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Silicon nanoparticles

Jinyoung Kang, Dokyoung Kim, Junxin Wang, Yunho Han, Jonathan M Zuidema, Ali Hariri, Ji-Ho Park, Jesse V Jokerst, Michael J Sailor
Photoacoustic (PA) imaging allows visualization of the physiology and pathology of tissues with good spatial resolution and relatively deep tissue penetration. The method converts near-infrared (NIR) laser excitation into thermal expansion, generating pressure transients that are detected with an acoustic transducer. Here, we find that the response of the PA contrast agent indocyanine green (ICG) can be enhanced 17-fold when it is sealed within a rigid nanoparticle. ICG encapsulated in particles composed of porous silicon (pSiNP), porous silica, or calcium silicate all show greater PA contrast relative to equivalent quantities of free ICG, with the pSiNPs showing the strongest enhancement...
May 21, 2018: Advanced Materials
Ngoc M Pham, Sebastian Rusch, Yuksel Temiz, Robert D Lovchik, Hans-Peter Beck, Walter Karlen, Emmanuel Delamarche
Point-of-care (POC) diagnostics are critically needed for the detection of infectious diseases, particularly in remote settings where accurate and appropriate diagnosis can save lives. However, it is difficult to implement immunoassays, and specifically immunoassays relying on signal amplification using silver staining, into POC diagnostic devices. Effective immobilization of antibodies in such devices is another challenge. Here, we present strategies for immobilizing capture antibodies (cAbs) in capillary-driven microfluidic chips and implementing a gold-catalyzed silver staining reaction...
May 21, 2018: Biomedical Microdevices
Hyeonglim Seo, Ikjang Choi, Nicholas Whiting, Jingzhe Hu, Quy Son Luu, Shivanand Pudakalakatti, Caitlin McCowan, Yaewon Kim, Niki Zacharias, Seunghyun Lee, Pratip Bhattacharya, Youngbok Lee
Porous silicon nanoparticles have recently garnered attention as potentially-promising biomedical platforms for drug delivery and medical diagnostics. Here, we demonstrate porous silicon nanoparticles as contrast agents for ²⁹Si magnetic resonance imaging. Size-controlled porous silicon nanoparticles were synthesized by magnesiothermic reduction of silica nanoparticles and were surface activated for further functionalization. Particles were hyperpolarized via dynamic nuclear polarization to enhance their ²⁹Si MR signals; the particles demonstrated long ²⁹Si spin-lattice relaxation (T₁) times (~ 25 mins), which suggests potential applicability for medical imaging...
May 20, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Tran Dieu Hang, Minh Tho Nguyen
(Abstract) Interaction, dissociation and dehydrogenation reactions of water monomer and dimer with pure and mixed tetrameric silicon clusters Si3X with X = Si, Be, Mg, Ca were investigated using high accuracy quantum chemical calculations. While geometries were optimized using the DFT/B3LYP functional with the aug-cc-pVTZ basis set, reaction energy profiles were constructed making use of the coupled-cluster theory with extrapolation to complete basis set, CCSD(T)/CBS. Cleavage of the O-H bond in water dimer is found to be more favored than that of water monomer in the reaction with Si4...
May 18, 2018: Journal of Physical Chemistry. A
Wen Liu, Yalun Wang, Xiao Han, Ping Lu, Liang Zhu, Chaowei Sun, Jun Qian, Sailing He
Near-infrared (NIR) fluorescence is very important for high-contrast biological imaging of high-scattering tissues such as brain tissue. Unfortunately, commercial NIR dyes are excited usually by visible light, and their multi-photon absorption (MPA) cross-sections are small. Here, we design new co-encapsulated NIR nanoparticles (NPs) with a large three-photon (3PA) absorption cross-section. A form of aggregation-induced emission (AIE) luminogen (AIEgen), 2,3-bis(4'-(diphenylamino)-[1,1'-biphenyl]-4-yl) fumaronitrile (TPATCN), is introduced as the donor, and a form of NIR dye, silicon 2,3-naphthalocyanine bis-(trihexylsilyloxide) (NIR775), is adopted as the acceptor...
May 18, 2018: Nanoscale
C Pin, J-B Jager, M Tardif, E Picard, E Hadji, F de Fornel, B Cluzel
Fourteen years ago, optical lattices and holographic tweezers were considered as a revolution, allowing for trapping and manipulating multiple particles at the same time using laser light. Since then, near-field optical forces have aroused tremendous interest as they enable efficient trapping of a wide range of objects, from living cells to atoms, in integrated devices. Yet, handling at will multiple objects using a guided light beam remains a challenging task for current on-chip optical trapping techniques...
May 18, 2018: Lab on a Chip
Byungji Kim, Hong-Bo Pang, Jinyoung Kang, Ji-Ho Park, Erkki Ruoslahti, Michael J Sailor
The incidence of adverse effects and pathogen resistance encountered with small molecule antibiotics is increasing. As such, there is mounting focus on immunogene therapy to augment the immune system's response to infection and accelerate healing. A major obstacle to in vivo gene delivery is that the primary uptake pathway, cellular endocytosis, results in extracellular excretion and lysosomal degradation of genetic material. Here we show a nanosystem that bypasses endocytosis and achieves potent gene knockdown efficacy...
May 17, 2018: Nature Communications
E Mitsai, A Kuchmizhak, E Pustovalov, A Sergeev, A Mironenko, S Bratskaya, D P Linklater, A Balčytis, E Ivanova, S Juodkazis
All-dielectric resonant micro- and nano-structures made of high-index dielectrics have recently emerged as a promising surface-enhanced Raman scattering (SERS) platform which can complement or potentially replace the metal-based counterparts in routine sensing measurements. These unique structures combine the highly-tunable optical response and high field enhancement with the non-invasiveness, i.e. chemically non-perturbing the analyte, simple chemical modification and recyclability. Meanwhile, commercially competitive fabrication technologies for mass production of such structures are still missing...
May 16, 2018: Nanoscale
Mansour Almansour, Saud Alarifi, Bashir Jarrar
Background: Silicon dioxide (silica) nanoparticles (SDNPs) are widely used in nanotechnology and medicine, but these nanomaterials may carry a high risk for human health while little is known about their toxicity. Methods: We investigated the alterations in morphometry, biochemistry, hematology, histology of liver tissue and gene expression of drug-metabolizing enzymes induced by 10-nm SDNPs. Healthy male Wistar albino rats were exposed to 20, 35 and 50 repeated injections of SDNPs (2 mg/kg body weight)...
2018: International Journal of Nanomedicine
J S Gebauer, V Mackert, S Ognjanović, M Winterer
There is a growing interest in science and industry for printed electronics. Printed electronics enable the production of large quantities of electronic components at low cost. Even though organic semiconductors are already widely used for printed components, inorganic materials may be advantageous due to their higher durability and superior device performance. Nevertheless, inorganic materials still remain difficult to print making the development of printable and functional inks a necessity. In this work we present the formulation, inkjet printing and processing of newly developed inks based on ethylene glycol as dispersion medium...
May 4, 2018: Journal of Colloid and Interface Science
Christopher Jay T Robidillo, Muhammad Amirul Islam, Maryam Aghajamali, Angelique Faramus, Regina Sinelnikov, Xiyu Zhang, Job Boekhoven, Jonathan G C Veinot
This study reports the preparation of functional bioinorganic hybrid materials exhibiting catalytic activity and photoluminescent properties arising from the combination of enzymes and freestanding silicon-based nanoparticles. The hybrid materials reported herein have potential applications in biological sensing/imaging and theranostics as they combine long-lived silicon-based nanoparticle photoluminescence with substrate-specific enzymatic activity. Thermal hydrosilylation of undecenoic acid and alkene-terminated poly(ethylene oxide) with hydride-terminated silicon nanocrystals afforded nanoparticles functionalized with a mixed surface made up of carboxylic acid and poly(ethylene oxide) moieties...
May 14, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Xiaoyong Qiang, Ming Hu, Boshuo Zhao, Yue Qin, Ran Yang, Liwei Zhou, Yuxiang Qin
The decoration of noble metal nanoparticles (NPs) on the surface of metal oxide semiconductors to enhance material characteristics and gas-sensing performance has recently attracted increasing attention from researchers worldwide. Here, we have synthesized porous silicon (PS)/WO₃ nanorods (NRs) functionalized with Pd NPs to enhance NO₂ gas-sensing performance. PS was first prepared using electrochemical methods and worked as a substrate. WO₃ NRs were synthesized by thermally oxidizing W film on the PS substrate...
May 10, 2018: Materials
Henry Holland-Moritz, Julia Graupner, Wolfhard Moeller, Claudia Pacholski, Carsten Ronning
If nanostructures are irradiated with energetic ions, the mechanism of sputtering becomes important when the ion range matches about the size of the nanoparticle. Gold nanoparticles with diameters of ~50 nm on top of silicon substrates with a native oxide layer were irradiated by Gallium ions with energies ranging from 1 to 30 keV in a focused ion beam system. High resolution in-situ scanning electron microscopy imaging permits detailed insights in the dynamics of the morphology change and sputter yield. Compared to bulk-like structures or thin films, a pronounced shaping and enhanced sputtering in the nanostructures occurs, which enables a specific shaping of these structures using ion beams...
May 9, 2018: Nanotechnology
Ghazal Darfarin, Roya Salehi, Effat Alizadeh, Behnam Nasiri Motlagh, Abolfazl Akbarzadeh, Alireza Farajollahi
INTRODUCTION: Recently it has been shown that radiation dose enhancement could be achievable in radiotherapy using nanoparticles (NPs). In this study, evaluation was made to determine efficiency of gold-silica shell-core NP in megavoltage irradiation of MCF7 breath cancer cells. MATERIALS AND METHODS: Gold-silicon oxide shell-core NPs were obtained by conjugation of gold NP with amine or thiol functionalized silica NPs (AuN@SiO2 and AuS@SiO2 ). Cellular uptake and cytotoxicity of NPs were examined by fluorescent microscopy and MTT assay, respectively...
May 9, 2018: Artificial Cells, Nanomedicine, and Biotechnology
Daniel Torres-Lagares, Lizett Castellanos-Cosano, Maria-Angeles Serrera-Figallo, Carmen López-Santos, Angel Barranco, Agustín Rodríguez-González-Elipe, Jose-Luis Gutierrez-Perez
(1) Background: The use of physical barriers to prevent the invasion of gingival and connective tissue cells into bone cavities during the healing process is called guided bone regeneration. The objective of this in-vitro study was to compare the growth of human osteoblasts on Poly(Lactic⁻co⁻Glycolic) (PLGA) membranes modified with oxygen plasma and Hydroxyapatite (HA), silicon dioxide (SiO₂), and titanium dioxide (TiO₂) composite nanoparticles, respectively. (2) Methods: All the membranes received a common treatment with oxygen plasma and were subsequently treated with HA nanostructured coatings (n = 10), SiO₂ (n = 10) and TiO₂ (n = 10), respectively and a PLGA control membrane (n = 10)...
May 8, 2018: Materials
Wei Yang, Xiangyang Lei, Haohao Hui, Qinghua Zhang, Xueran Deng
Moisture-resistant silicone coatings were prepared on the surface of potassium dihydrogen phosphate (KDP) crystal by means of spin-coating, in which hydrophobic-modified SiO₂ nanoparticles were embedded in a certain proportion. The refractive index of such coating can be tuned arbitrarily in the range of 1.21⁻1.44, which endows the KDP optical component with excellent transmission capability as well as the moisture proof effect. A dual-layer anti-reflective coating system was obtained by covering this silicone coating with a porous SiO₂ coating which is specially treated to enhance the moisture resistance...
May 7, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Bharat Bhushan, Samuel Martin
Superliquiphobic surfaces that exhibit self-cleaning, antifouling, finger touch resistance, and low drag properties with high transparency are of interest in industrial applications including optical devices, solar panels, and self-cleaning windows. In this paper, an overview of coatings using a simple and scalable fabrication technique are presented that exhibit superoleophobic/philic properties, wear resistance, finger touch resistance, and transparency. The coating comprises hydrophobic SiO2 nanoparticles with a binder of methylphenyl silicone resin...
April 27, 2018: Journal of Colloid and Interface Science
Emma Westas Janco, Mats Hulander, Martin Andersson
The aim of this study was to investigate how the size of nanosized surface features affect classical immune complement activation through adsorption of IgG and the following binding of C1q. By using model surfaces with immobilized SiO2 nanoparticles of different sizes (8, 32 and 68 nm in diameter), three different curvatures with the same chemistry was systematically studied and analyzed using the acoustic sensing technique; Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D). Circular Dichroism (CD) was employed to study any changes in the secondary structure of IgG using a methodology with stacked functionalized substrates...
April 30, 2018: Acta Biomaterialia
Gabriella Dravecz, Tibor Z Jánosi, Dávid Beke, Dániel Á Major, Gyula Károlyházy, János Erostyák, Katalin Kamarás, Ádám Gali
Ultrasmall silicon carbide nanoparticles (SiC USNPs) are very promising biomarkers for developing new applications in diagnostics, cell monitoring or drug delivery, even though their interaction with biological molecules such as different proteins has not yet been investigated in detail. In this study, the biological behaviour of SiC USNPs in a medium modeling a living organism was investigated in detail through the dependence of the fluorescence on interactions between bovine serum albumin (BSA) and SiC USNPs...
May 3, 2018: Physical Chemistry Chemical Physics: PCCP
Sebastian Schön, Regine von Klitzing
Background: The ordering of molecules or particles in the vicinity of a confining surface leads to the formation of an interfacial region with layers of decreasing order normal to the confining surfaces. The overlap of two interfacial regions gives rise to the well-known phenomenon of oscillatory structural forces. These forces are commonly fitted with an exponentially decaying harmonic oscillation as introduced by Israelachvili (Israelachvili, J. N. Intermolecular & surface forces; Academic Press: San Diego, CA, USA, 1985)...
2018: Beilstein Journal of Nanotechnology
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