D Arellano Pérez-Vertti, E Olivas Calderón, R García-Garza, N D Betancourt-Martínez, L B Serrano-Gallardo, J Morán-Martínez
At present, the use of nanoparticles is a controversial topic, especially when analyzing their effects in human tissues. Nanoparticles (NPs) can cause oxidative stress by increasing membrane lipids peroxidation and reactive oxygen species, and decreasing intracellular glutathione. Oxidative stress plays an important role in cell signaling and inflammatory responses. It can result in genotoxicity, affect cell proliferation, and induce DNA damage. The objective of this study is to evaluate the genotoxic potential of NPs in lymphocyte DNA...
February 8, 2017: Genetics and Molecular Research: GMR
C F McGee, S Storey, N Clipson, E Doyle
Soil microorganisms are key contributors to nutrient cycling and are essential for the maintenance of healthy soils and sustainable agriculture. Although the antimicrobial effects of a broad range of nanoparticulate substances have been characterised in vitro, little is known about the impact of these compounds on microbial communities in environments such as soil. In this study, the effect of three widely used nanoparticulates (silver, silicon dioxide and aluminium oxide) on bacterial and fungal communities in an agricultural pastureland soil was examined in a microcosm-based experiment using a combination of enzyme analysis, molecular fingerprinting and amplicon sequencing...
February 14, 2017: Ecotoxicology
Taeho Kim, Xin Fu, David Warther, Michael J Sailor
Porous silicon nanoparticles containing both Pd and iron oxide nanoparticles are prepared and studied as magnetically recoverable catalysts for organic reductions. The Pd nanoparticles are generated in situ by electroless deposition of Pd(NH3)4(2+), where the porous Si skeleton acts as both a template and as a reducing agent and the released ammonia ligands raise the local pH to exert control over the size of the Pd nanoparticles. The nanocomposites are characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), nitrogen adsorption, X-ray diffraction (XRD), superconducting quantum interference device (SQUID) magnetization, and dynamic light scattering (DLS)...
February 14, 2017: ACS Nano
Hailong Zhang, Wei Zhang, Yong Zhou, Yuhua Jiang, Shupeng Li
Radiotherapy is a critical strategy and standard adjuvant approach to glioblastoma treatment. One of the major challenges facing radiotherapy is to minimize radiation damage to normal tissue without compromising therapeutic effects on cancer cells. Various agents and numerous approaches have been developed to improve the therapeutic index of radiotherapy. Among them, radiosensitizers have attracted much attention because they selectively increase susceptibility of cancer cells to radiation and thus enhance biological effectiveness of radiotherapy...
February 10, 2017: Translational Oncology
Yangxia Han, Yonglei Chen, Jie Feng, Juanjuan Liu, Sudai Ma, Xingguo Chen
Because 2,4,6-trinitrophenol (TNP) and its analogues such as 2,4,6-trinitrotoluene (TNT) possess similar chemical structures and properties, the reliable and accurate detection of TNP from its analogues still remains a challenging task. In the present work, a selective and sensitive method based on the water-soluble silicon nanoparticles (SiNPs) for the determination of TNP was established. The SiNPs with good thermostability and excellent antiphotobleaching capability were prepared via a simple one-pot method...
February 21, 2017: Analytical Chemistry
Seung Jong Lee, Hye Jin Kim, Tae Hoon Hwang, Sunghun Choi, Sung Hyeon Park, Erhan Deniz, Dae Soo Jung, Jang Wook Choi
Despite the high theoretical capacity, silicon (Si) anodes in lithium-ion batteries have difficulty in meeting the commercial standards in various aspects. In particular, the huge volume change of Si makes it very challenging to simultaneously achieve high initial Coulombic efficiency (ICE) and long-term cycle life. Herein, we report spray pyrolysis to prepare Si-SiOx composite using an aqueous precursor solution containing Si nanoparticles, citric acid, and sodium hydroxide (NaOH). In the precursor solution, Si nanoparticles are etched by NaOH with the production of [SiO4]4-...
February 13, 2017: Nano Letters
Yan-Kai Tzeng, Jingyuan Linda Zhang, Haiyu Lu, Hitoshi Ishiwata, Jeremy Dahl, Robert M K Carlson, Hao Yan, Peter R Schreiner, Jelena Vuckovic, Zhi-Xun Shen, Nicholas A Melosh, Steven Chu
Color center-containing nanodiamonds have many applications in quantum technologies and biology. Diamondoids, molecular-sized diamonds have been used as seeds in Chemical Vapor Deposition (CVD) growth. However, optimizing growth conditions to produce high crystal quality nanodiamonds with color centers requires varying growth conditions that often leads to ad-hoc and time-consuming, one-at-a-time testing of reaction conditions. In order to rapidly explore parameter space, we developed a microwave plasma CVD technique using a vertical, rather than horizontally oriented stage-substrate geometry...
February 9, 2017: Nano Letters
Liangbiao Wang, Qinglin Cheng, Hengfei Qin, Zhongchun Li, Zhengsong Lou, Juanjuan Lu, Junhao Zhang, Quanfa Zhou
Resource utilization of waste plastic could solve the problem of environmental pollution and simultaneously relieve energy shortages, achieving sustainable development. In this study, the conversion of waste polytetrafluoroethylene (PTFE) to cubic silicon carbide (SiC) nanoparticles has been described. The structures and morphologies of the obtained SiC were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Furthermore, the FTIR spectrum of the obtained SiC sample suggests that the waste PTFE was completely converted into SiC in our approach...
February 9, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
A P Sviridov, L A Osminkina, A Yu Kharin, M B Gongansky, J V Kargina, A A Kudryavtsev, Yu I Bezsudnova, T S Perova, A Geloen, V Lysenko, V Yu Timoshenko
Silicon nanoparticles (SiNPs) prepared by mechanical grinding of luminescent porous silicon were coated with a biopolymer (dextran) and investigated as a potential theranostic agent for bioimaging and sonodynamic therapy. Transmission electron microscopy, photoluminescence and Raman scattering measurements of dextran-coated SiNPs gave evidence of their enhanced stability in water. In vitro experiments confirmed the lower cytotoxicity of the dextran-coated NPs in comparison with uncoated ones, especially for high concentrations of about 2 mg ml(-1)...
March 10, 2017: Nanotechnology
Han Gao, Lisong Xiao, Ingo Plümel, Gui-Liang Xu, Yang Ren, Xiaobing Zuo, Yuzi Liu, Christof Schulz, Hartmut Wiggers, Khalil Amine, Zonghai Chen
When designing nano-Si electrodes for lithium-ion batteries, the detrimental effect of the c-Li15Si4 phase formed upon full lithiation is often a concern. In this study, Si nanoparticles with controlled particle sizes and morphology were synthesized and parasitic reactions of the metastable c-Li15Si4 phase with the non-aqueous electrolyte was investigated. The use of smaller Si nanoparticles (~ 60 nm) and the addition of fluoroethylene carbonate additive played decisive roles in the parasitic reactions such that the c-Li15Si4 phase could disappear at the end of lithiation...
February 8, 2017: Nano Letters
Daksh Agarwal, Carlos Aspetti, Matteo Cargnello, Mingliang Ren, Jinkyoung Yoo, Christopher B Murray, Ritesh Agarwal
The field of plasmonics has attracted considerable attention in recent years because of potential applications in various fields such as nanophotonics, photovoltaics, energy conversion, catalysis and therapeutics. It is becoming increasing clear that intrinsic high losses associated with plasmons can be utilized to create new device concepts to harvest the generated heat. It is therefore important to design cavities, which can harvest optical excitations efficiently to generate heat. We report a highly engineered nanowire cavity, which utilizes a high dielectric silicon core with a thin plasmonic film (Au) to create an effective metallic cavity to strongly confine light, which when coupled with localized surface plasmons in the nanoparticles of the thin metal film produces exceptionally high temperatures upon laser irradiation...
February 6, 2017: Nano Letters
Houyu Wang, Yao He
During the past decades, owing to silicon nanomaterials' unique optical properties, benign biocompatibility, and abundant surface chemistry, different dimensional silicon nanostructures have been widely employed for rationally designing and fabricating high-performance fluorescent sensors for the detection of various chemical and biological species. Among of these, zero-dimensional silicon nanoparticles (SiNPs) and one-dimensional silicon nanowires (SiNWs) are of particular interest. Herein, we focus on reviewing recent advances in silicon nanomaterials-based fluorescent sensors from a broad perspective and discuss possible future directions...
February 3, 2017: Sensors
Mohammad-Ali Shahbazi, Patrick Vingadas Almeida, Alexandra Correia, Barbara Herranz-Blanco, Neha Shrestha, Ermei Mäkilä, Jarno Salonen, Jouni Hirvonen, Hélder A Santos
Bioresponsive cytosolic nanobased multidelivery has been emerging as an enormously challenging novel concept due to the intrinsic protective barriers of the cells and hardly controllable performances of nanomaterials. Here, we present a new paradigm to advance nano-in-nano integration technology amenable to create multifunctional nanovehicles showing considerable promise to overcome restrictions of intracellular delivery, solve impediments of endosomal localization and aid effectual tracking of nanoparticles...
February 1, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
Soo Kyung Lee, Chee Leong Tan, Yong Tak Lee
We report the application of gold and silver (AuAg) bimetallic non-alloyed nanoparticles (BNNPs) on disordered subwavelength structures (d-SWSs). The combined advantages of the plasmonic structures and d-SWSs improved the light trapping performance of flexible thin film crystalline silicon (c-Si) solar cells. Antireflective d-SWSs were fabricated using spin-coated Ag ink and subsequent metal-assisted chemical etching, which reduced the ion-induced surface damage produced by the dry etching process. The dimensions of the d-SWSs were finely tuned by adjusting the Ag ink ratio...
February 1, 2017: Optics Letters
Lei Wang, Sergey Kruk, Lei Xu, Mohsen Rahmani, Daria Smirnova, Alexander Solntsev, Ivan Kravchenko, Dragomir Neshev, Yuri Kivshar
Recent progress in the study of resonant light confinement in high-index dielectric nanostructures suggests a new route for achieving efficient control of both electric and magnetic components of light. It also leads to the enhancement of nonlinear effects near electric and magnetic Mie resonances with an engineered radiation directionality. Here we study the third-harmonic generation from dimers composed of pairs of two identical silicon nanoparticles and demonstrate, both numerically and experimentally, that the multipolar harmonic modes generated by the dimers near the Mie resonances allow the shaping of the directionality of nonlinear radiation...
February 1, 2017: Nanoscale
Dalibor Breznan, Dharani D Das, Julie S O'Brien, Christine MacKinnon-Roy, Surendra Nimesh, Ngoc Q Vuong, Stéphane Bernatchez, Nimal DeSilva, Myriam Hill, Prem Kumarathasan, Renaud Vincent
The likelihood of environmental and health impacts of silicon dioxide nanoparticles (SiNPs) has risen, due to their increased use in products and applications. The biological potency of a set of similarly-sized amorphous SiNPs was investigated in a variety of cells to examine the influence of physico-chemical and biological factors on their toxicity. Cellular LDH and ATP, BrdU incorporation, resazurin reduction and cytokine release were measured in human epithelial A549, human THP-1 and mouse J774A.1 macrophage cells exposed for 24 h to suspensions of 5-15, 10-20 and 12 nm SiNPs and reference particles...
February 1, 2017: Nanotoxicology
Haiying Tang, Dan Xiang, Feng Wang, Jingwei Mao, Xiaoyan Tan, Yingde Wang
The targeting of 5-aminosalicylic acid (5-ASA), a first-line therapeutic agent for mild to moderate active ulcerative colitis (UC), to the site of inflammation has remained a challenge and an unmet requirement in the treatment of UC. However, nanoscale carriers for targeted drug delivery are promising for pharmacotherapy, and nanoparticles improve the pharmacokinetics of the loaded therapeutics based on their physical properties. To design and prepare 5‑ASA‑loaded silicon dioxide nanoparticles (5‑ASA‑SiO2 NPs), a micro‑emulsion method was conducted, and their respective therapeutic effects were validated in a mouse model of UC...
January 26, 2017: Molecular Medicine Reports
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