Highly cytocompatible and flexible three-dimensional graphene/polydimethylsiloxane composite for culture and electrochemical detection of L929 fibroblast cells.

PubMed

Waiwijit, Uraiwan; Maturos, Thitima; Pakapongpan, Saithip; Phokharatkul, Ditsayut; Wisitsoraat, Anurat; Tuantranont, Adisorn

2016-08-01

Recently, three-dimensional graphene interconnected network has attracted great interest as a scaffold structure for tissue engineering due to its high biocompatibility, high electrical conductivity, high specific surface area and high porosity. However, free-standing three-dimensional graphene exhibits poor flexibility and stability due to ease of disintegration during processing. In this work, three-dimensional graphene is composited with polydimethylsiloxane to improve the structural flexibility and stability by a new simple two-step process comprising dip coating of polydimethylsiloxane on chemical vapor deposited graphene/Ni foam and wet etching of nickel foam. Structural characterizations confirmed an interconnected three-dimensional multi-layer graphene structure with thin polydimethylsiloxane scaffold. The composite was employed as a substrate for culture of L929 fibroblast cells and its cytocompatibility was evaluated by cell viability (Alamar blue assay), reactive oxygen species production and vinculin immunofluorescence imaging. The result revealed that cell viability on three-dimensional graphene/polydimethylsiloxane composite increased with increasing culture time and was slightly different from a polystyrene substrate (control). Moreover, cells cultured on three-dimensional graphene/polydimethylsiloxane composite generated less ROS than the control at culture times of 3-6 h. The results of immunofluorescence staining demonstrated that fibroblast cells expressed adhesion protein (vinculin) and adhered well on three-dimensional graphene/polydimethylsiloxane surface. Good cell adhesion could be attributed to suitable surface properties of three-dimensional graphene/polydimethylsiloxane with moderate contact angle and small negative zeta potential in culture solution. The results of electrochemical study by cyclic voltammetry showed that an oxidation current signal with no apparent peak was induced by fibroblast cells and the oxidation current at an

Multicolored redox active upconverter cerium oxide nanoparticle for bio-imaging and therapeutics†

PubMed Central

Babu, Suresh; Cho, Jung-Hyun; Dowding, Janet M.; Heckert, Eric; Komanski, Chris; Das, Soumen; Colon, Jimmie; Baker, Cheryl H.; Bass, Michael; Self, William T.; Seal, Sudipta

2011-01-01

Cytocompatible, co-doped cerium oxide nanoparticles exhibited strong upconversion properties that were found to kill lung cancer cells by inducing apoptosis thereby demonstrating the potential to be used as clinical contrast agents for imaging and as therapeutic agents for treatment of cancer. PMID:20683524

Immobilization of Ag nanoparticles/FGF-2 on a modified titanium implant surface and improved human gingival fibroblasts behavior.

PubMed

Ma, Qianli; Mei, Shenglin; Ji, Kun; Zhang, Yumei; Chu, Paul K

2011-08-01

The objective of this study was to form a rapid and firm soft tissue sealing around dental implants that resists bacterial invasion. We present a novel approach to modify Ti surface by immobilizing Ag nanoparticles/FGF-2 compound bioactive factors onto a titania nanotubular surface. The titanium samples were anodized to form vertically organized TiO(2) nanotube arrays and Ag nanoparticles were electrodeposited onto the nanotubular surface, on which FGF-2 was immobilized with repeated lyophilization. A uniform distribution of Ag nanoparticles/FGF-2 was observed on the TiO(2) nanotubular surface. The L929 cell line was used for cytotoxicity assessment. Human gingival fibroblasts (HGFs) were cultured on the modified surface for cytocompatibility determination. The Ag/FGF-2 immobilized samples displayed excellent cytocompatibility, negligible cytotoxicity, and enhanced HGF functions such as cell attachment, proliferation, and ECM-related gene expression. The Ag nanoparticles also exhibit some bioactivity. In conclusion, this modified TiO(2) nanotubular surface has a large potential for use in dental implant abutment. Copyright © 2011 Wiley Periodicals, Inc.

Development of various composition multicomponent chitosan/fish collagen/glycerin 3D porous scaffolds: Effect on morphology, mechanical strength, biostability and cytocompatibility.

PubMed

Ullah, Saleem; Zainol, Ismail; Chowdhury, Shiplu Roy; Fauzi, M B

2018-05-01

The various composition multicomponent chitosan/fish collagen/glycerin 3D porous scaffolds were developed and investigated the effect of various composition chitosan/fish collagen/glycerin on scaffolds morphology, mechanical strength, biostability and cytocompatibility. The scaffolds were fabricated via freeze-drying technique. The effects of various compositions consisting in 3D scaffolds were investigated via FT-IR analysis, porosity, swelling and mechanical tests, and effect on the morphology of scaffolds investigated microscopically. The biostability and cytocompatibility tests were used to explore the ability of scaffolds to use for tissue engineering application. The average pore sizes of scaffolds were in range of 100.73±27.62-116.01±52.06, porosity 71.72±3.46-91.17±2.42%, tensile modulus in dry environment 1.47±0.08-0.17±0.03MPa, tensile modulus in wet environment 0.32±0.03-0.14±0.04MPa and biodegradation rate (at day 30) 60.38±0.70-83.48±0.28%. In vitro culture of human fibroblasts and keratinocytes showed that the various composition multicomponent 3D scaffolds were good cytocompatibility however, the scaffolds contained high amount of fish collagen excellently facilitated cell proliferation and adhesion. It was found that the high amount fish collagen and glycerin scaffolds have high porosity, enough mechanical strength and biostability, and excellent cytocompatibility. Copyright © 2018 Elsevier B.V. All rights reserved.

Interfacial Characteristics and Cytocompatibility of Hydraulic Sealer Cements.

PubMed

Kebudi Benezra, Mira; Schembri Wismayer, Pierre; Camilleri, Josette

2018-06-01

The stability and long-term success of root canal obturation depends on the choice of sealer because the sealer bonds to the dentin and stabilizes the solid cone. Furthermore, the sealer needs to be nontoxic because sealer toxicity will certainly lead to treatment failure. The aim of this study was to assess the sealer-dentin interface of 3 hydraulic root canal sealers and to evaluate their cytocompatibility compared with AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany). Four dental root canal sealers were assessed. AH Plus, MTA Fillapex (Angelus, Londrina, Brazil), BioRoot RCS (Septodont, Saint-Maur-des-Fossés, France), and Endoseal (Maruchi, Wonju-si, Gangwon-do, South Korea) were characterized using scanning electron microscopy and energy-dispersive spectroscopy. The sealer-tooth interface was assessed by confocal microscopy and scanning electron microscopy, and biocompatibility was measured by assessing the cell metabolic function using direct contact assays and alkaline phosphatase activity. The tricalcium silicate-based sealers presented a different microstructure and elemental composition despite their similar chemistry and classification. BioRoot RCS was free of aluminum, and all sealers presented different radiopacifying elements. The sealer penetration in the dentinal tubules and interfacial characteristics were different. The migration of silicon was evident from sealer to tooth for all sealers containing tricalcium silicate. MTA Fillapex and BioRoot RCS exhibited the best cytocompatibility in both the direct contact test and alkaline phosphatase activity. The use of hydraulic calcium silicate-based sealers has introduced a different material type to endodontics. These materials are different than other sealers mostly because of their hydraulic nature and their interaction with the environment. Although the sealers tested had a similar chemistry, their cytocompatibility and bonding mechanisms were diverse. Copyright © 2017 American Association of

Mechanically-competent and cytocompatible polycaprolactone-borophosphosilicate hybrid biomaterials.

PubMed

Mondal, Dibakar; Dixon, S Jeffrey; Mequanint, Kibret; Rizkalla, Amin S

2017-11-01

Organic-inorganic class II hybrid materials have domain sizes at the molecular level and chemical bonding between the organic and inorganic phases. We have previously reported the synthesis of class II hybrid biomaterials from alkoxysilane-functionalized polycaprolactone (PCL) and borophosphosilicate (B 2 O 3 -P 2 O 5 -SiO 2 ) glass (BPSG) through a non-aqueous sol-gel process. In the present study, the mechanical properties and degradability of these PCL/BPSG hybrid biomaterials were studied and compared to those of their conventional composite counterparts. The compressive strength, modulus and toughness of the hybrid biomaterials were significantly greater compared to the conventional composites, likely due to the covalent bonding between the organic and inorganic phases. A hybrid biomaterial (50wt% PCL and 50wt% BPSG) exhibited compressive strength, modulus and toughness values of 32.2 ± 3.5MPa, 573 ± 85MPa and 1.54 ± 0.03MPa, respectively; whereas the values for composite of similar composition were 18.8 ± 1.6MPa, 275 ± 28MPa and 0.76 ± 0.03MPa, respectively. Degradation in phosphate-buffered saline was slower for hybrid biomaterials compared to their composite counterparts. Thus, these hybrid materials possess superior mechanical properties and more controlled degradation characteristics compared to their corresponding conventional composites. To assess in vitro cytocompatibility, MC3T3-E1 pre-osteoblastic cells were seeded onto the surfaces of hybrid biomaterials and polycaprolactone (control). Compared to polycaprolactone, cells on the hybrid material displayed enhanced spreading, focal adhesion formation, and cell number, consistent with excellent cytocompatibility. Thus, based on their mechanical properties, degradability and cytocompatibility, these novel biomaterials have potential for use as scaffolds in bone tissue engineering and related applications. Copyright © 2017. Published by Elsevier Ltd.

Effect of barium-coated halloysite nanotube addition on the cytocompatibility, mechanical and contrast properties of poly(methyl methacrylate) cement.

PubMed

Jammalamadaka, Uday; Tappa, Karthik; Weisman, Jeffery A; Nicholson, James Connor; Mills, David K

2017-01-01

Halloysite nanotubes (HNTs) were investigated as a platform for tunable nanoparticle composition and enhanced opacity in poly(methyl methacrylate) (PMMA) bone cement. Halloysite has been widely used to increase the mechanical properties of various polymer matrices, in stark contrast to other fillers such as barium sulfate that provide opacity but also decrease mechanical strength. The present work describes a dry deposition method for successively fabricating barium sulfate nanoparticles onto the exterior surface of HNTs. A sintering process was used to coat the HNTs in barium sulfate. Barium sulfate-coated HNTs were then added to PMMA bone cement and the samples were tested for mechanical strength and tailored opacity correlated with the fabrication ratio and the amount of barium sulfate-coated HNTs added. The potential cytotoxic effect of barium-coated HNTs in PMMA cement was also tested on osteosarcoma cells. Barium-coated HNTs were found to be completely cytocompatible, and cell proliferation was not inhibited after exposure to the barium-coated HNTs embedded in PMMA cement. We demonstrate a simple method for the creation of barium-coated nanoparticles that imparted improved contrast and material properties to native PMMA. An easy and efficient method for coating clay nanotubes offers the potential for enhanced imaging by radiologists or orthopedic surgeons.

Surface modification of poly(L-lactic acid) to improve its cytocompatibility via assembly of polyelectrolytes and gelatin.

PubMed

Lin, Yuan; Wang, Luling; Zhang, Peibiao; Wang, Xin; Chen, Xuesi; Jing, Xiabin; Su, Zhaohui

2006-03-01

Poly(L-lactide) (PLLA) surface was modified via aminolysis by poly(allylamine hydrochloride) (PAH) at high pH and subsequent electrostatic self-assembly of poly(sodium styrenesulfonate) (PSS) and PAH, and the process was monitored by X-ray photoelectron spectroscopy (XPS) and contact angle measurement. These modified PLLAs were then used as charged substrates for further incorporation of gelatin to improve their cytocompatibility. The amphoteric nature of the gelatin was exploited and the gelatin was adsorbed to the negatively charged PLLA/PSS and positively charged PLLA/PAH at pH=3.4 and 7.4, respectively. XPS and water contact angle data indicated that the gelatin adsorption at pH=3.4 resulted in much higher surface coverage by gelatin than at pH=7.4. All the modified PLLA surfaces became more hydrophilic than the virgin PLLA. Chondrocyte culture was used to test the cell attachment, cell morphology and cell viability on the modified PLLA substrates. The results showed that the PAH and PSS modified PLLA exhibited better cytocompatibility than virgin PLLA, and the incorporation of the gelatin on these modified PLLA substrates further improved their cytocompatibility, with the PLLA/PSS substrate treated with the gelatin at pH=3.4 being the best, exceeding the chondrocyte compatibility of the tissue culture polystyrene.

Bovine serum albumin nanoparticles as controlled release carrier for local drug delivery to the inner ear

NASA Astrophysics Data System (ADS)

Yu, Zhan; Yu, Min; Zhang, Zhibao; Hong, Ge; Xiong, Qingqing

2014-07-01

Nanoparticles have attracted increasing attention for local drug delivery to the inner ear recently. Bovine serum albumin (BSA) nanoparticles were prepared by desolvation method followed by glutaraldehyde fixation or heat denaturation. The nanoparticles were spherical in shape with an average diameter of 492 nm. The heat-denatured nanoparticles had good cytocompatibility. The nanoparticles could adhere on and penetrate through the round window membrane of guinea pigs. The nanoparticles were analyzed as drug carriers to investigate the loading capacity and release behaviors. Rhodamine B was used as a model drug in this paper. Rhodamine B-loaded nanoparticles showed a controlled release profile and could be deposited on the osseous spiral lamina. We considered that the bovine serum albumin nanoparticles may have potential applications in the field of local drug delivery in the treatment of inner ear disorders.

Influence of silicon doping of titanium nickelide near-surface layers on alloy cytocompatibility

NASA Astrophysics Data System (ADS)

Lotkov, A. I.; Matveev, A. L.; Artemyeva, L. V.; Meysner, S. N.; Matveeva, V. A.; Kudryashov, A. N.

2017-12-01

The cytocompatibility of titanium nickelide (TiNi) with near-surface layers doped with silicon ions was studied on mesenchymal stem cells of rat bone marrow cultivated in vitro. The cytotoxic effect of eluted components of material on the mesenchymal stem cells was determined using a RTCA iCELLigence cellular analyzer. The proliferative activity of mesenchymal stem cells cultivated in the presence or on the surfaces of titanium nickelide samples was estimated from the cell mitochondrial respiration rate in MTT tests using [2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-(2, 4-disulfophenyl)-2H-tetrazolium] tetrazolium salt. It is shown that ion plasma modification of near-surface layers of titanium nickelide with silicon improves the cytocompatibility of the alloy.

Silver nanoparticles decorated lipase-sensitive polyurethane micelles for on-demand release of silver nanoparticles.

PubMed

Su, Yuling; Zhao, Lili; Meng, Fancui; Wang, Quanxin; Yao, Yongchao; Luo, Jianbin

2017-04-01

In order to improve the antibacterial activities while decrease the cytotoxity of silver nanoparticles, we prepared a novel nanocomposites composed of silver nanoparticles decorated lipase-sensitive polyurethane micelles (PUM-Ag) with MPEG brush on the surface. The nanocomposite was characterized by UV-vis, TEM and DLS. UV-vis and TEM demonstrated the formation of silver nanoparticles on PU micelles and the nanoassembly remained intact without the presence of lipase. The silver nanoparticles were protected by the polymer matrix and PEG brush which show good cytocompatibility to HUVEC cells and low hemolysis. Moreover, at the presence of lipase, the polymer matrix of nanocomposites is subject to degradation and the small silver nanoparticles were released as is shown by DLS and TEM. The MIC and MBC studies showed an enhanced toxicity of the nanocomposites to both gram negative and gram positive bacteria, i.e. E. coli and S. aureus, as the result of the degradation of polymer matrix by bacterial lipase. Therefore, the nanocomposites are biocompatible to mammalian cells cells which can also lead to activated smaller silver nanoparticles release at the presence of bacteria and subsequently enhanced inhibition of bacteria growth. The satisfactory selectivity for bacteria compared to HUVEC and RBCs make PUM-Ag a promising antibacterial nanomedicine in biomedical field. Copyright © 2017 Elsevier B.V. All rights reserved.

Bioactive Polymeric Nanoparticles for Periodontal Therapy

PubMed Central

Alfonso-Rodríguez, Camilo Andrés; Medina-Castillo, Antonio L.; Alaminos, Miguel; Toledano, Manuel

2016-01-01

Aims to design calcium and zinc-loaded bioactive and cytocompatible nanoparticles for the treatment of periodontal disease. Methods PolymP-nActive nanoparticles were zinc or calcium loaded. Biomimetic calcium phosphate precipitation on polymeric particles was assessed after 7 days immersion in simulated body fluid, by scanning electron microscopy attached to an energy dispersive analysis system. Amorphous mineral deposition was probed by X-ray diffraction. Cell viability analysis was performed using oral mucosa fibroblasts by: 1) quantifying the liberated deoxyribonucleic acid from dead cells, 2) detecting the amount of lactate dehydrogenase enzyme released by cells with damaged membranes, and 3) by examining the cytoplasmic esterase function and cell membranes integrity with a fluorescence-based method using the Live/Dead commercial kit. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests. Results Precipitation of calcium and phosphate on the nanoparticles surfaces was observed in calcium-loaded nanoparticles. Non-loaded nanoparticles were found to be non-toxic in all the assays, calcium and zinc-loaded particles presented a dose dependent but very low cytotoxic effect. Conclusions The ability of calcium-loaded nanoparticles to promote precipitation of calcium phosphate deposits, together with their observed non-toxicity may offer new strategies for periodontal disease treatment. PMID:27820866

Novel strontium-doped bioactive glass nanoparticles enhance proliferation and osteogenic differentiation of human bone marrow stromal cells

NASA Astrophysics Data System (ADS)

Strobel, L. A.; Hild, N.; Mohn, D.; Stark, W. J.; Hoppe, A.; Gbureck, U.; Horch, R. E.; Kneser, U.; Boccaccini, A. R.

2013-07-01

The present study investigates a new family of bioactive glass nanoparticles with and without Sr-doping focusing on the influence of the nanoparticles on human bone marrow stromal cells (hBMSCs) in vitro. The bioactive glass nanoparticles were fabricated by flame spray synthesis and a particle diameter of 30-35 nm was achieved. Glass nanoparticles were undoped (BG 13-93-0Sr) or doped with 5 wt% strontium (Sr) (BG 13-93-5Sr) and used at concentrations of 10 and 100 μg/cm² (particles per culture plate area), respectively. Cells were cultured for 14 days after which the samples were analysed regarding metabolic activity and expression of various bone-specific genes. Cell growth and morphology indicated the high cytocompatibility of the nanoparticulate bioactive glass. The presence of the nanoparticles enhanced cell growth compared to the plain polystyrene control group. At a concentration of 100 μg/cm², Sr-doped particles led to significantly enhanced gene expression of osteocalcin, collagen type 1 and vascular endothelial growth factor. Thus, Sr-doped nanoparticles showing a dose-dependent increase of osteogenic differentiation in hBMSCs are a promising biomaterial for bone regeneration purposes.

Mesoporous silica fillers and resin composition effect on dental composites cytocompatibility.

PubMed

Attik, Nina; Hallay, Franck; Bois, Laurence; Brioude, Arnaud; Grosgogeat, Brigitte; Colon, Pierre

2017-02-01

Many new dental composites containing mesoporous silica fillers have been developed to improve rheological properties and enhance the resin-filler interface. To investigate the correlation between the cytocompatibility of several dental composites and their composition; two aspects have been considered: presence of bisphenol A (BPA)-glycidyl methacrylate (Bis-GMA) or triethyleneglycol-dimethacrylate (TEGDMA) among the resin monomers and presence of porous particles among the filler blends. Five commercial composites with different resin matrices and mineral fillers were compared to four experimental composites designed without any BPA-based monomers or TEGDMA. Porous fillers, with or without silanation, were added in some of the experimental composites. Two reference resin matrices were also selected. Cytocompatibility with cultured primary human gingival fibroblasts was assessed by confocal laser scanning microscopy with time-lapse imaging. Fourier transform infrared spectroscopy was used to control monomer conversion rate. Conversion rates of the experimental composites ranged from 57% to 71%, a comparable ratio for dental composites. Experimental samples were better tolerated than tested commercial samples not containing TEGDMA and significantly better than those containing TEGDMA. Experimental composites with porous fillers exhibited good cytocompatibility, especially when surfaces were silanated. Cytotoxicity was associated with resin amount and especially resin nature. Composites containing porous fillers might behave as if the resin trapped into pores has no effect on toxicity. The cytotoxicity of composites with and without BPA derivatives was mainly attributed to the release of residual TEGDMA rather than the BPA derivatives. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Degradation, bioactivity, and cytocompatibility of diopside, akermanite, and bredigite ceramics.

PubMed

Wu, Chengtie; Chang, Jiang

2007-10-01

The aim of this study was to investigate the effect of three bioceramics in the CaO-SiO(2)-MgO systems with different composition on the in vitro degradation, bioactivity, and cytocompatibility. The degradation was evaluated through the activation energy of Si ion release from ceramics and the weight loss of the ceramics in Tris-HCl buffers. The in vitro bioactivity of the ceramics was investigated by analysis of apatite-formation ability in the simulated body fluid (SBF). The cytocompatibility was evaluated through osteoblast morphology and proliferation. The results showed that the activation energy of Si ion release increased and the degradation decreased from bredigite to diopside ceramics with the increase of Mg content, and the apatite-formation ability in SBF decreased. The Ca, Si, and Mg containing ionic products from three ceramics could stimulate cell proliferation at lower concentration, and inhibit cell proliferation with the increase of ion concentrations. Furthermore, osteoblasts could adhere, spread, and proliferate on three ceramic disks, and cell proliferation on diopside was more obvious than that on other two ceramic disks.

Non-hazardous anticancerous and antibacterial colloidal 'green' silver nanoparticles.

PubMed

Barua, Shaswat; Konwarh, Rocktotpal; Bhattacharya, Satya Sundar; Das, Pallabi; Devi, K Sanjana P; Maiti, Tapas K; Mandal, Manabendra; Karak, Niranjan

2013-05-01

Poly(ethylene glycol) stabilized colloidal silver nanoparticles were prepared using the reductive potency of the aqueous extract of Thuja occidentalis leaves under ambient conditions. The nanoparticles were well dispersed within a narrow size spectrum (7-14 nm) and displayed characteristic surface plasmon resonance peak at around 420 nm and Bragg's reflection planes of fcc structure. MTT assay revealed the dose-dependent cytocompatibility and toxicity of the nanoparticles with the L929 normal cell line. On the other hand, the antiproliferative action of the nanoparticles was evaluated on HeLa cell (cancerous cells) line. Fluorescence and phase contrast microscopic imaging indicated the appearance of multinucleate stages with aggregation and nuclear membrane disruption of the HeLa cells post treatment with the nanoparticles. The interaction at the prokaryotic level was also assessed via differential antibacterial efficacy against Staphylococcus aureus (MTCC 3160) and Escherichia coli (MTCC 40). Under these perspectives, it is also necessary to observe the environmental impact of the prepared silver nanoparticles. Hence, the dose dependent toxicity of silver nanoparticles was evaluated upon the earthworm species Eisenia fetida. Neither the survival nor the reproduction was affected by the addition of silver nanoparticles up to 1000 ppm. Thus these 'green' silver nanoparticles have promising potential as future materials. Copyright © 2012 Elsevier B.V. All rights reserved.

Cytocompatible and water stable ultrafine protein fibers for tissue engineering

NASA Astrophysics Data System (ADS)

Jiang, Qiuran

This dissertation proposal focuses on the development of cytocompatible and water stable protein ultrafine fibers for tissue engineering. The protein-based ultrafine fibers have the potential to be used for biomedicine, due to their biocompatibility, biodegradability, similarity to natural extracellular matrix (ECM) in physical structure and chemical composition, and superior adsorption properties due to their high surface to volume ratio. However, the current technologies to produce the protein-based ultrafine fibers for biomedical applications still have several problems. For instance, the current electrospinning and phase separation technologies generate scaffolds composed of densely compacted ultrafine fibers, and cells can spread just on the surface of the fiber bulk, and hardly penetrate into the inner sections of scaffolds. Thus, these scaffolds can merely emulate the ECM as a two dimensional basement membrane, but are difficult to mimic the three dimensional ECM stroma. Moreover, the protein-based ultrafine fibers do not possess sufficient water stability and strength for biomedical applications, and need modifications such as crosslinking. However, current crosslinking methods are either high in toxicity or low in crosslinking efficiency. To solve the problems mentioned above, zein, collagen, and gelatin were selected as the raw materials to represent plant proteins, animal proteins, and denatured proteins in this dissertation. A benign solvent system was developed specifically for the fabrication of collagen ultrafine fibers. In addition, the gelatin scaffolds with a loose fibrous structure, high cell-accessibility and cell viability were produced by a novel ultralow concentration phase separation method aiming to simulate the structure of three dimensional (3D) ECM stroma. Non-toxic crosslinking methods using citric acid as the crosslinker were also developed for electrospun or phase separated scaffolds from these three proteins, and proved to be

Cytocompatibility of polyethylene grafted with triethylenetetramine functionalized carbon nanoparticles

NASA Astrophysics Data System (ADS)

Žáková, Pavlína; Slepičková Kasálková, Nikola; Slepička, Petr; Kolská, Zdeňka; Karpíšková, Jana; Stibor, Ivan; Švorčík, Václav

2017-11-01

Various carbon nanostructures are widely researched as scaffolds for tissue engineering. We evaluated the surface properties and cell-substrate interactions of carbon nanoparticles functionalized with triethylenetetramine (CNPs) grafted polymer film. Two forms of polyethylene (HDPE, LDPE) were treated in an inert argon plasma discharge and, subsequently, grafted with CNPs. The surface properties were studied using multiple methods, including Raman spectroscopy, goniometry, atomic force microscopy, X-ray photoelectron spectroscopy and electrokinetic analysis. Cell-substrate interactions were determined in vitro by studying adhesion, proliferation and viability of vascular smooth muscle cells (VSMCs) from the aorta of a rat. Cell-substrate interactions on pristine and modified substrates were compared to standard tissue culture polystyrene. Our results show that CNPs affect surface morphology and wettability and therefore adhesion, proliferation and viability of cultured muscle cells.

Improvement of in vitro corrosion and cytocompatibility of biodegradable Fe surface modified by Zn ion implantation

NASA Astrophysics Data System (ADS)

Wang, Henan; Zheng, Yang; Li, Yan; Jiang, Chengbao

2017-05-01

Pure Fe was surface-modified by Zn ion implantation to improve the biodegradable behavior and cytocompatibility. Surface topography, chemical composition, corrosion resistance and cytocompatibility were investigated. Atomic force microscopy, auger electron spectroscopy and X-ray photoelectron spectroscopy results showed that Zn was implanted into the surface of pure Fe in the depth of 40-60 nm and Fe2O3/ZnO oxides were formed on the outmost surface. Electrochemical measurements and immersion tests revealed an improved degradable behavior for the Zn-implanted Fe samples. An approximately 12% reduction in the corrosion potential (Ecorr) and a 10-fold increase in the corrosion current density (icorr) were obtained after Zn ion implantation with a moderate incident ion dose, which was attributed to the enhanced pitting corrosion. The surface free energy of pure Fe was decreased by Zn ion implantation. The results of direct cell culture indicated that the short-term (4 h) cytocompatibility of MC3T3-E1 cells was promoted by the implanted Zn on the surface.

Polyurethane/poly(vinyl alcohol) hydrogel coating improves the cytocompatibility of neural electrodes

PubMed Central

Li, Mei; Zhou, Hai-han; Li, Tao; Li, Cheng-yan; Xia, Zhong-yuan; Duan, Yanwen Y.

2015-01-01

Neural electrodes, the core component of neural prostheses, are usually encapsulated in polydimethylsiloxane (PDMS). However, PDMS can generate a tissue response after implantation. Based on the physicochemical properties and excellent biocompatibility of polyurethane (PU) and poly(vinyl alcohol) (PVA) when used as coating materials, we synthesized PU/PVA hydrogel coatings and coated the surface of PDMS using plasma treatment, and the cytocompatibility to rat pheochromocytoma (PC12) cells was assessed. Protein adsorption tests indicated that the amount of protein adsorption onto the PDMS substrate was reduced by 92% after coating with the hydrogel. Moreover, the PC12 cells on the PU/PVA-coated PDMS showed higher cell density and longer and more numerous neurites than those on the uncoated PDMS. These results indicate that the PU/PVA hydrogel is cytocompatible and a promising coating material for neural electrodes to improve their biocompatibility. PMID:26889197

[The preparation of a new hydroxyapatite and the study on its cytocompatibility].

PubMed

Tao, Kai; Mao, Tianqiu; Chen, Fulin; Liu, Xiaoyan

2006-08-01

The cuttlebones, harvested from cuttles, undergo the chemical reaction in high temperature and high pressure for a certain time. The products are qualitatively analysed, and spacial structure observation and cytocompatibility are tested. The results show that the chemical component of the cuttlebone is CaCO3 and the crystal type is aragonite. Cuttlebones undergo a hydro-thermal reaction, and thus transform into hydroxyapatite-that is, the cuttlebone-transformed hydroxyapatite(CBHA). The CBHA materials have the interconnected microporous network structures. Under the high magnification, CBHAs appear to have many micro-spheres, thus construct a new self-assembled nano-material system. The marrow stromal osteoblasts can adhere to and proliferate well on the surface of the CBHAs. These results show that CBHAs have good biocompatibility. Therefore, it can be a potential candidate scaffold for bone tissue engineering.

Amidase encapsulated O-carboxymethyl chitosan nanoparticles for vaccine delivery.

PubMed

Smitha, K T; Sreelakshmi, M; Nisha, N; Jayakumar, R; Biswas, Raja

2014-02-01

This work reports the development of amidase encapsulated O-carboxymethyl chitosan nanoparticles (Ami-O-CMC NPs) of 300±50 nm size by ionic cross-linking method. The prepared Ami-O-CMC NPs had an encapsulation efficiency of 55.39%. Haemolysis assay and cytotoxicity studies proved the hemocompatibility and cytocompatibility of the prepared NPs. The sustained release of Ami from the NPs is expected to prolong its immunogenicity and in turn lead to development of better protective immunity against Staphylococcus aureus infections. Copyright © 2013 Elsevier B.V. All rights reserved.

In Vitro Corrosion and Cytocompatibility of ZK60 Magnesium Alloy Coated with Hydroxyapatite by a Simple Chemical Conversion Process for Orthopedic Applications

PubMed Central

Wang, Bing; Huang, Ping; Ou, Caiwen; Li, Kaikai; Yan, Biao; Lu, Wei

2013-01-01

Magnesium and its alloys—a new class of degradable metallic biomaterials—are being increasingly investigated as a promising alternative for medical implant and device applications due to their advantageous mechanical and biological properties. However, the high corrosion rate in physiological environments prevents the clinical application of Mg-based materials. Therefore, the objective of this study was to develop a hydroxyapatite (HA) coating on ZK60 magnesium alloy substrates to mediate the rapid degradation of Mg while improving its cytocompatibility for orthopedic applications. A simple chemical conversion process was applied to prepare HA coating on ZK60 magnesium alloy. Surface morphology, elemental compositions, and crystal structures were characterized using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction, respectively. The corrosion properties of samples were investigated by immersion test and electrochemical test. Murine fibroblast L-929 cells were harvested and cultured with coated and non-coated ZK60 samples to determine cytocompatibility. The degradation results suggested that the HA coatings decreased the degradation of ZK60 alloy. No significant deterioration in compression strength was observed for all the uncoated and coated samples after 2 and 4 weeks’ immersion in simulated body fluid (SBF). Cytotoxicity test indicated that the coatings, especially HA coating, improved cytocompatibility of ZK60 alloy for L929 cells. PMID:24300096

Mechanical properties and cytocompatibility of oxygen-modified β-type Ti-Cr alloys for spinal fixation devices.

PubMed

Liu, Huihong; Niinomi, Mitsuo; Nakai, Masaaki; Cho, Ken; Narita, Kengo; Şen, Mustafa; Shiku, Hitoshi; Matsue, Tomokazu

2015-01-01

In this study, various amounts of oxygen were added to Ti-10Cr (mass%) alloys. It is expected that a large changeable Young's modulus, caused by a deformation-induced ω-phase transformation, can be achieved in Ti-10Cr-O alloys by the appropriate oxygen addition. This "changeable Young's modulus" property can satisfy the otherwise conflicting requirements for use in spinal implant rods: high and low moduli are preferred by surgeons and patients, respectively. The influence of oxygen on the microstructures and mechanical properties of the alloys was examined, as well as the bending springback and cytocompatibility of the optimized alloy. Among the Ti-10Cr-O alloys, Ti-10Cr-0.2O (mass%) alloy shows the largest changeable Young's modulus following cold rolling for a constant reduction ratio. This is the result of two competing factors: increased apparent β-lattice stability and decreased amounts of athermal ω phase, both of which are caused by oxygen addition. The most favorable balance of these factors for the deformation-induced ω-phase transformation occurred at an oxygen concentration of 0.2mass%. Ti-10Cr-0.2O alloy not only exhibits high tensile strength and acceptable elongation, but also possesses a good combination of high bending strength, acceptable bending springback and great cytocompatibility. Therefore, Ti-10Cr-0.2O alloy is a potential material for use in spinal fixture devices. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Corrosion behavior and cytocompatibility of fluoride-incorporated plasma electrolytic oxidation coating on biodegradable AZ31 alloy

PubMed Central

Tian, Peng; Peng, Feng; Wang, Donghui; Liu, Xuanyong

2017-01-01

Fluoride-incorporated plasma electrolytic oxidation (PEO) coating was fabricated on biodegradable AZ31 alloy. The surface morphologies and phases were investigated by scanning electron microscopy and X-ray diffraction. The effect of fluoride incorporation in coatings on corrosion behaviour was investigated in simulated body fluid and in vitro cytocompatibility of the coatings was also studied by evaluating cytotoxicity, adhesion, proliferation and live–dead stain of osteoblast cells (MC3T3-E1). Furthermore, the corrosion morphologies in vivo were examined. The results showed that the fluoride could be incorporated into the coating to form MgF2 phase. In vitro and in vivo degradation tests revealed that the corrosion resistance of the coating could be improved by the incorporation of fluoride, which may attribute to the chemical stability of MgF2 phase. Moreover, good cytocompatibility of fluoride-incorporated coating was confirmed with no obvious cytotoxicity, enhanced cell adhesion and proliferation. However, when the fluoride content was high, a slight inhibition of cell growth was observed. The results indicate that although fluoride incorporation can enhance the corrosion resistance of the coatings, thus resulting a more suitable environment for cells, the high content of fluoride in the coating also kill cells ascribed to the high released of fluorine. If the content of fluoride is well controlled, the PEO coating with MgF2 phase is a promising surface modification of Mg alloys. PMID:28149524

Corrosion behavior and cytocompatibility of fluoride-incorporated plasma electrolytic oxidation coating on biodegradable AZ31 alloy.

PubMed

Tian, Peng; Peng, Feng; Wang, Donghui; Liu, Xuanyong

2017-02-01

Fluoride-incorporated plasma electrolytic oxidation (PEO) coating was fabricated on biodegradable AZ31 alloy. The surface morphologies and phases were investigated by scanning electron microscopy and X-ray diffraction. The effect of fluoride incorporation in coatings on corrosion behaviour was investigated in simulated body fluid and in vitro cytocompatibility of the coatings was also studied by evaluating cytotoxicity, adhesion, proliferation and live-dead stain of osteoblast cells (MC3T3-E1). Furthermore, the corrosion morphologies in vivo were examined. The results showed that the fluoride could be incorporated into the coating to form MgF 2 phase. In vitro and in vivo degradation tests revealed that the corrosion resistance of the coating could be improved by the incorporation of fluoride, which may attribute to the chemical stability of MgF 2 phase. Moreover, good cytocompatibility of fluoride-incorporated coating was confirmed with no obvious cytotoxicity, enhanced cell adhesion and proliferation. However, when the fluoride content was high, a slight inhibition of cell growth was observed. The results indicate that although fluoride incorporation can enhance the corrosion resistance of the coatings, thus resulting a more suitable environment for cells, the high content of fluoride in the coating also kill cells ascribed to the high released of fluorine. If the content of fluoride is well controlled, the PEO coating with MgF 2 phase is a promising surface modification of Mg alloys.

In Vitro Cytocompatibility of One- and Two-Dimensional Nanostructure-Reinforced Biodegradable Polymeric Nanocomposites

PubMed Central

Farshid, Behzad; Lalwani, Gaurav; Sitharaman, Balaji

2015-01-01

This study investigates the in vitro cytocompatibility of one- and two-dimensional (1-D and 2-D) carbon and inorganic nanomaterial reinforced polymeric nanocomposites fabricated using biodegradable polymer poly (propylene fumarate), crosslinking agent N-vinyl pyrrolidone (NVP) and following nanomaterials: single- and multi- walled carbon nanotubes, single- and multi- walled graphene oxide nanoribbons, graphene oxide nanoplatelets, molybdenum disulfide nanoplatelets, or tungsten disulfide nanotubes dispersed between 0.02–0.2 wt% concentrations in the polymer. The extraction media of unreacted components, crosslinked nanocomposites and their degradation products between 1X-100X dilutions were examined for effects on viability and attachment employing two cell lines: NIH3T3 fibroblasts and MC3T3 pre-osteoblasts. The extraction media of unreacted PPF/NVP elicited acute dose-dependent cytotoxicity attributed to leaching of unreacted components into cell culture media. However, extraction media of crosslinked nanocomposites showed no dose dependent adverse effects. Further, all crosslinked nanocomposites showed high viability (78–100%), high cellular attachment (40–55%), and spreading that was confirmed by confocal and scanning electron microscopy. Degradation products of nanocomposites showed a mild dose-dependent cytotoxicity possibly due to acidic degradation components of PPF. In general, compared to PPF control, none of the nanocomposites showed significant differences in cellular response to the unreacted components, crosslinked nanocomposites and their degradation products. The initial minor cytotoxic response and lower cell attachment numbers were observed only for a few nanocomposite groups; these effects were absent at later time points for all PPF nanocomposites. The favorable cytocompatibility results for all the nanocomposites opens avenues for in vivo safety and efficacy studies for bone tissue engineering applications. PMID:25367032

[Cytocompatibility of collagen membranes with bladder transitional cells of rabbit in vitro].

PubMed

Sun, Daodong; Song, Bo; Sun, Danning

2004-05-01

To evaluate the cytocompatibility of collagen membranes with transitional cells of rabbit in vitro and to discuss the possibility of the collagen membranes as urologic tissue engineering scaffolds. Primary cultured transitional cells isolated from New Zealand rabbits were implanted on collagen membranes at 1 x 10(5) cells/cm2. The changes of cell adhering were observed by inverted microscope and scanning electron microscope 2, 12 and 24 hours later. The experiment was divided into 4 groups: non-cell group (black control) culture medium group (negative control), extract medium from Polyvinyl chloride group(positive control) and extract medium from collagen membranes group(experimental group). The cells of generations 2 to 4 were implanted in 96-hole-plank at 1 x 10(4) cells every hole. And every group had 5 holes. Then absorption coefficient were detected at the wave length of 490 nm by MTT assay. Then the cytotoxicity and cytocompatibility were evaluated by comparison of the numbers of absorption coefficient. The bladder transitional cells began to adhere to the collagen membrane 2 hours after implanting, and the number of the adhered cells increased with time. The actual absorption coefficient of experimental groups was 0.590 +/- 0.024, 1.065 +/- 0.40 and 1.129 +/- 0.074 after 24, 72 and 120 hours. The actual absorption coefficient of negative control group was 0.639 +/- 0.068, 1.022 +/- 0.044 and 1.087 +/- 0.111. The actual absorption coefficient of positive control group was 0.302 +/- 0.029, 0.653 +/- 0.083 and 0.694 +/- 0.031. There was significant difference between the experimental group and positive control (P < 0.01), and no significant difference between the experimental group and negative control(P > 0.05). Collagen membrane has good cytocompatibility with transitional cells and no cytotoxicity. It can be used as scaffolds of urologic tissue engineering.

Improved Mechanical Compatibility and Cytocompatibility of Ta/Ti Double-Layered Composite Coating

NASA Astrophysics Data System (ADS)

Ding, Ding; Xie, Youtao; Li, Kai; Huang, Liping; Zheng, Xuebin

2017-08-01

In order to improve the mechanical compatibility and cytocompatibility of titanium implants, a composite coating with double layers composed of tantalum and titanium was designed and prepared using plasma spraying technology. In the composite coating, the upper tantalum layer provides a good biocompatibility, and the sublayer of titanium with a porous structure ensures the low elastic modulus. Results show that the fabricated composite coating exhibits a relatively low elastic modulus of 26.7 GPa, which is close to the elastic modulus of human cortical bone. In vitro cytocompatibility evaluation of the composite coating shows that the human bone marrow stromal cells exhibit enhanced adhesion and spreading performance on the double-layered composite coating in comparison with the single-layered titanium coating. In order to eliminate the misgivings of chemical stability of the composite coating in clinical application, electrochemical corrosion of the coating was examined. The results obtained revealed a very weak galvanic corrosion between the tantalum and titanium in the composite coating, which would ensure the safety of the coating in vivo.

Gold nanoparticles deposited on glass: physicochemical characterization and cytocompatibility

PubMed Central

2013-01-01

Properties of gold films sputtered under different conditions onto borosilicate glass substrate were studied. Mean thickness of sputtered gold film was measured by gravimetry, and film contact angle was determined by goniometry. Surface morphology was examined by atomic force microscopy, and electrical sheet resistance was determined by two-point technique. The samples were seeded with rat vascular smooth muscle cells, and their adhesion and proliferation were studied. Gold depositions lead to dramatical changes in the surface morphology and roughness in comparison to pristine substrate. For sputtered gold structures, the rapid decline of the sheet resistance appears on structures deposited for the times above 100 s. The thickness of deposited gold nanoparticles/layer is an increasing function of sputtering time and current. AFM images prove the creation of separated gold islands in the initial deposition phase and a continuous gold coverage for longer deposition times. Gold deposition has a positive effect on the proliferation of vascular smooth muscle cells. Largest number of cells was observed on sample sputtered with gold for 20 s and at the discharge current of 40 mA. This sample exhibits lowest contact angle, low relative roughness, and only mild increase of electrical conductivity. PMID:23705782

Novel genipin crosslinked atorvastatin loaded sericin nanoparticles for their enhanced antihyperlipidemic activity.

PubMed

Kanoujia, Jovita; Singh, Mahendra; Singh, Pooja; Saraf, Shubhini A

2016-12-01

The objective of this study was to demonstrate the therapeutic as well as biopolymer like characteristics of naturally occurring sericin protein for development of nanoparticulate system of atorvastatin (Atr) to improve therapeutic effect and to reduce toxicity. The sericin encapsulated atorvastatin nanoparticles (Seri-Atr NPs) were prepared by desolvation method utilizing genipin (Gn) as a natural and nontoxic crosslinker. The optimized NPs exhibited small particle size (166±0.30nm), high entrapment efficiency (91±0.69%) and uniform spherical shape with sustained release profile. Moreover, the results of pharmacokinetic studies indicated an increase in AUC0-∞ of NPs (1189.74±52.3hng/ml) compared with Atr (501.84±66hng/ml). The cellular uptake of NPs suggested an interaction of negatively charged particles with the cell surface and considerable reduction in systemic toxicity. Histopathology studies also demonstrated the therapeutic potential of sericin and cytocompatibility. Hence, genipin crosslinked sericin based nanoparticles represents a promising nanoplatform for improved therapeutic efficiency of Atr. Copyright © 2016 Elsevier B.V. All rights reserved.

Modulation, functionality, and cytocompatibility of three-dimensional printing materials made from chitosan-based polysaccharide composites.

PubMed

Wu, Chin-San

2016-12-01

The mechanical properties, cytocompatibility, and fabrication of three-dimensional (3D) printing strips of composite materials containing polylactide (PLA) and chitosan (CS) were evaluated. Maleic anhydride-grafted polylactide (PLA-g-MA) and CS were used to enhance the desired characteristics of these composites. The PLA-g-MA/CS materials exhibited better mechanical properties than the PLA/CS composites; this effect was attributed to a greater compatibility between the grafted polyester and CS. The water resistance of the PLA-g-MA/CS composites was greater than that of the PLA/CS composites; cytocompatibility evaluation with human foreskin fibroblasts (FBs) indicated that both materials were nontoxic. Moreover, CS enhanced the antibacterial activity properties of PLA-g-MA and PLA/CS composites. Copyright © 2016 Elsevier B.V. All rights reserved.

pH-Responsive Hydrogels with Dispersed Hydrophobic Nanoparticles for the Oral Delivery of Chemotherapeutics

PubMed Central

Schoener, Cody A.; Hutson, Heather N.; Peppas, Nicholas A.

2012-01-01

Amphiphilic polymer carriers were formed by polymerizing a hydrophilic, pH-responsive hydrogel composed of poly(methacrylic – grafted – ethylene glycol) (P(MAA-g-EG)) in the presence of hydrophobic PMMA nanoparticles. These polymer carriers were varied in PMMA nanoparticle content to elicit a variety of physiochemical properties which would preferentially load doxorubicin, a hydrophobic chemotherapeutic, and release doxorubicin locally in the colon for the treatment of colon cancers. Loading levels ranged from 49% to 64% and increased with increasing nanoparticle content. Doxorubicin loaded polymers were released in a physiological model where low pH was used to simulate the stomach and then stepped to more neutral conditions to simulate the upper small intestine. P(MAA-g-EG) containing nanoparticles were less mucoadhesive as determined using a tensile tester, polymer samples, and fresh porcine small intestine. The cytocompatibility of the polymer materials were assessed using cell lines representing the GI tract and colon cancer and were non-cytotoxic at varying concentrations and exposure times. PMID:23281185

Bioactive glass (type 45S5) nanoparticles: in vitro reactivity on nanoscale and biocompatibility

NASA Astrophysics Data System (ADS)

Mačković, M.; Hoppe, A.; Detsch, R.; Mohn, D.; Stark, W. J.; Spiecker, E.; Boccaccini, A. R.

2012-07-01

Bioactive glasses represent important biomaterials being investigated for the repair and reconstruction of diseased bone tissues, as they exhibit outstanding bonding properties to human bone. In this study, bioactive glass (type 45S5) nanoparticles (nBG) with a mean particle size in the range of 20-60 nm, synthesised by flame spray synthesis, are investigated in relation to in vitro bioreactivity in simulated body fluid (SBF) and response to osteoblast cells. The structure and kinetics of hydroxyapatite formation in SBF were investigated using transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR) revealing a very rapid transformation (after 1 day) of nBG to nanocrystalline bone-like carbonated HAp. Additionally, calcite is formed after 1 day of SBF immersion because of the high surface reactivity of the nBG particles. In the initial state, nBG particles were found to exhibit chain-like porous agglomerates of amorphous nature which are transformed on immersion in SBF into compact agglomerates covered by hydroxyapatite with a reduced size of the primary nanoparticles. In vitro studies revealed high cytocompatibility of nBG with human osteoblast cells, indicated through high lactatedehydrogenase (LDH) and mitochondrial activity as well as alkaline phosphatase activity. Hence, this study contributes to the understanding of the structure and bioactivity of bioactive glass (type 45S5) nanoparticles, providing insights to the phenomena occurring at the nanoscale after immersion in SBF. The results are relevant in relation to the understanding of the nanoparticles' bioreactivity required for applications in bone tissue engineering.

Effects of MgO modified β-TCP nanoparticles on the microstructure and properties of β-TCP/Mg-Zn-Zr composites.

PubMed

Zheng, H R; Li, Z; You, C; Liu, D B; Chen, M F

2017-03-01

The mechanical properties and corrosion resistance of magnesium alloy composites were improved by the addition of MgO surface modified tricalcium phosphate ceramic nanoparticles (m-β-TCP). Mg-3Zn-0.8Zr composites with unmodified (MZZT) and modified (MZZMT) nanoparticles were produced by high shear mixing technology. Effects of MgO m-β-TCP nanoparticles on the microstructure, mechanical properties, electrochemical corrosion properties and cytocompatibility of Mg-Zn-Zr/β-TCP composites were investigated. After hot extrusion deformation and dynamic recrystallization, the grain size of MZZMT was the half size of MZZT and the distribution of m-β-TCP particles in the matrix was more uniform than β-TCP particles. The yield tensile strength (YTS), ultimate tensile strength (UTS), and corrosion potential (Ecorr) of MZZMT were higher than MZZT; the corrosion current density (I corr ) of MZZMT was lower than MZZT. Cell proliferation of co-cultured MZZMT and MZZT composite samples were roughly the same and the cell number at each time point is higher for MZZMT than for MZZT samples.

Surface-independent antibacterial coating using silver nanoparticle-generating engineered mussel glue.

PubMed

Jo, Yun Kee; Seo, Jeong Hyun; Choi, Bong-Hyuk; Kim, Bum Jin; Shin, Hwa Hui; Hwang, Byeong Hee; Cha, Hyung Joon

2014-11-26

During implant surgeries, antibacterial agents are needed to prevent bacterial infections, which can cause the formation of biofilms between implanted materials and tissue. Mussel adhesive proteins (MAPs) derived from marine mussels are bioadhesives that show strong adhesion and coating ability on various surfaces even in wet environment. Here, we proposed a novel surface-independent antibacterial coating strategy based on the fusion of MAP to a silver-binding peptide, which can synthesize silver nanoparticles having broad antibacterial activity. This sticky recombinant fusion protein enabled the efficient coating on target surface and the easy generation of silver nanoparticles on the coated-surface under mild condition. The biosynthesized silver nanoparticles showed excellent antibacterial efficacy against both Gram-positive and Gram-negative bacteria and also revealed good cytocompatibility with mammalian cells. In this coating strategy, MAP-silver binding peptide fusion proteins provide hybrid environment incorporating inorganic silver nanoparticle and simultaneously mediate the interaction of silver nanoparticle with surroundings. Moreover, the silver nanoparticles were fully synthesized on various surfaces including metal, plastic, and glass by a simple, surface-independent coating manner, and they were also successfully synthesized on a nanofiber surface fabricated by electrospinning of the fusion protein. Thus, this facile surface-independent silver nanoparticle-generating antibacterial coating has great potential to be used for the prevention of bacterial infection in diverse biomedical fields.

Cytocompatibility, cytotoxicity and genotoxicity analysis of dental implants

NASA Astrophysics Data System (ADS)

Reigosa, M.; Labarta, V.; Molinari, G.; Bernales, D.

2007-11-01

Several types of materials are frequently used for dental prostheses in dental medicine. Different treatments with titanium are the most used. The aim of the present study was to analyze by means of cytotoxicity and cytocompatibility techniques the capacity of dental implants to integrate to the bone tissue. Cultures of UMR 106 cell line derived from an osteosarcoma were used for bioassays mainly because they show many of the properties of osteoblasts. Dental implant samples provided by B&W company were compared with others of recognized trademarks. The first ones contain ASTM titanium (8348 GR2) with acid printing. Cytotoxicity was analyzed by means of lysosome activity, using the neutral red technique and alkaline phosphatase enzyme activity. Cell variability was determined by means of the acridine ethidium-orange bromide technique. One-way ANOVA and Bonferroni and Duncan post-ANOVA tests were used for the statistical analysis. The assays did not show significant differences among the dental implants analyzed. Our findings show that the dental prostheses studied present high biocompatibility, quantified by the bioassays performed. The techniques employed revealed that they can be a useful tool for the analysis of other materials for dental medicine use.

Nanoparticle layer deposition for highly controlled multilayer formation based on high- coverage monolayers of nanoparticles

PubMed Central

Liu, Yue; Williams, Mackenzie G.; Miller, Timothy J.; Teplyakov, Andrew V.

2015-01-01

This paper establishes a strategy for chemical deposition of functionalized nanoparticles onto solid substrates in a layer-by-layer process based on self-limiting surface chemical reactions leading to complete monolayer formation within the multilayer system without any additional intermediate layers – nanoparticle layer deposition (NPLD). This approach is fundamentally different from previously established traditional layer-by-layer deposition techniques and is conceptually more similar to well-known atomic and molecular – layer deposition processes. The NPLD approach uses efficient chemical functionalization of the solid substrate material and complementary functionalization of nanoparticles to produce a nearly 100% coverage of these nanoparticles with the use of “click chemistry”. Following this initial deposition, a second complete monolayer of nanoparticles is deposited using a copper-catalyzed “click reaction” with the azide-terminated silica nanoparticles of a different size. This layer-by-layer growth is demonstrated to produce stable covalently-bound multilayers of nearly perfect structure over macroscopic solid substrates. The formation of stable covalent bonds is confirmed spectroscopically and the stability of the multilayers produced is tested by sonication in a variety of common solvents. The 1-, 2- and 3-layer structures are interrogated by electron microscopy and atomic force microscopy and the thickness of the multilayers formed is fully consistent with that expected for highly efficient monolayer formation with each cycle of growth. This approach can be extended to include a variety of materials deposited in a predesigned sequence on different substrates with a highly conformal filling. PMID:26726273

A high-throughput label-free nanoparticle analyser.

PubMed

Fraikin, Jean-Luc; Teesalu, Tambet; McKenney, Christopher M; Ruoslahti, Erkki; Cleland, Andrew N

2011-05-01

Synthetic nanoparticles and genetically modified viruses are used in a range of applications, but high-throughput analytical tools for the physical characterization of these objects are needed. Here we present a microfluidic analyser that detects individual nanoparticles and characterizes complex, unlabelled nanoparticle suspensions. We demonstrate the detection, concentration analysis and sizing of individual synthetic nanoparticles in a multicomponent mixture with sufficient throughput to analyse 500,000 particles per second. We also report the rapid size and titre analysis of unlabelled bacteriophage T7 in both salt solution and mouse blood plasma, using just ~1 × 10⁻⁶ l of analyte. Unexpectedly, in the native blood plasma we discover a large background of naturally occurring nanoparticles with a power-law size distribution. The high-throughput detection capability, scalable fabrication and simple electronics of this instrument make it well suited for diverse applications.

Reduced bacteria adhesion on octenidine loaded mesoporous silica nanoparticles coating on titanium substrates.

PubMed

Xu, Gaoqiang; Shen, Xinkun; Dai, Liangliang; Ran, Qichun; Ma, Pingping; Cai, Kaiyong

2017-01-01

Bacterial infection is one of the most severe postoperative complications leading to implantation failure. The early bacterial stage (4-6h) was proved to be the "decisive period" for long-term bacteria-related infection. Thus, to endow potential early antibacterial capacity for a titanium (Ti) based implant, an effective antiseptic agent of octenidine dihydrochloride (OCT) was effectively loaded on the mesoporous silica nanoparticles (MSNs)-incorporated titania coating which was fabricated by an electrophoretic-enhanced micro-arc oxidation technique. The surface characteristic of the coatings were characterized by various methods (SEM, AFM, XPS, XRD, etc.), and its corrosion resistance was also examined by the potentiodynamic polarization curves. The composite coating without OCT loading not only displayed good cytocompatibility but also exhibited certain anti-bacterial property. After loading with OCT, its antibacterial efficiency of the titanium substrates with composite coating was greatly enhanced without compromising their cytocompatibility. The study provides an approach for the fabrication of anti-bacterial Ti implant for potential orthopedic application. Copyright © 2016 Elsevier B.V. All rights reserved.

Regenerated collagen fibers with grooved surface texture: Physicochemical characterization and cytocompatibility.

PubMed

Wang, Xiang; Wu, Tong; Wang, Wei; Huang, Chen; Jin, Xiangyu

2016-01-01

A novel type of protein fibers, regenerated collagen fibers (RC) from cattle skin, was prepared through wet-spinning. Due to the combined effect of solvent exchange and subsequent drawing process, the fibers were found to have a grooved surface texture. The grooves provided not only ordered topographical cues, but also increased surface area. Protein content of the RC fibers was confirmed by Fourier Transform infrared spectroscopy (FTIR) and ninhydrin color reaction. The fibers could be readily fabricated into nonwovens or other textiles, owning to their comparable physical properties to other commercialized fibers. Cell growth behavior on RC nonwovens suggested both early adhesion and prompt proliferation. The high moisture regain, good processability, along with the excellent cytocompatibility indicated that the RC fibers and nonwovens developed in this study might offer a good candidate for biomedical and healthcare applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Cytocompatibility and cellular internalization mechanisms of SiC/SiO2 nanowires.

PubMed

Cacchioli, A; Ravanetti, F; Alinovi, R; Pinelli, S; Rossi, F; Negri, M; Bedogni, E; Campanini, M; Galetti, M; Goldoni, M; Lagonegro, P; Alfieri, R; Bigi, F; Salviati, G

2014-08-13

First evidence of in vitro cytocompatibility of SiC/SiO2 core-shell nanowires is reported. Different internalization mechanisms by adenocarcinomic alveolar basal epithelial cells, monocytic cell line derived from an acute monocytic leukemia, breast cancer cells, and normal human dermal fibroblasts are shown. The internalization occurs mainly for macropinocytosis and sporadically by direct penetration in all cell models considered, whereas it occurred for phagocytosis only in monocytic leukemia cells. The cytocompatibility of the nanowires is proved by the analysis of cell proliferation, cell cycle progression, and oxidative stress on the cells treated with NWs as compared to controls. Reactive oxygen species generation was detected as an early event that then quickly run out with a rapid decrease only in adenocarcinomic alveolar basal epithelial and human dermal fibroblasts cells. In all the cell lines, the intracellular presence of NWs induce the same molecular events but to a different extent: peroxidation of membrane lipids and oxidation of proteins. The NWs do not elicit either midterm (72 h) or long-term (10 days) cytotoxic activity leading to irreversible cellular damages or death. Our results are important in view of a possible use of SiC/SiO2 core-shell structures acting as biomolecule-delivery vectors or intracellular electrodes.

A theranostic nanoplatform: magneto-gold@fluorescence polymer nanoparticles for tumor targeting T1&T2-MRI/CT/NIR fluorescence imaging and induction of genuine autophagy mediated chemotherapy.

PubMed

Wang, Guannan; Qian, Kun; Mei, Xifan

2018-06-14

Multifunctional nanoparticles, bearing low toxicity and tumor-targeting properties, coupled with multifunctional diagnostic imaging and enhanced treatment efficacy, have drawn tremendous attention due to their enormous potential for medical applications. Herein, we report a new kind of biocompatible and tumor-targeting magneto-gold@fluorescent polymer nanoparticle (MGFs-LyP-1), which is based on ultra-small magneto-gold (Fe 3 O 4 -Au) nanoparticles and NIR emissive fluorescent polymers by a solvent-mediated method. This kind of nanoparticle could be taken up efficiently and simultaneously serve for in vivo tumor targeting T 1 &T 2 -MRI/CT/near infrared (NIR) fluorescence bioimaging. Furthermore, the nanoparticles exhibit small size, higher tumor targeting accumulation, excellent cytocompatibility for long-term tracking, and no disturbing cell proliferation and differentiation. Moreover, clear and convincing evidence proves that as-synthesized MGFs-LyP-1 could elicit genuine autophagy via inducing autophagosome formation, which offers a definite synergistic effect to enhance cancer therapy with doxorubicin (DOX) at a nontoxic concentration through enhancement of the autophagy flux. Meanwhile, the as-prepared nanoparticles could be rapidly cleared from mice without any obvious organ impairment. The results indeed reveal a promising prospect of an MGFs-LyP-1 contrast agent with low toxicity and high efficiency for promising application in biomedicine.

Fabrication and Cytocompatibility of In Situ Crosslinked Carbon Nanomaterial Films

PubMed Central

Patel, Sunny C.; Lalwani, Gaurav; Grover, Kartikey; Qin, Yi-Xian; Sitharaman, Balaji

2015-01-01

Assembly of carbon nanomaterials into two-dimensional (2D) coatings and films that harness their unique physiochemical properties may lead to high impact energy capture/storage, sensors, and biomedical applications. For potential biomedical applications, the suitability of current techniques such as chemical vapor deposition, spray and dip coating, and vacuum filtration, employed to fabricate macroscopic 2D all carbon coatings or films still requires thorough examination. Each of these methods presents challenges with regards to scalability, suitability for a large variety of substrates, mechanical stability of coatings or films, or biocompatibility. Herein we report a coating process that allow for rapid, in situ chemical crosslinking of multi-walled carbon nanotubes (MWCNTs) into macroscopic all carbon coatings. The resultant coatings were found to be continuous, electrically conductive, significantly more robust, and cytocompatible to human adipose derived stem cells. The results lay groundwork for 3D layer-on-layer nanomaterial assemblies (including various forms of graphene) and also opens avenues to further explore the potential of MWCNT films as a novel class of nano-fibrous mats for tissue engineering and regenerative medicine. PMID:26018775

Optimized in vitro procedure for assessing the cytocompatibility of magnesium-based biomaterials.

PubMed

Jung, Ole; Smeets, Ralf; Porchetta, Dario; Kopp, Alexander; Ptock, Christoph; Müller, Ute; Heiland, Max; Schwade, Max; Behr, Björn; Kröger, Nadja; Kluwe, Lan; Hanken, Henning; Hartjen, Philip

2015-09-01

Magnesium (Mg) is a promising biomaterial for degradable implant applications that has been extensively studied in vitro and in vivo in recent years. In this study, we developed a procedure that allows an optimized and uniform in vitro assessment of the cytocompatibility of Mg-based materials while respecting the standard protocol DIN EN ISO 10993-5:2009. The mouse fibroblast line L-929 was chosen as the preferred assay cell line and MEM supplemented with 10% FCS, penicillin/streptomycin and 4mM l-glutamine as the favored assay medium. The procedure consists of (1) an indirect assessment of effects of soluble Mg corrosion products in material extracts and (2) a direct assessment of the surface compatibility in terms of cell attachment and cytotoxicity originating from active corrosion processes. The indirect assessment allows the quantification of cell-proliferation (BrdU-assay), viability (XTT-assay) as well as cytotoxicity (LDH-assay) of the mouse fibroblasts incubated with material extracts. Direct assessment visualizes cells attached to the test materials by means of live-dead staining. The colorimetric assays and the visual evaluation complement each other and the combination of both provides an optimized and simple procedure for assessing the cytocompatibility of Mg-based biomaterials in vitro. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

In vitro corrosion and cytocompatibility properties of nano-whisker hydroxyapatite coating on magnesium alloy for bone tissue engineering applications.

PubMed

Yang, Huawei; Yan, Xueyu; Ling, Min; Xiong, Zuquan; Ou, Caiwen; Lu, Wei

2015-03-17

We report here the successful fabrication of nano-whisker hydroxyapatite (nHA) coatings on Mg alloy by using a simple one-step hydrothermal process in aqueous solution. The nHA coating shows uniform structure and high crystallinity. Results indicate that nHA coating is promising for improving the in vitro corrosion and cytocompatibility properties of Mg-based implants and devices for bone tissue engineering. In addition, the simple hydrothermal deposition method used in the current study is also applicable to substrates with complex shapes or surface geometries.

Influence of Pre-Freezing Temperature on the Corneal Endothelial Cytocompatibility and Cell Delivery Performance of Porous Hyaluronic Acid Hydrogel Carriers.

PubMed

Lai, Jui-Yang

2015-08-11

The development of porous hyaluronic acid (HA) hydrogels for corneal endothelial tissue engineering is attractive because they can be used as functional cell delivery carriers to help in the reconstruction of damaged areas. The purpose of this study was to investigate the corneal endothelial cytocompatibility and cell delivery performance of porous HA hydrogel biomaterials fabricated at different pre-freezing temperatures. As compared to their counterparts prepared at -80 °C, the HA samples fabricated at higher pre-freezing temperature (i.e., 0 °C) exhibited a larger pore size and higher porosity, thereby leading to lower resistance to glucose permeation. Live/dead assays and gene expression analyses showed that the restricted porous structure of HA carriers decreases the viability and ionic pump function of cultured corneal endothelial cells (CECs). The results also indicated that the porous hydrogel biomaterials fabricated at high pre-freezing temperature seem to be more compatible with rabbit CECs. In an animal model of corneal endothelial dysfunction, the wounded rabbit corneas receiving bioengineered CEC sheets and restricted porous-structured HA carriers demonstrated poor tissue reconstruction. The therapeutic efficacy of cell sheet transplants can be improved by using carrier materials prepared at high pre-freezing temperature. Our findings suggest that the cryogenic operation temperature-mediated pore microstructure of HA carriers plays an important role in corneal endothelial cytocompatibility and cell delivery performance.

Adhesion, Vitality and Osteogenic Differentiation Capacity of Adipose Derived Stem Cells Seeded on Nitinol Nanoparticle Coatings

PubMed Central

Strauß, Sarah; Neumeister, Anne; Barcikowski, Stephan; Kracht, Dietmar; Kuhbier, Jörn W.; Radtke, Christine; Reimers, Kerstin; Vogt, Peter M.

2013-01-01

Autologous cells can be used for a bioactivation of osteoimplants to enhance osseointegration. In this regard, adipose derived stem cells (ASCs) offer interesting perspectives in implantology because they are fast and easy to isolate. However, not all materials licensed for bone implants are equally suited for cell adhesion. Surface modifications are under investigation to promote cytocompatibility and cell growth. The presented study focused on influences of a Nitinol-nanoparticle coating on ASCs. Possible toxic effects as well as influences on the osteogenic differentiation potential of ASCs were evaluated by viability assays, scanning electron microscopy, immunofluorescence and alizarin red staining. It was previously shown that Nitinol-nanoparticles exert no cell toxic effects to ASCs either in soluble form or as surface coating. Here we could demonstrate that a Nitinol-nanoparticle surface coating enhances cell adherence and growth on Nitinol-surfaces. No negative influence on the osteogenic differentiation was observed. Nitinol-nanoparticle coatings offer new possibilities in implantology research regarding bioactivation by autologous ASCs, respectively enhancement of surface attraction to cells. PMID:23308190

In vitro degradation behavior and cytocompatibility of biodegradable AZ31 alloy with PEO/HT composite coating.

PubMed

Tian, Peng; Liu, Xuanyong; Ding, Chuanxian

2015-04-01

Biodegradable magnesium-based implants have attracted much attention recently in orthopedic applications because of their good mechanical properties and biocompatibility. However, their rapid degradation in vivo will not only reduce their mechanical strength, but also induce some side effects, such as local alkalization and gas cavity, which may lead to a failure of the implant. In this work, a hydroxyapatite (HA) layer was prepared on plasma electrolytic oxidization (PEO) coating by hydrothermal treatment (HT) to fabricate a PEO/HT composite coating on biodegradable AZ31 alloy. The in vitro degradation behaviors of all samples were evaluated in simulated body fluid (SBF) and their surface cytocompatibility was also investigated by evaluating the adhesion and proliferation of osteoblast cells (MC3T3-E1). The results showed that the HA layer consisted of a dense inner layer and a needle-like outer layer, which successfully sealed the PEO coating. The in vitro degradation tests showed that the PEO/HT composite coating improved the corrosion resistance of AZ31 alloy in SBF, presenting nearly no severe local alkalization and hydrogen evolution. The lasting corrosion resistance of the PEO/HT composite coating may attribute to the new hydroxyapatite formation during the degradation process. Moreover, compared with AZ31 alloy and PEO coating, PEO/HT composite coating was more suitable for cells adhesion and proliferation, indicating improved surface cytocompatibility. The results show that the PEO/HT composite coating is promising as protective coating on biodegradable magnesium-based implants to enhance their corrosion resistance as well as improve their surface cytocompatibility for orthopedic applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Accelerated Degradation Behavior and Cytocompatibility of Pure Iron Treated with Sandblasting.

PubMed

Zhou, Juncen; Yang, Yuyun; Alonso Frank, Micael; Detsch, Rainer; Boccaccini, Aldo R; Virtanen, Sannakaisa

2016-10-12

Fe-based materials are of interest for use in biodegradable implants. However, their corrosion rate in the biological environment may be too slow for the targeted applications. In this work, sandblasting is applied as a successful surface treatment for increasing the degradation rate of pure iron in simulated body fluid. Two sandblasting surfaces with different roughness present various surface morphologies but similar degradation products. Electrochemistry tests revealed that sandblasted samples have a higher corrosion rate compared to that of bare iron, and even more noteworthy, the degradation rate of sandblasted samples remains significantly higher during long-term immersion tests. On the basis of our experimental results, the most plausible reasons behind the fast degradation rate are the special properties of sandblasted surfaces, including the change of surface composition (for the early stage), high roughness (occluded surface sites), and high density of dislocations. Furthermore, the cytocompatibility was studied on sandblasting surfaces using human osteoblast-like cells (MG-63) by indirect and direct contact methods. Results revealed that sandblasting treatment brings no adverse effect to the growth of MG-63 cells. This work demonstrates the significant potential of sandblasting for controlling the degradation behavior of iron-based materials for biomedical applications.

Green synthesis of anisotropic gold nanoparticles for photothermal therapy of cancer.

PubMed

Fazal, Sajid; Jayasree, Aswathy; Sasidharan, Sisini; Koyakutty, Manzoor; Nair, Shantikumar V; Menon, Deepthy

2014-06-11

Nanoparticles of varying composition, size, shape, and architecture have been explored for use as photothermal agents in the field of cancer nanomedicine. Among them, gold nanoparticles provide a simple platform for thermal ablation owing to its biocompatibility in vivo. However, the synthesis of such gold nanoparticles exhibiting suitable properties for photothermal activity involves cumbersome routes using toxic chemicals as capping agents, which can cause concerns in vivo. Herein, gold nanoparticles, synthesized using green chemistry routes possessing near-infrared (NIR) absorbance facilitating photothermal therapy, would be a viable alternative. In this study, anisotropic gold nanoparticles were synthesized using an aqueous route with cocoa extract which served both as a reducing and stabilizing agent. The as-prepared gold nanoparticles were subjected to density gradient centrifugation to maximize its NIR absorption in the wavelength range of 800-1000 nm. The particles also showed good biocompatibility when tested in vitro using A431, MDA-MB231, L929, and NIH-3T3 cell lines up to concentrations of 200 μg/mL. Cell death induced in epidermoid carcinoma A431 cells upon irradiation with a femtosecond laser at 800 nm at a low power density of 6 W/cm(2) proved the suitability of green synthesized NIR absorbing anisotropic gold nanoparticles for photothermal ablation of cancer cells. These gold nanoparticles also showed good X-ray contrast when tested using computed tomography (CT), proving their feasibility for use as a contrast agent as well. This is the first report on green synthesized anisotropic and cytocompatible gold nanoparticles without any capping agents and their suitability for photothermal therapy.

Effects of DCPD Cement Chemistry on Degradation Properties and Cytocompatibility: Comparison of MCPM/β-TCP and MCPM/HA Formulations

PubMed Central

Alge, Daniel L.; Goebel, W. Scott; Chu, Tien-Min Gabriel

2013-01-01

Dicalcium phosphate dihydrate (DCPD) cements are attractive biomaterials for bone repair, and a number of different DCPD cement formulations have been proposed in the literature. In this study we have specifically compared monocalcium phosphate monohydrate (MCPM)/hydroxyapatite (HA) and MCPM/β-tricalcium phosphate (β-TCP) formulations to test the hypothesis that DCPD cement chemistry affects the degradation properties and cytocompatibility of the cement. Using simple in vitro models we found that MCPM/β-TCP formulations degraded primarily by DCPD dissolution, which was associated with a slight pH drop and relatively low mass loss. Cytocompatibility testing of cement conditioned culture media revealed no significant change in cell viability relative to the negative control for all of the MCPM/β-TCP formulations. In contrast, the MCPM/HA formulations were prone to undergo rapid conversion of DCPD to HA, resulting in a sharp pH drop and extensive mass loss. A stoichiometric excess of HA in the cement was found to accelerate the conversion process, and significant cytotoxicity was observed for the MCPM/HA formulations containing excess HA. Collectively, these results show that, although the product of the setting reaction is the same, DCPD cements produced with MCPM/HA and MCPM/β-TCP formulations differ significantly in their degradation properties and cytocompatibility. These differences may have important implications for the selection of a DCPD cement formulation for clinical application. PMID:23428798

Cytocompatibility of Mg Alloys and the Effect of Cells on their Degradation in Biological Environment

NASA Astrophysics Data System (ADS)

Yamamoto, Akiko; Kohyama, Yuko

Biomedical application of magnesium and its alloys are highly anticipated since their corrosion reaction with water can be utilized as degradability inside the human body. Degradation ratio of Mg alloys severely influences not only their mechanical integrity along the implantation period but also their biocompatibility since toxicological reaction of surrounding tissue depends on the amount and kind of released metal ions. In this study, pure Mg and AZ-system Mg alloys were employed for cytocompatibility evaluation and the effect of cells on the degradation of the metal specimens during cell culture was also examined. Cells could grow on pure Mg and low-Al content alloy but not on high-Al content alloys even though they release less Mg2+ ions than low-Al content alloy. Higher Mg2+ ion release was observed from the specimens with good cell growth.

In Vitro Corrosion and Cytocompatibility Properties of Nano-Whisker Hydroxyapatite Coating on Magnesium Alloy for Bone Tissue Engineering Applications

PubMed Central

Yang, Huawei; Yan, Xueyu; Ling, Min; Xiong, Zuquan; Ou, Caiwen; Lu, Wei

2015-01-01

We report here the successful fabrication of nano-whisker hydroxyapatite (nHA) coatings on Mg alloy by using a simple one-step hydrothermal process in aqueous solution. The nHA coating shows uniform structure and high crystallinity. Results indicate that nHA coating is promising for improving the in vitro corrosion and cytocompatibility properties of Mg-based implants and devices for bone tissue engineering. In addition, the simple hydrothermal deposition method used in the current study is also applicable to substrates with complex shapes or surface geometries. PMID:25789500

Revealing nanoparticle assembly under high pressure.

NASA Astrophysics Data System (ADS)

Fan, Hongyou

Precise control of structural parameters through nanoscale engineering to improve optical and electronic properties of functional nanoparticles continuously remains an outstanding challenge. Previous work on nanoparticle assembly has been conducted largely at ambient pressure. Here I will present a new Stress-Induced Fabrication method in which we applied high pressure or stress to nanoparticle arrays to induce structural phase transition and to consolidate new nanomaterials with precisely controlled structures and tunable properties. By manipulating nanoparticle coupling through external pressure, a reversible change in their assemblies and properties can be achieved and demonstrated. In addition, over a certain threshold, the external pressure will force these nanoparticles into contact, thereby allowing the formation and consolidation of one- to three-dimensional nanostructures. Through stress induced nanoparticle assembly, materials engineering and synthesis become remarkably flexible without relying on traditional crystallization process where atoms/ions are locked in a specific crystal structure. Therefore, morphology or architecture can be readily tuned to produce desirable properties for practical applications. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Prevention of nanoparticle coalescence under high-temperature annealing.

PubMed

Mizuno, Mikihisa; Sasaki, Yuichi; Yu, Andrew C C; Inoue, Makoto

2004-12-21

An effective method of employing 3-aminopropyldimethylethoxysilane linker molecules to stabilize 4.4 nm FePt nanoparticle monolayer films on a SiO2 substrate as well as to prevent coalescence of the particles under 800 degrees C annealing is reported. As-deposited FePt nanoparticle films in chemically disordered face-centered-cubic phase transform to mostly chemically ordered L1 0 structure after annealing, while the nanoparticles are free from serious coalescence. The method may fulfill the pressing need to prevent nanoparticle coalescence under high-temperature annealing for the development of FePt nanoparticle based products, such as ultrahigh-density magnetic recording media and novel memory devices.

Anti-sessile bacterial and cytocompatibility properties of CHX-loaded nanohydroxyapatite.

PubMed

Barros, J; Grenho, L; Fernandes, M H; Manuel, C M; Melo, L F; Nunes, O C; Monteiro, F J; Ferraz, M P

2015-06-01

Nanohydroxyapatite possesses exceptional biocompatibility and bioactivity regarding bone cells and tissues, justifying its use as a coating material or as a bone substitute. Unfortunately, this feature may also encourage bacterial adhesion and biofilm formation. Surface functionalization with antimicrobials is a promising strategy to reduce the likelihood of bacterial infestation and colonization on medical devices. Chlorhexidine digluconate is a common and effective antimicrobial agent used for a wide range of medical applications. The purpose of this work was the development of a nanoHA biomaterial loaded with CHX to prevent surface bacterial accumulation and, simultaneously, with good cytocompatibility, for application in the medical field. CHX (5-1500 mg/L) was loaded onto nanoHA discs and the materials were evaluated for CHX adsorption and release profile, physic-chemical features, antibacterial activity against Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis, and cytocompatibility toward L929 fibroblasts. Results showed that the adsorption of CHX on nanoHA surface occurred by electrostatic interactions between the cationic group of CHX and the phosphate group of nanoHA. The release of CHX from CHX-loaded nanoHA showed a fast initial rate followed by a slower kinetics release, due to constraints caused by dilution and diffusion-limiting processes. NanoHA.50 to nanoHA.1500 showed strong anti-sessile activity, inhibiting bacterial adhesion and the biofilm formation. CHX-nanoHA caused a dose- and time-dependent inhibitory effect on the proliferation of fibroblasts for nanoHA.100 to nanoHA.1500. Cellular behavior on nanoHA.5 and nanoHA.50 was similar to control. Therefore, CHX-loaded nanoHA surfaces appear as a promising alternative to prevention of devices-related infections. Copyright © 2015 Elsevier B.V. All rights reserved.

Engineering live cell surfaces with functional polymers via cytocompatible controlled radical polymerization

NASA Astrophysics Data System (ADS)

Niu, Jia; Lunn, David J.; Pusuluri, Anusha; Yoo, Justin I.; O'Malley, Michelle A.; Mitragotri, Samir; Soh, H. Tom; Hawker, Craig J.

2017-06-01

The capability to graft synthetic polymers onto the surfaces of live cells offers the potential to manipulate and control their phenotype and underlying cellular processes. Conventional grafting-to strategies for conjugating preformed polymers to cell surfaces are limited by low polymer grafting efficiency. Here we report an alternative grafting-from strategy for directly engineering the surfaces of live yeast and mammalian cells through cell surface-initiated controlled radical polymerization. By developing cytocompatible PET-RAFT (photoinduced electron transfer-reversible addition-fragmentation chain-transfer polymerization), synthetic polymers with narrow polydispersity (Mw/Mn < 1.3) could be obtained at room temperature in 5 minutes. This polymerization strategy enables chain growth to be initiated directly from chain-transfer agents anchored on the surface of live cells using either covalent attachment or non-covalent insertion, while maintaining high cell viability. Compared with conventional grafting-to approaches, these methods significantly improve the efficiency of grafting polymer chains and enable the active manipulation of cellular phenotypes.

[Cytocompatibility of two porous bioactive glass-ceramic in vitro].

PubMed

Zhang, Yan; Jiang, Xinquan; Zhang, Xiuli; Wang, Deping; Zhen, Lei

2013-06-01

To compare the cytocompatibility of two kinds porous bioactive glass-ceramic made by same raw materials. Apatite/wollastonite bioactive glass-ceramic (4006) were prepared by sol-gel method, and bioactive glass (45S5) were prepared by melting method. Bone marrow stromal cells (BMSCs) were cultivated, differentiated and proliferated into osteoblasts, from a rabbit's marrow in the differentiatiofn culture medium with active function. The viability of BMSCs cultivated with extraction of these two kinds of biomaterial, which could represent the cytotoxicity effect of 4006 and 45S5 against BMSCs, was evaluated by the MTp assay. BMSCs were seeded and cocultivated with two kinds of biomaterial scaffolds respectively in vitro. The proliferation and biological properties of cells adhered to scaffolds were observed by inverted phase contrast microscope, scanning electron microscope (SEM), and environmental scanning electron microscope (ESEM), and a suitable cell amount for seeding on the scaffold was searched. There was no difference on the viability of BMSCs only cultured for one day by complete extract of 4006 and culture medium (P>0.05), but there was significant difference between them when the cells had been cultured for 3 days(P<0.01). The extract of 45S5 had significantly higher cytotoxicity than extract of culture medium (P<0.01). The BMSCs adhered, spread, and proliferated throughout the pores of the scaffold 4006, and the amount of cells adhered to 4006 was more than to 45S5. The adhered cells to 4006 increased with the rising amount of cells seeded. And 2 x 10(7) cells.mL-1 suspension resulted inthe highest cell adherence during the comparative cells adherence test. Apatite/woolastonite bioac tive glass-ceramic has good bioactivity and cytocompatibility. Therefore, it may have the potential to be a new cell vehicle for bone tissue engineering. And the suitable seeding cell amount of apatite/wollastonite bioactive glass-ceramic should be 2x10(7) cells.mL-1 or even

Guanidine hydrochloride embedded polyurethanes as antimicrobial and absorptive wound dressing membranes with promising cytocompatibility.

PubMed

Sahraro, Maryam; Yeganeh, Hamid; Sorayya, Marziyeh

2016-02-01

Preparation and assessments of novel absorptive wound dressing materials with efficient antimicrobial activity as well as very good cytocompatibility were described in this work. An amine terminated poly(hexamethylene guanidine hydrochloride) was prepared and used as curing agent of different epoxy-terminated polyurethane prepolymers. The structures of prepared materials were elucidated by evaluation of their (1)H NMR and FTIR spectra. The recorded tensile strength of membranes confirmed the excellent dimensional stability of the film type dressings even at fully hydrated conditions. Therefore, these dressings could protect the wound bed from external forces during the healing period. The structurally optimized dressing membranes could preserve the desired moist environment over the wounded area, as a result of their balanced equilibrium, water absorption and water vapor transmission rate. Therefore, a very good condition for stimulation of self-healing of wound bed was attained. Also, owing to the presence of guanidine hydrochloride moieties embedded into the structure of dressings, efficient antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans were detected. In vitro cytotoxicity assay of the prepared dressings revealed cytocompatibility of these materials against fibroblast cells. Therefore, they could support cell growth and proliferation at the wounded area. Copyright © 2015 Elsevier B.V. All rights reserved.

Cellulose/soy protein isolate composite membranes: evaluations of in vitro cytocompatibility with Schwann cells and in vivo toxicity to animals.

PubMed

Luo, Lihua; Gong, Wenrong; Zhou, Yi; Yang, Lin; Li, Daokun; Huselstein, Celine; Wang, Xiong; He, Xiaohua; Li, Yinping; Chen, Yun

2015-01-01

To evaluate the in vitro cytocompatibility of cellulose/soy protein isolate composite membranes (CSM) with Schwann cells and in vivo toxicity to animals. A series of cellulose/soy protein isolate composite membranes (CSM) were prepared by blending, solution casting and coagulation process. The cytocompatibility of the CSM to Schwann cells were evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and by direct cells culture of Schwann cells on the surfaces of the CSM, respectively. The in vivo toxicity of the CSM to animals were also evaluated by acute toxicity testing, skin sensitization testing, pyrogen testing and intracutaneous stimulation testing, respectively, according to the ISO 10993 standard. The MTT assay showed that the cell viability of Schwann cells cultured in extracts from the CSM was higher than that from the neat cellulose membrane without containing SPI component. The direct cells culture indicated that the Schwann cells could attach and grow well on the surface of the CSM and the incorporation of SPI into cellulose contributed to improvement of cell adhesion and proliferation. The evaluations of in vivo biological safety suggested that the CSM showed no acute toxicity, no skin sensitization and no intracutaneous stimulation to the experimental animals. The CSM had in vitro cytocompatibility with Schwann cells and biological safety to animals, suggesting potential for the applications as nerve conduit for the repair of nerve defect.

Novel highly ordered core–shell nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dey, Sonal; Hossain, Mohammad D.; Mayanovic, Robert A.

2016-10-26

Core–shell nanoparticles have potential for a wide range of applications due to the tunability of their magnetic, catalytic, electronic, optical, and other physicochemical properties. A frequent drawback in the design of core–shell nanoparticles and nanocrystals is the lack of control over an extensive, disordered, and compositionally distinct interface that occurs due to the dissimilarity of structural and compositional phases of the core and shell. In this work, we demonstrate a new hydrothermal nanophase epitaxy (HNE) technique to synthesize highly structurally ordered α-Cr 2O 3@α-Co 0.38Cr 1.62O 2.92 inverted core–shell nanoparticles (CSNs) with evidence for the nanoscale growth of corundum structuremore » beginning from the core and extending completely into the shell of the CSNs with minimal defects at the interface. The high-resolution TEM results show a sharp interface exhibiting epitaxial atomic registry of shell atoms over highly ordered core atoms. The XPS and Co K-edge XANES analyses indicate the +2 oxidation state of cobalt is incorporated in the shell of the CSNs. Our XPS and EXAFS results are consistent with oxygen vacancy formation in order to maintain charge neutrality upon substitution of the Co 2+ ion for the Cr 3+ ion in the α-Co 0.38Cr 1.62O 2.92 shell. Furthermore, the CSNs exhibit the magnetic exchange bias effect, which is attributed to the exchange anisotropy at the interface made possible by the nanophase epitaxial growth of the α-Co 0.38Cr 1.62O 2.92 shell on the α-Cr 2O 3 core of the nanoparticles. The combination of a well-structured, sharp interface and novel nanophase characteristics is highly desirable for nanostructures having enhanced magnetic properties.« less

Interface design and reinforced features of arrowroot (Maranta arundinacea) starch/polyester-based membranes: Preparation, antioxidant activity, and cytocompatibility.

PubMed

Wu, Chin-San; Liao, Hsin-Tzu

2017-01-01

The structural, mechanical, antioxidant, and cytocompatibility properties of membranes prepared from the polyhydroxyalkanoate (PHA) and arrowroot (Maranta arundinacea) starch powder (ASP) blend (PHA/ASP) were studied. The acrylic acid-grafted PHA (PHA-g-AA) and the coupling agent treated ASP (TASP) were used to enhance the desired characteristics of these membranes. The PHA-g-AA/TASP membranes had better mechanical properties than the PHA/ASP membrane. This effect was attributed to greater compatibility between the grafted PHA and TASP. The water resistance of the PHA-g-AA/TASP membranes was greater than that of the PHA/ASP membranes, and a cytocompatibility evaluation with human foreskin fibroblasts (FBs) indicated that both materials were nontoxic. Moreover, both ASP and TASP enhanced the polyphenol content and antioxidant properties of the membranes. PHA-g-AA/TASP and PHA/ASP membranes had better antioxidant activity than the control group. Copyright © 2016 Elsevier B.V. All rights reserved.

Cytocompatibility of Direct Laser Interference-patterned Titanium Surfaces for Implants.

PubMed

Hartjen, Philip; Nada, Ola; Silva, Thiago Gundelwein; Precht, Clarissa; Henningsen, Anders; Holthaus, Marzellus GROßE; Gulow, Nikolai; Friedrich, Reinhard E; Hanken, Henning; Heiland, Max; Zwahr, Christoph; Smeets, Ralf; Jung, Ole

2017-01-01

In an effort to generate titanium surfaces for implants with improved osseointegration, we used direct laser interference patterning (DLIP) to modify the surface of pure titanium grade 4 of four different structures. We assessed in vitro cytoxicity and cell attachment, as well as the viability and proliferation of cells cultured directly on the surfaces. Attachment of the cells to the modified surfaces was comparably good compared to that of cells on grit-blasted and acid-etched reference titanium surfaces. In concordance with this, viability and proliferation of the cells directly cultured on the specimens were similar on all the titanium surfaces, regardless of the laser modification, indicating good cytocompatibility. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Biophysically defined and cytocompatible covalently adaptable networks as viscoelastic 3D cell culture systems.

PubMed

McKinnon, Daniel D; Domaille, Dylan W; Cha, Jennifer N; Anseth, Kristi S

2014-02-12

Presented here is a cytocompatible covalently adaptable hydrogel uniquely capable of mimicking the complex biophysical properties of native tissue and enabling natural cell functions without matrix degradation. Demonstrated is both the ability to control elastic modulus and stress relaxation time constants by more than an order of magnitude while predicting these values based on fundamental theoretical understanding and the simulation of muscle tissue and the encapsulation of myoblasts. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantifying Nanoparticle Internalization Using a High Throughput Internalization Assay.

PubMed

Mann, Sarah K; Czuba, Ewa; Selby, Laura I; Such, Georgina K; Johnston, Angus P R

2016-10-01

The internalization of nanoparticles into cells is critical for effective nanoparticle mediated drug delivery. To investigate the kinetics and mechanism of internalization of nanoparticles into cells we have developed a DNA molecular sensor, termed the Specific Hybridization Internalization Probe - SHIP. Self-assembling polymeric 'pHlexi' nanoparticles were functionalized with a Fluorescent Internalization Probe (FIP) and the interactions with two different cell lines (3T3 and CEM cells) were studied. The kinetics of internalization were quantified and chemical inhibitors that inhibited energy dependent endocytosis (sodium azide), dynamin dependent endocytosis (Dyngo-4a) and macropinocytosis (5-(N-ethyl-N-isopropyl) amiloride (EIPA)) were used to study the mechanism of internalization. Nanoparticle internalization kinetics were significantly faster in 3T3 cells than CEM cells. We have shown that ~90% of the nanoparticles associated with 3T3 cells were internalized, compared to only 20% of the nanoparticles associated with CEM cells. Nanoparticle uptake was via a dynamin-dependent pathway, and the nanoparticles were trafficked to lysosomal compartments once internalized. SHIP is able to distinguish between nanoparticles that are associated on the outer cell membrane from nanoparticles that are internalized. This study demonstrates the assay can be used to probe the kinetics of nanoparticle internalization and the mechanisms by which the nanoparticles are taken up by cells. This information is fundamental for engineering more effective nanoparticle delivery systems. The SHIP assay is a simple and a high-throughput technique that could have wide application in therapeutic delivery research.

High velocity collisions of nanoparticles

NASA Astrophysics Data System (ADS)

Johnson, Donald F.; Mattson, William D.

2017-01-01

Nanoparticles (NPs) are a unique class of material with highly functionalizable surfaces and exciting applications. With a large surface-to-volume ratio and potentially high surface tension, shocked nanoparticles might display unique materials behavior. Using density functional theory, we have simulated high-velocity NP collisions under a variety of conditions. NPs composed of diamond-C, cubic-BN, and diamond-Si were considered with particle sizes up to 3.5 nm diameter. Additional simulations involved NPs that were destabilized by incorporating internal strain. The initial spherical NP structures were carved out of bulk crystals while the NPs with internal strain were constructed as a dense core (compressive strain) encompassed by a thin shell (tensile strain). Both on-axis and off-axis collisions were simulated at 10 km/s relative velocity. The amount of internal strain was artificially increased by creating a dense inner core with bond lengths compressed up to 8%. Collision dynamics, shock propagation, and fragmentation will be analyzed, but the simulation are ongoing and results are not finalized. The effect of material properties, internal strain, and collision velocity will be discussed.

Fabrication and Testing of Electrospun Polyurethane Blended with Chitosan Nanoparticles for Vascular Graft Applications.

PubMed

Subramaniam, Ranjeeta; Mani, Mohan Prasath; Jaganathan, Saravana Kumar

2018-04-26

In this study, a small vascular graft based on polyurethane (PU) blended with chitosan (Ch) nanoparticles was fabricated using electrospinning technique. Initially, the chitosan nanoparticles were synthesized using ionic gelation method. UV-Vis spectrophotometer confirmed the presence of synthesized Ch nanoparticles by exhibiting absorption peak at 288 nm and the Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the existence of the chitosan. Further, the synthesized Ch nanoparticles showed size diameter in the range of 134 ± 58 nm as measured using ImageJ. In the electrospun PU/chitosan graft, the fiber diameter and pore size diameter was found to be reduced compared to the pure PU owing to incorporation of chitosan into PU matrix. The FTIR spectrum revealed the presence of chitosan in the prepared nanocomposite membrane by the formation of the hydrogen bond and peak shift of CH and NH stretching. Moreover, the contact angle measurements revealed that the prepared graft showed decreased contact angle indicating hydrophilic nature compared to the pristine PU. The cytocompatibility studies revealed the non-toxic behavior of the fabricated graft. Hence, the prepared graft exhibiting significant physiochemical and non-toxic properties may be a plausible candidate for cardiovascular graft applications.

Repair of calvarial bone defects in mice using electrospun polystyrene scaffolds combined with β-TCP or gold nanoparticles.

PubMed

Terranova, Lisa; Dragusin, Diana Maria; Mallet, Romain; Vasile, Eugeniu; Stancu, Izabela-Cristina; Behets, Catherine; Chappard, Daniel

2017-02-01

Non-biodegradable porous polystyrene (PS) scaffolds, composed of microfibers, have been prepared by electrospinning for the reconstruction of large bone defects. PS microfibers were prepared by incorporating β-TCP grains inside the polymer or grafting gold nanoparticles surface functionalized with mercaptosuccinic acid. Cytocompatibility of the three types of scaffolds (PS, β-TCP-PS and Au-PS) was studied by seeding human mesenchymal stem cells. Biocompatibility was evaluated by implanting β-TCP-PS and Au-PS scaffolds into a critical size (4mm) calvarial defect in mice. Calvaria were taken 6, 9, and 12 weeks after implantation; newly formed bone and cellular response was analyzed by microcomputed tomography (microCT) and histology. β-TCP-PS scaffolds showed a significantly higher cell proliferation in vitro than on PS or Au-PS alone; clearly, the presence of β-TCP grains improved cytocompatibility. Biocompatibility study in the mouse calvaria model showed that β-TCP-PS scaffolds were significantly associated with more newly-formed bone than Au-PS. Bone developed by osteoconduction from the defect margins to the center. A dense fibrous connective tissue containing blood vessels was identified histologically in both types of scaffolds. There was no inflammatory foci nor giant cell in these areas. AuNPs aggregates were identified histologically in the fibrosis and also incorporated in the newly-formed bone matrix. Although the different types of PS microfibers appeared cytocompatible during the in vitro experiment, they appeared biotolerated in vivo since they induced a fibrotic reaction associated with newly formed bone. Copyright © 2016 Elsevier Ltd. All rights reserved.

New thermosensitive nanoparticles prepared by biocompatible pegylated aliphatic polyester block copolymers for local cancer treatment.

PubMed

Karavelidis, Vassilios; Bikiaris, Dimitrios; Avgoustakis, Konstantinos

2015-02-01

New pegylated thermosensitive polymers were developed to study them as drug vehicles in targeting release nanoparticulate systems of anticancer drugs. The drug vehicles were prepared in the form of core-shell nanoparticles using novel polymeric materials synthesized by copolymerization of poly(propylene adipate) (PPAd) and methoxy-polyethylene glycol (mPEG) with different molecular weights. The physical and chemical properties of the synthesized mPEG-PPAd copolymers were studied using several techniques, and their cytocompatibility was evaluated. For drug nanoencapsulation, a water in oil (W/O) emulsification and solvent evaporation technique was used and the prepared nanoparticles were studied for their physical properties, morphology, drug release and anticancer efficacy against cancer cell lines. The size of the nanoparticles lied in a range suitable for tumour targeting. Drug release was affected by the composition of polymer, the temperature and pH of the release medium. The release results obtained indicate that judicious selection of nanoparticles composition may allow for enhanced drug delivery to the tumours following application of local hyperthermia. The paclitaxel-loaded mPEG-PPAd nanoparticles were found to be cytotoxic against to the human hepatoma HepG2) and the human epithelial (HeLa) cancer cell lines. Enhanced cytotoxicity against the HeLa cells was observed at elevated temperature (42°C compared with 37°C), providing support for the potential usefulness of the mPEG-PPAd nanoparticles for the development of thermo-sensitive anticancer drug delivery systems. © 2014 Royal Pharmaceutical Society.

Advances in highly doped upconversion nanoparticles.

PubMed

Wen, Shihui; Zhou, Jiajia; Zheng, Kezhi; Bednarkiewicz, Artur; Liu, Xiaogang; Jin, Dayong

2018-06-20

Lanthanide-doped upconversion nanoparticles (UCNPs) are capable of converting near-infra-red excitation into visible and ultraviolet emission. Their unique optical properties have advanced a broad range of applications, such as fluorescent microscopy, deep-tissue bioimaging, nanomedicine, optogenetics, security labelling and volumetric display. However, the constraint of concentration quenching on upconversion luminescence has hampered the nanoscience community to develop bright UCNPs with a large number of dopants. This review surveys recent advances in developing highly doped UCNPs, highlights the strategies that bypass the concentration quenching effect, and discusses new optical properties as well as emerging applications enabled by these nanoparticles.

High-spatial-resolution nanoparticle x-ray fluorescence tomography

NASA Astrophysics Data System (ADS)

Larsson, Jakob C.; Vâgberg, William; Vogt, Carmen; Lundström, Ulf; Larsson, Daniel H.; Hertz, Hans M.

2016-03-01

X-ray fluorescence tomography (XFCT) has potential for high-resolution 3D molecular x-ray bio-imaging. In this technique the fluorescence signal from targeted nanoparticles (NPs) is measured, providing information about the spatial distribution and concentration of the NPs inside the object. However, present laboratory XFCT systems typically have limited spatial resolution (>1 mm) and suffer from long scan times and high radiation dose even at high NP concentrations, mainly due to low efficiency and poor signal-to-noise ratio. We have developed a laboratory XFCT system with high spatial resolution (sub-100 μm), low NP concentration and vastly decreased scan times and dose, opening up the possibilities for in-vivo small-animal imaging research. The system consists of a high-brightness liquid-metal-jet microfocus x-ray source, x-ray focusing optics and an energy-resolving photon-counting detector. By using the source's characteristic 24 keV line-emission together with carefully matched molybdenum nanoparticles the Compton background is greatly reduced, increasing the SNR. Each measurement provides information about the spatial distribution and concentration of the Mo nanoparticles. A filtered back-projection method is used to produce the final XFCT image.

Carbothermal shock synthesis of high-entropy-alloy nanoparticles

NASA Astrophysics Data System (ADS)

Yao, Yonggang; Huang, Zhennan; Xie, Pengfei; Lacey, Steven D.; Jacob, Rohit Jiji; Xie, Hua; Chen, Fengjuan; Nie, Anmin; Pu, Tiancheng; Rehwoldt, Miles; Yu, Daiwei; Zachariah, Michael R.; Wang, Chao; Shahbazian-Yassar, Reza; Li, Ju; Hu, Liangbing

2018-03-01

The controllable incorporation of multiple immiscible elements into a single nanoparticle merits untold scientific and technological potential, yet remains a challenge using conventional synthetic techniques. We present a general route for alloying up to eight dissimilar elements into single-phase solid-solution nanoparticles, referred to as high-entropy-alloy nanoparticles (HEA-NPs), by thermally shocking precursor metal salt mixtures loaded onto carbon supports [temperature ~2000 kelvin (K), 55-millisecond duration, rate of ~105 K per second]. We synthesized a wide range of multicomponent nanoparticles with a desired chemistry (composition), size, and phase (solid solution, phase-separated) by controlling the carbothermal shock (CTS) parameters (substrate, temperature, shock duration, and heating/cooling rate). To prove utility, we synthesized quinary HEA-NPs as ammonia oxidation catalysts with ~100% conversion and >99% nitrogen oxide selectivity over prolonged operations.

Electroactive Polymer Nanoparticles Exhibiting Photothermal Properties

PubMed Central

Cantu, Travis; Rodier, Bradley; Iszard, Zachary; Kilian, Alissa; Pattani, Varun; Walsh, Kyle; Weber, Katharina; Tunnell, James; Betancourt, Tania; Irvin, Jennifer

2016-01-01

A method for the synthesis of electroactive polymers is demonstrated, starting with the synthesis of extended conjugation monomers using a three-step process that finishes with Negishi coupling. Negishi coupling is a cross-coupling process in which a chemical precursor is first lithiated, followed by transmetallation with ZnCl2. The resultant organozinc compound can be coupled to a dibrominated aromatic precursor to give the conjugated monomer. Polymer films can be prepared via electropolymerization of the monomer and characterized using cyclic voltammetry and ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy. Nanoparticles (NPs) are prepared via emulsion polymerization of the monomer using a two-surfactant system to yield an aqueous dispersion of the polymer NPs. The NPs are characterized using dynamic light scattering, electron microscopy, and UV-Vis-NIR-spectroscopy. Cytocompatibility of NPs is investigated using the cell viability assay. Finally, the NP suspensions are irradiated with a NIR laser to determine their effectiveness as potential materials for photothermal therapy (PTT). PMID:26780244

Glycosaminoglycan-functionalized poly-lactide-co-glycolide nanoparticles: synthesis, characterization, cytocompatibility, and cellular uptake

PubMed Central

Lamichhane, Surya P; Arya, Neha; Ojha, Nirdesh; Kohler, Esther; Shastri, V Prasad

2015-01-01

The efficient delivery of chemotherapeutics to the tumor via nanoparticle (NP)-based delivery systems remains a significant challenge. This is compounded by the fact that the tumor is highly dynamic and complex environment composed of a plurality of cell types and extracellular matrix. Since glycosaminoglycan (GAG) production is altered in many diseases (or pathologies), NPs bearing GAG moieties on the surface may confer some unique advantages in interrogating the tumor microenvironment. In order to explore this premise, in the study reported here poly-lactide-co-glycolide (PLGA) NPs in the range of 100–150 nm bearing various proteoglycans were synthesized by a single-step nanoprecipitation and characterized. The surface functionalization of the NPs with GAG moieties was verified using zeta potential measurements and X-ray photoelectron spectroscopy. To establish these GAG-bearing NPs as carriers of therapeutics, cellular toxicity assays were undertaken in lung epithelial adenocarcinoma (A549) cells, human pulmonary microvascular endothelial cells (HPMEC), and renal proximal tubular epithelial cells. In general NPs were well tolerated over a wide concentration range (100–600 μg/mL) by all cell types and were taken up to appreciable extents without any adverse cell response in A549 cells and HPMEC. Further, GAG-functionalized PLGA NPs were taken up to different extents in A459 cells and HPMEC. In both cell systems, the uptake of heparin-modified NPs was diminished by 50%–65% in comparison to that of unmodified PLGA. Interestingly, the uptake of chondroitin sulfate NPs was the highest in both cell systems with 40%–60% higher uptake when compared with that of PLGA, and this represented an almost twofold difference over heparin-modified NPs. These findings suggest that GAG modification can be explored as means of changing the uptake behavior of PLGA NPs and these NP systems have potential in cancer therapy. PMID:25632234

Electrophoretic deposition of colloidal particles on Mg with cytocompatibility, antibacterial performance, and corrosion resistance.

PubMed

Sun, Jiadi; Zhu, Ye; Meng, Long; Chen, Peng; Shi, Tiantian; Liu, Xiaoya; Zheng, Yufeng

2016-11-01

Magnesium (Mg) has recently received increasing attention due to its unique biological performance, including cytocompatibility, antibacterial and biodegradable properties. However, rapid corrosion in physiological environment and potential toxicity limits its clinical applications. To improve the corrosion resistance meanwhile not compromise other excellent performance, self-assembled colloidal particles were deposited onto magnesium surfaces in ethanol by a simple and effective electrophoretic deposition (EPD) method. The fabricated functional nanostructured coatings were investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analyses, and scanning electron microscopy (SEM). The electrochemical test, pH value, and Mg ion concentration data show that the corrosion resistance of Mg samples is enhanced appreciably after surface treatment. In vitro cellular response and antibacterial capability of the modified Mg substrates are performed. Significantly increased cell adhesion and viability are observed from the coated Mg samples, and the amounts of adherent bacteria on the treated Mg surfaces diminish remarkably compared to the bare Mg. Furthermore, the bare and coated Mg samples were implanted in New Zealand white rabbits for 12 weeks to examine the in vivo long-term corrosion performance and in situ inflammation behavior. The experiment results confirmed that compared with bare Mg substrate the corrosion and foreign-body reactions of the coated Mg samples were suppressed. The above results suggested that our coatings, which effectively enhance the biocompatibility, antimicrobial properties, and corrosion resistance of Mg substrate, provide a simple and practical strategy to expedite clinical acceptance of biodegradableMg and its alloys. Biomedical Mg metals have been considered as promising biodegradable implants because of their intended functions, such as cytocompatibility, antibacterial, and biodegradable properties. However

Cytocompatibility of Siloxane-Containing Vaterite/Poly(l-lactic acid) Composite Coatings on Metallic Magnesium.

PubMed

Yamada, Shinya; Maeda, Hirotaka; Obata, Akiko; Lohbauer, Ulrich; Yamamoto, Akiko; Kasuga, Toshihiro

2013-12-12

Poly(l-lactic acid)-based films which include 60 wt % of vaterite (V) or siloxane-containing vaterite (SiV) were coated on a pure magnesium substrate, denoted by PLLA/V or PLLA/SiV, respectively, to suppress early corrosion and improve its cytocompatibility. Both coating films adhered to the Mg substrate with 2.3-2.8 MPa of tensile bonding strength. Soaking test for 7 days in α-modified minimum essential medium revealed that the morphological instability of the PLLA/V film caused a higher amount of Mg 2+ ion to be released from the coating sample. On the other hand, in the case of the coating with the PLLA/SiV film, no morphological change even after the soaking test was observed, owing to the suppression of the degradation rate. In cell culture tests, the proliferation of mouse osteoblast-like cell (MC3T3-E1) was significantly enhanced by both coatings, in comparison with the uncoated magnesium substrate. The cell morphology revealed that a few less-spread cells were observed on the PLLA/V film, while more elongated cells were done on the PLLA/SiV film. The cells on the PLLA/SiV film exhibited an extremely higher alkaline phosphatase activity after 21 days of incubation than that on the PLLA/V one. The PLLA/SiV film suppressed the early corrosion and enhanced cytocompatibility on metallic magnesium.

Cytocompatibility of Siloxane-Containing Vaterite/Poly(l-lactic acid) Composite Coatings on Metallic Magnesium

PubMed Central

Yamada, Shinya; Maeda, Hirotaka; Obata, Akiko; Lohbauer, Ulrich; Yamamoto, Akiko; Kasuga, Toshihiro

2013-01-01

Poly(l-lactic acid)-based films which include 60 wt % of vaterite (V) or siloxane-containing vaterite (SiV) were coated on a pure magnesium substrate, denoted by PLLA/V or PLLA/SiV, respectively, to suppress early corrosion and improve its cytocompatibility. Both coating films adhered to the Mg substrate with 2.3–2.8 MPa of tensile bonding strength. Soaking test for 7 days in α-modified minimum essential medium revealed that the morphological instability of the PLLA/V film caused a higher amount of Mg2+ ion to be released from the coating sample. On the other hand, in the case of the coating with the PLLA/SiV film, no morphological change even after the soaking test was observed, owing to the suppression of the degradation rate. In cell culture tests, the proliferation of mouse osteoblast-like cell (MC3T3-E1) was significantly enhanced by both coatings, in comparison with the uncoated magnesium substrate. The cell morphology revealed that a few less-spread cells were observed on the PLLA/V film, while more elongated cells were done on the PLLA/SiV film. The cells on the PLLA/SiV film exhibited an extremely higher alkaline phosphatase activity after 21 days of incubation than that on the PLLA/V one. The PLLA/SiV film suppressed the early corrosion and enhanced cytocompatibility on metallic magnesium. PMID:28788425

Bioactivity and cytocompatibility of zirconia (ZrO(2)) films fabricated by cathodic arc deposition.

PubMed

Liu, Xuanyong; Huang, Anping; Ding, Chuanxian; Chu, Paul K

2006-07-01

Zirconium oxide thin films were fabricated on silicon wafers using a filtered cathodic arc system in concert with oxygen plasma. The structure and phase composition of the zirconium oxide thin films were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), and transmission electron microscopy (TEM). The bioactivity was assessed by investigating the formation of apatite on the film surface after soaking in simulated body fluids. Bone marrow mesenchymal stem cells (BMMSC) were used to further evaluate the cytocompatibility of the materials. The results indicate that the films are composed of stoichiometric ZrO(2) and the composition is quite uniform throughout the thickness. Bone-like apatite can be formed on the surface of the ZrO(2) thin film in our SBF immersion experiments, suggesting that the surface is bioactive. The outermost layer of the ZrO(2) thin film comprises nano-sized particles that can be identified by AFM images taken on the thin film surface and TEM micrographs obtained from the interface between the ZrO(2) thin film and apatite layer. The nanostructured surface is believed to be the key factor that apatite is induced to precipitate on the surface. Bone marrow mesenchymal stem cells are observed to grow and proliferate in good states on the film surface. Our results show that ZrO(2) thin films fabricated by cathodic arc deposition exhibit favorable bioactivity and cytocompatibility.

Cytocompatibility of electrospun nanofiber tubular scaffolds for small diameter tissue engineering blood vessels.

PubMed

Xiang, Ping; Li, Min; Zhang, Chao-ying; Chen, Deng-long; Zhou, Zhi-hua

2011-10-01

A tubular scaffold was fabricated by using electrospun polymer solution blends of pNSR32 (recombinant spider silk protein), PCL (polycaprolactone) and Gt (gelatin). The physicochemical properties and cytocompatibility of these scaffolds were investigated. Afterwards, the pNSR32/PCL/Gt tubular scaffold (inner diameter=3mm) showed high porosity of 86.2 ± 2.9%, pore size of 2423 ± 979nm and average fibre diameter of 166 ± 85nm. Water uptake and contact angle of the scaffolds reached 112.0 ± 4.4% and 45.7 ± 13.7°, respectively. SDRAECs (Sprague Dawley Rat Aortic Endothelial Cells) grew and proliferated well and phenotype could be maintained on the composite scaffolds after they had been cultured on the composite scaffolds for 7 days. Compared with pure PCL scaffolds a greater density of viable cells was seen on the composites, especially the pNSR32/PCL/Gt scaffolds. Copyright © 2011 Elsevier B.V. All rights reserved.

Influence of fluoride treatment on surface properties, biodegradation and cytocompatibility of Mg-Nd-Zn-Zr alloy.

PubMed

Zhang, Jian; Kong, Ni; Niu, Jialin; Shi, Yongjuan; Li, Haiyan; Zhou, Yue; Yuan, Guangyin

2014-03-01

Fluoride treatment is a commonly used technique or pre-treatment to optimize the degradation kinetic and improve the biocompatibility of magnesium-based implant. The influence of changed surface properties and degradation kinetics on subsequent protein adsorption and cytocompatibility is critical to understand the biocompatibility of the implant. In this study, a patent magnesium alloy Mg-Nd-Zn-Zr alloy (JDBM) designed for cardiovascular stent application was treated by immersion in hydrofluoric acid. A 1.5 μm thick MgF2 layer was prepared. The surface roughness was increased slightly while the surface zeta potential was changed to a much more negative value after the treatment. Static contact angle test was performed, showing an increase in hydrophilicity and surface energy after the treatment. The MgF2 layer slowed down in vitro degradation rate, but lost the protection effect after 10 days. The treatment enhanced human albumin adsorption while no difference of human fibrinogen adsorption amount was observed. Direct cell adhesion test showed many more live HUVECs retained than bare magnesium alloy. Both treated and untreated JDBM showed no adverse effect on HUVEC viability and spreading morphology. The relationship between changed surface characteristics, degradation rate and protein adsorption, cytocompatibility was also discussed.

Efficient One-Pot Synthesis of Colloidal Zirconium Oxide Nanoparticles for High-Refractive-Index Nanocomposites.

PubMed

Liu, Chao; Hajagos, Tibor Jacob; Chen, Dustin; Chen, Yi; Kishpaugh, David; Pei, Qibing

2016-02-01

Zirconium oxide nanoparticles are promising candidates for optical engineering, photocatalysis, and high-κ dielectrics. However, reported synthetic methods for the colloidal zirconium oxide nanoparticles use unstable alkoxide precursors and have various other drawbacks, limiting their wide application. Here, we report a facile one-pot method for the synthesis of colloidally stable zirconium oxide nanoparticles. Using a simple solution of zirconium trifluoroacetate in oleylamine, highly stable zirconium oxide nanoparticles have been synthesized with high yield, following a proposed amidization-assisted sol-gel mechanism. The nanoparticles can be readily dispersed in nonpolar solvents, forming a long-term stable transparent solution, which can be further used to fabricate high-refractive-index nanocomposites in both monolith and thin-film forms. In addition, the same method has also been extended to the synthesis of titanium oxide nanoparticles, demonstrating its general applicability to all group IVB metal oxide nanoparticles.

Nanoparticle-assisted high photoconductive gain in composites of polymer and fullerene.

PubMed

Chen, Hsiang-Yu; Lo, Michael K F; Yang, Guanwen; Monbouquette, Harold G; Yang, Yang

2008-09-01

Polymer-inorganic nanocrystal composites offer an attractive means to combine the merits of organic and inorganic materials into novel electronic and photonic systems. However, many applications of these composites are limited by the solubility and distribution of the nanocrystals in the polymer matrices. Here we show that blending CdTe nanoparticles into a polymer-fullerene matrix followed by solvent annealing can achieve high photoconductive gain under low applied voltages. The surface capping ligand renders the nanoparticles highly soluble in the polymer blend, thereby enabling high CdTe loadings. An external quantum efficiency as high as approximately 8,000% at 350 nm was achieved at -4.5 V. Hole-dominant devices coupled with atomic force microscopy images show a higher concentration of nanoparticles near the cathode-polymer interface. The nanoparticles and trapped electrons assist hole injection into the polymer under reverse bias, contributing to efficiency values in excess of 100%.

Coatings of Different Carbon Nanotubes on Platinum Electrodes for Neuronal Devices: Preparation, Cytocompatibility and Interaction with Spiral Ganglion Cells.

PubMed

Burblies, Niklas; Schulze, Jennifer; Schwarz, Hans-Christoph; Kranz, Katharina; Motz, Damian; Vogt, Carla; Lenarz, Thomas; Warnecke, Athanasia; Behrens, Peter

2016-01-01

Cochlear and deep brain implants are prominent examples for neuronal prostheses with clinical relevance. Current research focuses on the improvement of the long-term functionality and the size reduction of neural interface electrodes. A promising approach is the application of carbon nanotubes (CNTs), either as pure electrodes but especially as coating material for electrodes. The interaction of CNTs with neuronal cells has shown promising results in various studies, but these appear to depend on the specific type of neurons as well as on the kind of nanotubes. To evaluate a potential application of carbon nanotube coatings for cochlear electrodes, it is necessary to investigate the cytocompatibility of carbon nanotube coatings on platinum for the specific type of neuron in the inner ear, namely spiral ganglion neurons. In this study we have combined the chemical processing of as-delivered CNTs, the fabrication of coatings on platinum, and the characterization of the electrical properties of the coatings as well as a general cytocompatibility testing and the first cell culture investigations of CNTs with spiral ganglion neurons. By applying a modification process to three different as-received CNTs via a reflux treatment with nitric acid, long-term stable aqueous CNT dispersions free of dispersing agents were obtained. These were used to coat platinum substrates by an automated spray-coating process. These coatings enhance the electrical properties of platinum electrodes, decreasing the impedance values and raising the capacitances. Cell culture investigations of the different CNT coatings on platinum with NIH3T3 fibroblasts attest an overall good cytocompatibility of these coatings. For spiral ganglion neurons, this can also be observed but a desired positive effect of the CNTs on the neurons is absent. Furthermore, we found that the well-established DAPI staining assay does not function on the coatings prepared from single-wall nanotubes.

Coatings of Different Carbon Nanotubes on Platinum Electrodes for Neuronal Devices: Preparation, Cytocompatibility and Interaction with Spiral Ganglion Cells

PubMed Central

Schwarz, Hans-Christoph; Kranz, Katharina; Motz, Damian; Vogt, Carla; Lenarz, Thomas; Warnecke, Athanasia; Behrens, Peter

2016-01-01

Cochlear and deep brain implants are prominent examples for neuronal prostheses with clinical relevance. Current research focuses on the improvement of the long-term functionality and the size reduction of neural interface electrodes. A promising approach is the application of carbon nanotubes (CNTs), either as pure electrodes but especially as coating material for electrodes. The interaction of CNTs with neuronal cells has shown promising results in various studies, but these appear to depend on the specific type of neurons as well as on the kind of nanotubes. To evaluate a potential application of carbon nanotube coatings for cochlear electrodes, it is necessary to investigate the cytocompatibility of carbon nanotube coatings on platinum for the specific type of neuron in the inner ear, namely spiral ganglion neurons. In this study we have combined the chemical processing of as-delivered CNTs, the fabrication of coatings on platinum, and the characterization of the electrical properties of the coatings as well as a general cytocompatibility testing and the first cell culture investigations of CNTs with spiral ganglion neurons. By applying a modification process to three different as-received CNTs via a reflux treatment with nitric acid, long-term stable aqueous CNT dispersions free of dispersing agents were obtained. These were used to coat platinum substrates by an automated spray-coating process. These coatings enhance the electrical properties of platinum electrodes, decreasing the impedance values and raising the capacitances. Cell culture investigations of the different CNT coatings on platinum with NIH3T3 fibroblasts attest an overall good cytocompatibility of these coatings. For spiral ganglion neurons, this can also be observed but a desired positive effect of the CNTs on the neurons is absent. Furthermore, we found that the well-established DAPI staining assay does not function on the coatings prepared from single-wall nanotubes. PMID:27385031

High precision and high yield fabrication of dense nanoparticle arrays onto DNA origami at statistically independent binding sites

NASA Astrophysics Data System (ADS)

Takabayashi, Sadao; Klein, William P.; Onodera, Craig; Rapp, Blake; Flores-Estrada, Juan; Lindau, Elias; Snowball, Lejmarc; Sam, Joseph T.; Padilla, Jennifer E.; Lee, Jeunghoon; Knowlton, William B.; Graugnard, Elton; Yurke, Bernard; Kuang, Wan; Hughes, William L.

2014-10-01

High precision, high yield, and high density self-assembly of nanoparticles into arrays is essential for nanophotonics. Spatial deviations as small as a few nanometers can alter the properties of near-field coupled optical nanostructures. Several studies have reported assemblies of few nanoparticle structures with controlled spacing using DNA nanostructures with variable yield. Here, we report multi-tether design strategies and attachment yields for homo- and hetero-nanoparticle arrays templated by DNA origami nanotubes. Nanoparticle attachment yield via DNA hybridization is comparable with streptavidin-biotin binding. Independent of the number of binding sites, >97% site-occupation was achieved with four tethers and 99.2% site-occupation is theoretically possible with five tethers. The interparticle distance was within 2 nm of all design specifications and the nanoparticle spatial deviations decreased with interparticle spacing. Modified geometric, binomial, and trinomial distributions indicate that site-bridging, steric hindrance, and electrostatic repulsion were not dominant barriers to self-assembly and both tethers and binding sites were statistically independent at high particle densities.High precision, high yield, and high density self-assembly of nanoparticles into arrays is essential for nanophotonics. Spatial deviations as small as a few nanometers can alter the properties of near-field coupled optical nanostructures. Several studies have reported assemblies of few nanoparticle structures with controlled spacing using DNA nanostructures with variable yield. Here, we report multi-tether design strategies and attachment yields for homo- and hetero-nanoparticle arrays templated by DNA origami nanotubes. Nanoparticle attachment yield via DNA hybridization is comparable with streptavidin-biotin binding. Independent of the number of binding sites, >97% site-occupation was achieved with four tethers and 99.2% site-occupation is theoretically possible with five

Highly Sensitive NiO Nanoparticle based Chlorine Gas Sensor

NASA Astrophysics Data System (ADS)

Arif, Mohd.; Sanger, Amit; Singh, Arun

2018-03-01

We have synthesized a chemiresistive sensor for chlorine (Cl2) gas in the range of 2-200 ppm based on nickel oxide (NiO) nanoparticles obtained by wet chemical synthesis. The nanoparticles were characterized by x-ray diffraction (XRD) analysis, field-emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, and photoluminescence (PL) spectroscopy. XRD spectra of the sensing layer revealed the cubic phase of NiO nanoparticles. The NiO nanoparticle size was calculated to be ˜ 21 nm using a Williamson-Hall plot. The bandgap of the NiO nanoparticles was found to be 3.13 eV using Tauc plots of the absorbance curve. Fast response time (12 s) and optimum recovery time (˜ 27 s) were observed for 10 ppm Cl2 gas at moderate temperature of 200°C. These results demonstrate the potential application of NiO nanoparticles for fabrication of highly sensitive and selective sensors for Cl2 gas.

Highly-branched anisotropic hybrid nanoparticles at surfaces.

NASA Astrophysics Data System (ADS)

Tsukruk, Vladimir

2009-03-01

We present a brief overview of our recent studies on combined hybrid anisotropic structures composed of inorganic nanoparticles and highly branched molecules such as modified silsesquioxanes polyhedra cores (POSS) with mixed hydrophobic-hydrophilic tails and silver nanowires with functionalized star block copolymer with embedded gold nanoparticles (nanocobs). We demonstrate two-stage melting of that branched POSS and their ability to form monolayer and multilayered LB structures. On the other hand, we observed that silver-BCP-gold nanocobs display extremely bright Raman scattering caused by surface enhanced Raman effect with very different longitudinal and transversal optical properties as revealed by high-resolution confocal Raman microscopy. To study these hybrid nanostructures we applied combined AFM, SEM, TEM, XPS, SERS, UV-vis, and XR techniques.

Cyclodextrin-Modified Porous Silicon Nanoparticles for Efficient Sustained Drug Delivery and Proliferation Inhibition of Breast Cancer Cells.

PubMed

Correia, Alexandra; Shahbazi, Mohammad-Ali; Mäkilä, Ermei; Almeida, Sérgio; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A

2015-10-21

Over the past decade, the potential of polymeric structures has been investigated to overcome many limitations related to nanosized drug carriers by modulating their toxicity, cellular interactions, stability, and drug-release kinetics. In this study, we have developed a successful nanocomposite consisting of undecylenic acid modified thermally hydrocarbonized porous silicon nanoparticles (UnTHCPSi NPs) loaded with an anticancer drug, sorafenib, and surface-conjugated with heptakis(6-amino-6-deoxy)-β-cyclodextrin (HABCD) to show the impact of the surface polymeric functionalization on the physical and biological properties of the drug-loaded nanoparticles. Cytocompatibility studies showed that the UnTHCPSi-HABCD NPs were not toxic to breast cancer cells. HABCD also enhanced the suspensibility and both the colloidal and plasma stabilities of the UnTHCPSi NPs. UnTHCPSi-HABCD NPs showed a significantly increased interaction with breast cancer cells compared to bare NPs and also sustained the drug release. Furthermore, the sorafenib-loaded UnTHCPSi-HABCD NPs efficiently inhibited cell proliferation of the breast cancer cells.

Blood-Vessel Mimicking Structures by Stereolithographic Fabrication of Small Porous Tubes Using Cytocompatible Polyacrylate Elastomers, Biofunctionalization and Endothelialization

PubMed Central

Huber, Birgit; Engelhardt, Sascha; Meyer, Wolfdietrich; Krüger, Hartmut; Wenz, Annika; Schönhaar, Veronika; Tovar, Günter E. M.; Kluger, Petra J.; Borchers, Kirsten

2016-01-01

Blood vessel reconstruction is still an elusive goal for the development of in vitro models as well as artificial vascular grafts. In this study, we used a novel photo-curable cytocompatible polyacrylate material (PA) for freeform generation of synthetic vessels. We applied stereolithography for the fabrication of arbitrary 3D tubular structures with total dimensions in the centimeter range, 300 µm wall thickness, inner diameters of 1 to 2 mm and defined pores with a constant diameter of approximately 100 µm or 200 µm. We established a rinsing protocol to remove remaining cytotoxic substances from the photo-cured PA and applied thio-modified heparin and RGDC-peptides to functionalize the PA surface for enhanced endothelial cell adhesion. A rotating seeding procedure was introduced to ensure homogenous endothelial monolayer formation at the inner luminal tube wall. We showed that endothelial cells stayed viable and adherent and aligned along the medium flow under fluid-flow conditions comparable to native capillaries. The combined technology approach comprising of freeform additive manufacturing (AM), biomimetic design, cytocompatible materials which are applicable to AM, and biofunctionalization of AM constructs has been introduced as BioRap® technology by the authors. PMID:27104576

Epidermal growth factor receptor-targeted lipid nanoparticles retain self-assembled nanostructures and provide high specificity

NASA Astrophysics Data System (ADS)

Zhai, Jiali; Scoble, Judith A.; Li, Nan; Lovrecz, George; Waddington, Lynne J.; Tran, Nhiem; Muir, Benjamin W.; Coia, Gregory; Kirby, Nigel; Drummond, Calum J.; Mulet, Xavier

2015-02-01

Next generation drug delivery utilising nanoparticles incorporates active targeting to specific sites. In this work, we combined targeting with the inherent advantages of self-assembled lipid nanoparticles containing internal nano-structures. Epidermal growth factor receptor (EGFR)-targeting, PEGylated lipid nanoparticles using phytantriol and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-PEG-maleimide amphiphiles were created. The self-assembled lipid nanoparticles presented here have internal lyotropic liquid crystalline nano-structures, verified by synchrotron small angle X-ray scattering and cryo-transmission electron microscopy, that offer the potential of high drug loading and enhanced cell penetration. Anti-EGFR Fab' fragments were conjugated to the surface of nanoparticles via a maleimide-thiol reaction at a high conjugation efficiency and retained specificity following conjugation to the nanoparticles. The conjugated nanoparticles were demonstrated to have high affinity for an EGFR target in a ligand binding assay.Next generation drug delivery utilising nanoparticles incorporates active targeting to specific sites. In this work, we combined targeting with the inherent advantages of self-assembled lipid nanoparticles containing internal nano-structures. Epidermal growth factor receptor (EGFR)-targeting, PEGylated lipid nanoparticles using phytantriol and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-PEG-maleimide amphiphiles were created. The self-assembled lipid nanoparticles presented here have internal lyotropic liquid crystalline nano-structures, verified by synchrotron small angle X-ray scattering and cryo-transmission electron microscopy, that offer the potential of high drug loading and enhanced cell penetration. Anti-EGFR Fab' fragments were conjugated to the surface of nanoparticles via a maleimide-thiol reaction at a high conjugation efficiency and retained specificity following conjugation to the nanoparticles. The conjugated nanoparticles

Preparation, mechanical property and cytocompatibility of freeze-cast porous calcium phosphate ceramics reinforced by phosphate-based glass.

PubMed

Yang, Yanqiu; He, Fupo; Ye, Jiandong

2016-12-01

In this study, phosphate-based glass (PG) was used as a sintering aid for freeze-cast porous biphasic calcium phosphate (BCP) ceramic, which was sintered under a lower temperature (1000°C). The phase composition, pore structure, compressive strength, and cytocompatibility of calcium phosphate composite ceramics (PG-BCP) were evaluated. The results indicated that PG additive reacted with calcium phosphate during the sintering process, forming β-Ca2P2O7; the ions of sodium and magnesium from PG partially substituted the calcium sites of β-calcium phosphate in BCP. The PG-BCP showed good cytocompatibility. The pore width of the porous PG-BCP ceramics was around 50μm, regardless of the amount of PG sintering aid. As the content of PG increased from 0wt.% to 15wt.%, the compressive strength of PG-BCP increased from 0.02 MP to 0.28MPa. When the PG additive was 17.5wt.%, the compressive strength of PG-BCP dramatically increased to 5.66MPa. Addition of 15wt.% PG was the critical point for the properties of PG-BCP. PG is considered as an effective sintering aid for freeze-cast porous bioceramics. Copyright © 2016 Elsevier B.V. All rights reserved.

Multipositional silica-coated silver nanoparticles for high-performance polymer solar cells.

PubMed

Choi, Hyosung; Lee, Jung-Pil; Ko, Seo-Jin; Jung, Jae-Woo; Park, Hyungmin; Yoo, Seungmin; Park, Okji; Jeong, Jong-Ryul; Park, Soojin; Kim, Jin Young

2013-05-08

We demonstrate high-performance polymer solar cells using the plasmonic effect of multipositional silica-coated silver nanoparticles. The location of the nanoparticles is critical for increasing light absorption and scattering via enhanced electric field distribution. The device incorporating nanoparticles between the hole transport layer and the active layer achieves a power conversion efficiency of 8.92% with an external quantum efficiency of 81.5%. These device efficiencies are the highest values reported to date for plasmonic polymer solar cells using metal nanoparticles.

A bioinspired elastin-based protein for a cytocompatible underwater adhesive.

PubMed

Brennan, M Jane; Kilbride, Bridget F; Wilker, Jonathan J; Liu, Julie C

2017-04-01

The development of adhesives that can be applied and create strong bonds underwater is a significant challenge for materials engineering. When the adhesive is intended for biomedical applications, further criteria, such as biocompatibility, must be met. Current biomedical adhesive technologies do not meet these needs. In response, we designed a bioinspired protein system that shows promise to achieve biocompatible underwater adhesion coupled with environmentally responsive behavior that is "smart" - that is, it can be tuned to suit a specific application. The material, ELY 16 , is constructed from an elastin-like polypeptide (ELP) that can be produced in high yields from Escherichia coli and can coacervate in response to environmental factors such as temperature, pH, and salinity. To confer wet adhesion, we utilized design principles from marine organisms such as mussels and sandcastle worms. When expressed, ELY 16 is rich in tyrosine. Upon modification with the tyrosinase enzyme to form mELY 16 , the tyrosine residues are converted to 3,4-dihydroxyphenylalanine (DOPA). Both ELY 16 and mELY 16 exhibit cytocompatibility and significant dry adhesion strength (>2 MPa). Modification with DOPA increases protein adsorption to glass and provides moderate adhesion strength (∼240 kPa) in a highly humid environment. Furthermore, this ELP exhibits a tunable phase transition behavior that can be formulated to coacervate in physiological conditions and provides a convenient mechanism for application underwater. Finally, mELY 16 possesses significantly higher adhesion strength in dry, humid, and underwater environments compared with a commercially available fibrin sealant. To our knowledge, mELY 16 provides the strongest bonds of any rationally designed protein when used completely underwater, and its high yields make it more viable for commercial application compared to natural adhesive proteins. In conclusion, this ELP shows great potential to be a new "smart" underwater

High-throughput profiling of nanoparticle-protein interactions by fluorescamine labeling.

PubMed

Ashby, Jonathan; Duan, Yaokai; Ligans, Erik; Tamsi, Michael; Zhong, Wenwan

2015-02-17

A rapid, high throughput fluorescence assay was designed to screen interactions between proteins and nanoparticles. The assay employs fluorescamine, a primary-amine specific fluorogenic dye, to label proteins. Because fluorescamine could specifically target the surface amines on proteins, a conformational change of the protein upon interaction with nanoparticles will result in a change in fluorescence. In the present study, the assay was applied to test the interactions between a selection of proteins and nanoparticles made of polystyrene, silica, or iron oxide. The particles were also different in their hydrodynamic diameter, synthesis procedure, or surface modification. Significant labeling differences were detected when the same protein incubated with different particles. Principal component analysis (PCA) on the collected fluorescence profiles revealed clear grouping effects of the particles based on their properties. The results prove that fluorescamine labeling is capable of detecting protein-nanoparticle interactions, and the resulting fluorescence profile is sensitive to differences in nanoparticle's physical properties. The assay can be carried out in a high-throughput manner, and is rapid with low operation cost. Thus, it is well suited for evaluating interactions between a larger number of proteins and nanoparticles. Such assessment can help to improve our understanding on the molecular basis that governs the biological behaviors of nanomaterials. It will also be useful for initial examination of the bioactivity and reproducibility of nanomaterials employed in biomedical fields.

Molecular dynamic simulations of the high-speed copper nanoparticles collision with the aluminum surface

NASA Astrophysics Data System (ADS)

Pogorelko, V. V.; Mayer, A. E.

2016-11-01

With the use of the molecular dynamic simulations, we investigated the effect of the high-speed (500 m/s, 1000 m/s) copper nanoparticle impact on the mechanical properties of an aluminum surface. Dislocation analysis shows that a large number of dislocations are formed in the impact area; the total length of dislocations is determined not only by the speed and size of the incoming copper nanoparticle (kinetic energy of the nanoparticle), but by a temperature of the system as well. The dislocations occupy the whole area of the aluminum single crystal at high kinetic energy of the nanoparticle. With the decrease of the nanoparticle kinetic energy, the dislocation structures are formed in the near-surface layer; formation of the dislocation loops takes place. Temperature rise of the system (aluminum substrate + nanoparticle) reduces the total dislocation length in the single crystal of aluminum; there is deeper penetration of the copper atoms in the aluminum at high temperatures. Average energy of the nanoparticles and room temperature of the system are optimal for production of high-quality layers of copper on the aluminum surface.

High-yield synthesis of brookite TiO.sub.2 nanoparticles

DOEpatents

Huber, Dale L [Albuquerque, NM; Monson, Todd C [Albuquerque, NM

2011-05-17

A method for forming non-agglomerated brookite TiO.sub.2 nanoparticles without the use of expensive organic surfactants or high temperature processing. Embodiments of this invention use titanium isopropoxide as the titanium precursor and isopropanol as both the solvent and ligand for ligand-stabilized brookite-phase titania. Isopropanol molecules serve as the ligands interacting with the titania surfaces that stabilize the titania nanoparticles. The isopropanol ligands can be exchanged with other alcohols and other ligands during or after the nanoparticle formation reaction.

Nano-particle modified stationary phases for high-performance liquid chromatography.

PubMed

Nesterenko, Ekaterina P; Nesterenko, Pavel N; Connolly, Damian; He, Xiaoyun; Floris, Patrick; Duffy, Emer; Paull, Brett

2013-08-07

This review covers the latest developments and applications of nano-materials in stationary phase development for various modes of high-performance liquid chromatography. Specific attention is placed upon the development of new composite phases, including the synthetic and immobilisation strategies used, to produce either encapsulated nano-particles, or surface attached nano-particles, layers, coatings and other structures. The resultant chromatographic applications, where applicable, are discussed with comment upon enhanced selectivity and/or efficiency of the nano-particle modified phases, where such effects have been identified. In the main this review covers developments over the past five years and is structured according to the nature of the nano-particles themselves, including carbonaceous, metallic, inorganic, and organopolymer based materials.

Synthesis, characterization, and cytocompatibility of potential cockle shell aragonite nanocrystals for osteoporosis therapy and hormonal delivery.

PubMed

Jaji, Alhaji Zubair; Bakar, Md Zuki Bin Abu; Mahmud, Rozi; Loqman, Mohamad Yusof; Hezmee, Mohamad Noor Mohamad; Isa, Tijani; Wenliang, Fu; Hammadi, Nahidah Ibrahim

2017-01-01

Calcium carbonate is a porous inorganic nanomaterial with huge potential in biomedical applications and controlled drug delivery. This study aimed at evaluating the physicochemical properties and in vitro efficacy and safety of cockle shell aragonite calcium carbonate nanocrystals (ANC) as a potential therapeutic and hormonal delivery vehicle for osteoporosis management. Free and human recombinant parathyroid hormone 1-34 (PTH 1-34)-loaded cockle shell aragonite calcium carbonate nanocrystals (PTH-ANC) were synthesized and evaluated using standard procedures. Transmission electron microscopy and field emission scanning electron microscopy results demonstrated highly homogenized spherical-shaped aragonite nanocrystals of 30±5 nm diameter. PTH-ANC had a zeta potential of -27.6±8.9 mV. The encapsulation efficiency of the formulation was found to be directly proportional to the concentrations of the drug fed. The X-ray diffraction patterns revealed strong crystallizations with no positional change of peaks before and after PTH-ANC synthesis. Fourier transform infrared spectroscopy demonstrated no detectable interactions between micron-sized aragonite and surfactant at molecular level. PTH-ANC formulation was stabilized at pH 7.5, enabling sustained slow release of PTH 1-34 for 168 h (1 week). A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cytocompatibility assay in Human Foetal Osteoblast Cell Line hFOB 1.19 showed that ANC can safely support osteoblast proliferation up to 48 h whereas PTH-ANC can safely support the proliferation at 72 h and beyond due to the sustained slow release of PTH 1-34. It was concluded that due to its biogenic nature, ANC is a cytocompatible antiosteoporotic agent. It doubles as a nanocarrier for the enhancement of efficacy and safety of the bone anabolic PTH 1-34. ANC is expected to reduce the cost, dosage, and dose frequency associated with the use of PTH 1-34 management of primary and secondary forms of osteoporosis.

Synthesis, characterization, and cytocompatibility of potential cockle shell aragonite nanocrystals for osteoporosis therapy and hormonal delivery

PubMed Central

Jaji, Alhaji Zubair; Bakar, Md Zuki Bin Abu; Mahmud, Rozi; Loqman, Mohamad Yusof; Hezmee, Mohamad Noor Mohamad; Isa, Tijani; Wenliang, Fu; Hammadi, Nahidah Ibrahim

2017-01-01

Calcium carbonate is a porous inorganic nanomaterial with huge potential in biomedical applications and controlled drug delivery. This study aimed at evaluating the physicochemical properties and in vitro efficacy and safety of cockle shell aragonite calcium carbonate nanocrystals (ANC) as a potential therapeutic and hormonal delivery vehicle for osteoporosis management. Free and human recombinant parathyroid hormone 1-34 (PTH 1-34)-loaded cockle shell aragonite calcium carbonate nanocrystals (PTH-ANC) were synthesized and evaluated using standard procedures. Transmission electron microscopy and field emission scanning electron microscopy results demonstrated highly homogenized spherical-shaped aragonite nanocrystals of 30±5 nm diameter. PTH-ANC had a zeta potential of −27.6±8.9 mV. The encapsulation efficiency of the formulation was found to be directly proportional to the concentrations of the drug fed. The X-ray diffraction patterns revealed strong crystallizations with no positional change of peaks before and after PTH-ANC synthesis. Fourier transform infrared spectroscopy demonstrated no detectable interactions between micron-sized aragonite and surfactant at molecular level. PTH-ANC formulation was stabilized at pH 7.5, enabling sustained slow release of PTH 1-34 for 168 h (1 week). A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cytocompatibility assay in Human Foetal Osteoblast Cell Line hFOB 1.19 showed that ANC can safely support osteoblast proliferation up to 48 h whereas PTH-ANC can safely support the proliferation at 72 h and beyond due to the sustained slow release of PTH 1-34. It was concluded that due to its biogenic nature, ANC is a cytocompatible antiosteoporotic agent. It doubles as a nanocarrier for the enhancement of efficacy and safety of the bone anabolic PTH 1-34. ANC is expected to reduce the cost, dosage, and dose frequency associated with the use of PTH 1-34 management of primary and secondary forms of osteoporosis

In situ plasma fabrication of ceramic-like structure on polymeric implant with enhanced surface hardness, cytocompatibility and antibacterial capability.

PubMed

Liu, Jun; Zhang, Wei; Shi, Haigang; Yang, Kun; Wang, Gexia; Wang, Pingli; Ji, Junhui; Chu, Paul K

2016-05-01

Polymeric materials are commonly found in orthopedic implants due to their unique mechanical properties and biocompatibility but the poor surface hardness and bacterial infection hamper many biomedical applications. In this study, a ceramic-like surface structure doped with silver is produced by successive plasma implantation of silicon (Si) and silver (Ag) into the polyamine 66 (PA66) substrate. Not only the surface hardness and elastic modulus are greatly enhanced due to the partial surface carbonization and the ceramic-like structure produced by the reaction between energetic Si and the carbon chain of PA66, but also the antibacterial activity is improved because of the combined effects rendered by Ag and SiC structure. Furthermore, the modified materials which exhibit good cytocompatibility upregulate bone-related genes and proteins expressions of the contacted bone mesenchymal stem cells (BMSCs). For the first time, it explores out that BMSCs osteogenesis on the antibacterial ceramic-like structure is mediated via the iNOS and nNOS signal pathways. The results reveal that in situ plasma fabrication of an antibacterial ceramic-like structure can endow PA66 with excellent surface hardness, cytocompatibility, as well as antibacterial capability. © 2016 Wiley Periodicals, Inc.

Evaluation of polymeric gene delivery nanoparticles by nanoparticle tracking analysis and high-throughput flow cytometry.

PubMed

Shmueli, Ron B; Bhise, Nupura S; Green, Jordan J

2013-03-01

Non-viral gene delivery using polymeric nanoparticles has emerged as an attractive approach for gene therapy to treat genetic diseases(1) and as a technology for regenerative medicine(2). Unlike viruses, which have significant safety issues, polymeric nanoparticles can be designed to be non-toxic, non-immunogenic, non-mutagenic, easier to synthesize, chemically versatile, capable of carrying larger nucleic acid cargo and biodegradable and/or environmentally responsive. Cationic polymers self-assemble with negatively charged DNA via electrostatic interaction to form complexes on the order of 100 nm that are commonly termed polymeric nanoparticles. Examples of biomaterials used to form nanoscale polycationic gene delivery nanoparticles include polylysine, polyphosphoesters, poly(amidoamines)s and polyethylenimine (PEI), which is a non-degradable off-the-shelf cationic polymer commonly used for nucleic acid delivery(1,3) . Poly(beta-amino ester)s (PBAEs) are a newer class of cationic polymers(4) that are hydrolytically degradable(5,6) and have been shown to be effective at gene delivery to hard-to-transfect cell types such as human retinal endothelial cells (HRECs)(7), mouse mammary epithelial cells(8), human brain cancer cells(9) and macrovascular (human umbilical vein, HUVECs) endothelial cells(10). A new protocol to characterize polymeric nanoparticles utilizing nanoparticle tracking analysis (NTA) is described. In this approach, both the particle size distribution and the distribution of the number of plasmids per particle are obtained(11). In addition, a high-throughput 96-well plate transfection assay for rapid screening of the transfection efficacy of polymeric nanoparticles is presented. In this protocol, poly(beta-amino ester)s (PBAEs) are used as model polymers and human retinal endothelial cells (HRECs) are used as model human cells. This protocol can be easily adapted to evaluate any polymeric nanoparticle and any cell type of interest in a multi

Mechanical properties and cytocompatibility of carbon fibre reinforced nano-hydroxyapatite/polyamide66 ternary biocomposite.

PubMed

Zhang, Xuesong; Zhang, Yonggang; Zhang, Xuelian; Wang, Yan; Wang, Jiaqi; Lu, Ming; Li, Hong

2015-02-01

Fibre-reinforced composites with good strength and ductility as bone repair biomaterials have been attracting increasing attention in biomedical applications. In the present study, a novel ternary composite was prepared using carbon fibre (CF) to reinforce a nano-hydroxyapatite/polyamide66 composite (HA/PA). The interface and mechanical strength of the ternary composite (CF/HA/PA) were characterised. In addition, to assess the cytocompatibility, the composite was co-cultured with MG-63 cells, and the cell morphology, MTT, and ALP were tested. The results indicated that CFs were uniformly distributed in the HA/PA matrix with random orientation and that the CFs bonded well to the HA/PA matrix. The reinforced ternary composite exhibited a compressive strength of 116-212 MPa, a bending strength of 89-138 MPa, a tensile strength of 109-181 MPa, with the breaking elongation ratio of 6.2-9.1%, and a tensile modulus of 2.9-5.8 GPa, with the values varying with increasing CF content from 5 to 20 (mass fraction). The MG-63 cells of normal phenotype were well extended and spread onto the ternary composite surface. In addition, its proliferation and differentiation on the composite surface were significantly increased with time, indicating that the incorporation of CFs into HA/PA had little negative effects on MG-63 cells. The incorporation of CFs into a HA/PA66 composite improved the strength and ductility and introduced no negative effects on the cytocompatibility. Hence, the CF/HA/PA ternary composite has potential to be used as a bone repair materials and in fixation devices. Copyright © 2014 Elsevier Ltd. All rights reserved.

The effects of nanostructured hydroxyapatite coating on the biodegradation and cytocompatibility of magnesium implants.

PubMed

Iskandar, Maria Emil; Aslani, Arash; Liu, Huinan

2013-08-01

Magnesium (Mg) alloys, a novel class of degradable, metallic biomaterials, have attracted growing interest as a promising alternative for medical implant and device applications due to their advantageous mechanical and biological properties. Although its biodegradability is an attractive property, rapid degradation of Mg in the physiological environments imposes a major obstacle that limits the translation of Mg-based implants to clinical applications. Therefore, the objective of this study was to develop a nanostructured hydroxyapatite (nHA) coating on polished Mg substrates to mediate the rapid degradation of Mg while improving its integration with bone tissue for orthopedic applications. The nHA coatings were deposited on polished Mg using the patented transonic particle acceleration (Spire Biomedical) process. Surface morphology, elemental compositions, and crystal structures were characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction (XRD) analysis, respectively. The degradation of nHA-coated and non-coated Mg samples was investigated by incubating the samples in phosphate buffered saline and revised simulated body fluid, under standard cell culture conditions. Rat bone marrow stromal cells (BMSCs) were harvested and cultured with nHA-coated and non-coated Mg samples to determine cytocompatibility. The degradation results suggested that the nHA coatings decreased Mg degradation. Improved BMSC adhesion was observed on the surfaces of the nHA-coated and non-coated Mg samples, in comparison with the cells on the culture plate surrounding the Mg samples. In conclusion, nHA coatings showed promise for improving the biodegradation and cytocompatibility properties of Mg-based orthopedic implants and should be further studied. Copyright © 2013 Wiley Periodicals, Inc.

Mechanical, degradation and cytocompatibility properties of magnesium coated phosphate glass fibre reinforced polycaprolactone composites.

PubMed

Liu, Xiaoling; Hasan, Muhammad S; Grant, David M; Harper, Lee T; Parsons, Andrew J; Palmer, Graham; Rudd, Chris D; Ahmed, Ifty

2014-11-01

Retention of mechanical properties of phosphate glass fibre reinforced degradable polyesters such as polycaprolactone and polylactic acid in aqueous media has been shown to be strongly influenced by the integrity of the fibre/polymer interface. A previous study utilising 'single fibre' fragmentation tests found that coating with magnesium improved the fibre and matrix interfacial shear strength. Therefore, the aim of this study was to investigate the effects of a magnesium coating on the manufacture and characterisation of a random chopped fibre reinforced polycaprolactone composite. Short chopped strand non-woven phosphate glass fibre mats were sputter coated with degradable magnesium to manufacture phosphate glass fibre/polycaprolactone composites. The degradation behaviour (water uptake, mass loss and pH change of the media) of these polycaprolactone composites as well as of pure polycaprolactone was investigated in phosphate buffered saline. The Mg coated fibre reinforced composites revealed less water uptake and mass loss during degradation compared to the non-coated composites. The cations released were also explored and a lower ion release profile for all three cations investigated (namely Na(+), Mg(2+) and Ca(2+)) was seen for the Mg coated composite samples. An increase of 17% in tensile strength and 47% in tensile modulus was obtained for the Mg coated composite samples. Both flexural and tensile properties were investigated and a higher retention of mechanical properties was obtained for the Mg coated fibre reinforced composite samples up to 10 days immersion in PBS. Cytocompatibility study showed both composite samples (coated and non-coated) had good cytocompatibility with human osteosarcoma cell line. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Bioinspired Ultratough Hydrogel with Fast Recovery, Self-Healing, Injectability and Cytocompatibility.

PubMed

Azevedo, Sara; Costa, Ana M S; Andersen, Amanda; Choi, Insung S; Birkedal, Henrik; Mano, João F

2017-07-01

Inspired by the mussel byssus adhesiveness, a highly hydrated polymeric structure is designed to combine, for the first time, a set of interesting features for load-bearing purposes. These characteristics include: i) a compressive strength and stiffness in the MPa range, ii) toughness and the ability to recover it upon successive cyclic loading, iii) the ability to quickly self-heal upon rupture, iv) the possibility of administration through minimally invasive techniques, such as by injection, v) the swelling ratio being adjusted to space-filling applications, and vi) cytocompatibility. Owing to these characteristics and the mild conditions employed, the encapsulation of very unstable and sensitive cargoes is possible, highlighting their potential to researchers in the biomedical field for the repair of load-bearing soft tissues, or to be used as an encapsulation platform for a variety of biological applications such as disease models for drug screening and therapies in a more realistic mechanical environment. Moreover, given the simplicity of this methodology and the enhanced mechanical performance, this strategy can be expanded to applications in other fields, such as agriculture and electronics. As such, it is anticipated that the proposed strategy will constitute a new, versatile, and cost-effective tool to produce engineered polymeric structures for both science and technology. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structure and Hydration of Highly-Branched, Monodisperse Phytoglycogen Nanoparticles

DOE PAGES

Nickels, Jonathan D.; Atkinson, John; Papp-Szabo, Erzsebet; ...

2016-01-30

Phytoglycogen is a naturally occurring polysaccharide nanoparticle made up of extensively branched glucose monomers. It has a number of unusual and advantageous properties, such as high water retention, low viscosity, and high stability in water, which make this biomaterial a promising candidate for a wide variety of applications. For this paper, we have characterized the structure and hydration of aqueous dispersions of phytoglycogen nanoparticles using neutron scattering. Small angle neutron scattering results suggest that the phytoglycogen nanoparticles behave similar to hard sphere colloids and are hydrated by a large number of water molecules (each nanoparticle contains between 250% and 285%more » of its mass in water). This suggests that phytoglycogen is an ideal sample in which to study the dynamics of hydration water. To this end, we used quasielastic neutron scattering (QENS) to provide an independent and consistent measure of the hydration number, and to estimate the retardation factor (or degree of water slow-down) for hydration water translational motions. These data demonstrate a length-scale dependence in the measured retardation factors that clarifies the origin of discrepancies between retardation factor values reported for hydration water using different experimental techniques. Finally, the present approach can be generalized to other systems containing nanoconfined water.« less

In-situ high-pressure x-ray diffraction study of zinc ferrite nanoparticles

DOE PAGES

Ferrari, S.; Kumar, R. S.; Grinblat, F.; ...

2016-04-23

We have studied the high-pressure structural behavior of zinc ferrite (ZnFe 2O 4) nanoparticles by powder X-ray diffraction measurements up to 47 GPa. We found that the cubic spinel structure of ZnFe 2O 4 remains up to 33 GPa and a phase transition is induced beyond this pressure. The high-pressure phase is indexed to an orthorhombic CaMn 2O 4-type structure. Upon decompression the low- and high-pressure phases coexist. The compressibility of both structures was also investigated. We have observed that the lattice parameters of the high-pressure phase behave anisotropically upon compression. Further, we predict possible phase transition around 55 GPa.more » For comparison, we also studied the compression behavior of magnetite (Fe 3O 4) nanoparticles by X-ray diffraction up to 23 GPa. Spinel-type ZnFe 2O 4 and Fe 3O 4 nanoparticles have a bulk modulus of 172 (20) GPa and 152 (9) GPa, respectively. Lastly, this indicates that in both cases the nanoparticles do not undergo a Hall-Petch strengthening.« less

In-situ high-pressure x-ray diffraction study of zinc ferrite nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferrari, S.; Kumar, R. S.; Grinblat, F.

We have studied the high-pressure structural behavior of zinc ferrite (ZnFe 2O 4) nanoparticles by powder X-ray diffraction measurements up to 47 GPa. We found that the cubic spinel structure of ZnFe 2O 4 remains up to 33 GPa and a phase transition is induced beyond this pressure. The high-pressure phase is indexed to an orthorhombic CaMn 2O 4-type structure. Upon decompression the low- and high-pressure phases coexist. The compressibility of both structures was also investigated. We have observed that the lattice parameters of the high-pressure phase behave anisotropically upon compression. Further, we predict possible phase transition around 55 GPa.more » For comparison, we also studied the compression behavior of magnetite (Fe 3O 4) nanoparticles by X-ray diffraction up to 23 GPa. Spinel-type ZnFe 2O 4 and Fe 3O 4 nanoparticles have a bulk modulus of 172 (20) GPa and 152 (9) GPa, respectively. Lastly, this indicates that in both cases the nanoparticles do not undergo a Hall-Petch strengthening.« less

Dry-air-stable lithium silicide-lithium oxide core-shell nanoparticles as high-capacity prelithiation reagents.

PubMed

Zhao, Jie; Lu, Zhenda; Liu, Nian; Lee, Hyun-Wook; McDowell, Matthew T; Cui, Yi

2014-10-03

Rapid progress has been made in realizing battery electrode materials with high capacity and long-term cyclability in the past decade. However, low first-cycle Coulombic efficiency as a result of the formation of a solid electrolyte interphase and Li trapping at the anodes, remains unresolved. Here we report LixSi-Li2O core-shell nanoparticles as an excellent prelithiation reagent with high specific capacity to compensate the first-cycle capacity loss. These nanoparticles are produced via a one-step thermal alloying process. LixSi-Li2O core-shell nanoparticles are processible in a slurry and exhibit high capacity under dry-air conditions with the protection of a Li2O passivation shell, indicating that these nanoparticles are potentially compatible with industrial battery fabrication processes. Both Si and graphite anodes are successfully prelithiated with these nanoparticles to achieve high first-cycle Coulombic efficiencies of 94% to >100%. The LixSi-Li2O core-shell nanoparticles enable the practical implementation of high-performance electrode materials in lithium-ion batteries.

High-performance iron oxide nanoparticles for magnetic particle imaging - guided hyperthermia (hMPI)

NASA Astrophysics Data System (ADS)

Bauer, Lisa M.; Situ, Shu F.; Griswold, Mark A.; Samia, Anna Cristina S.

2016-06-01

Magnetic particle imaging (MPI) is an emerging imaging modality that allows the direct and quantitative mapping of iron oxide nanoparticles. In MPI, the development of tailored iron oxide nanoparticle tracers is paramount to achieving high sensitivity and good spatial resolution. To date, most MPI tracers being developed for potential clinical applications are based on spherical undoped magnetite nanoparticles. For the first time, we report on the systematic investigation of the effects of changes in chemical composition and shape anisotropy on the MPI performance of iron oxide nanoparticle tracers. We observed a 2-fold enhancement in MPI signal through selective doping of magnetite nanoparticles with zinc. Moreover, we demonstrated focused magnetic hyperthermia heating by adapting the field gradient used in MPI. By saturating the iron oxide nanoparticles outside of a field free region (FFR) with an external static field, we can selectively heat a target region in our test sample. By comparing zinc-doped magnetite cubic nanoparticles with undoped spherical nanoparticles, we could show a 5-fold improvement in the specific absorption rate (SAR) in magnetic hyperthermia while providing good MPI signal, thereby demonstrating the potential for high-performance focused hyperthermia therapy through an MPI-guided approach (hMPI).Magnetic particle imaging (MPI) is an emerging imaging modality that allows the direct and quantitative mapping of iron oxide nanoparticles. In MPI, the development of tailored iron oxide nanoparticle tracers is paramount to achieving high sensitivity and good spatial resolution. To date, most MPI tracers being developed for potential clinical applications are based on spherical undoped magnetite nanoparticles. For the first time, we report on the systematic investigation of the effects of changes in chemical composition and shape anisotropy on the MPI performance of iron oxide nanoparticle tracers. We observed a 2-fold enhancement in MPI signal

High-Z Nanoparticle/Polymer Nanocomposites for Gamma-Ray Scintillation Detectors

NASA Astrophysics Data System (ADS)

Liu, Chao

An affordable and reliable solution for spectroscopic gamma-ray detection has long been sought after due to the needs from research, defense, and medical applications. Scintillators resolve gamma energy by proportionally converting a single high-energy photon into a number of photomultiplier-tube-detectable low-energy photons, which is considered a more affordable solution for general purposes compared to the delicate semiconductor detectors. An ideal scintillator should simultaneously exhibit the following characteristics: 1) high atomic number (Z) for high gamma stopping power and photoelectron production; 2) high light yield since the energy resolution is inversely proportional to the square root of light yield; 3) short emission decay lifetime; and 4) low cost and scalable production. However, commercial scintillators made from either inorganic single crystals or plastics fail to satisfy all requirements due to their intrinsic material properties and fabrication limitations. The concept of adding high-Z constituents into plastic scintillators to harness high Z, low cost, and fast emission in the resulting nanocomposite scintillators is not new in and of itself. Attempts have been made by adding organometallics, quantum dots, and scintillation nanocrystals into the plastic matrix. High-Z organometallics have long been used to improve the Z of plastic scintillators; however, their strong spin-orbit coupling effect entails careful triplet energy matching using expensive triplet emitters to avoid severe quenching of the light yield. On the other hand, reported quantum dot- and nanocrystal-polymer nanocomposites suffer from moderate Z and high optical loss due to aggregation and self-absorption at loadings higher than 10 wt%, limiting their potential for practical application. This dissertation strives to improve the performance of nanoparticle-based nanocomposite scintillators. One focus is to synthesize transparent nanocomposites with higher loadings of high

The Possibility of Using Composite Nanoparticles in High Energy Materials

NASA Astrophysics Data System (ADS)

Komarova, M. V.; Vorozhtsov, A. B.; Wakutin, A. G.

2017-01-01

The effect of nanopowders on the burning rate varying with the metal content in mixtures of different high energy composition is investigated. Experiments were performed on compositions based on an active tetrazol binder and electroexplosive nanoaluminum with addition of copper, nickel, or iron nanopowders, and of Al-Ni, Al-Cu, or Al-Fe composite nanoparticles produced by electrical explosion of heterogeneous metal wires. The results obtained from thermogravimetric analysis of model metal-based compositions are presented. The advantages of the composite nanoparticles and the possibility of using them in high energy materials are discussed.

Cytocompatible chitosan-graft-mPEG-based 5-fluorouracil-loaded polymeric nanoparticles for tumor-targeted drug delivery.

PubMed

Antoniraj, M Gover; Ayyavu, Mahesh; Henry, Linda Jeeva Kumari; Nageshwar Rao, Goutham; Natesan, Subramanian; Sundar, D Sathish; Kandasamy, Ruckmani

2018-03-01

Biodegradable materials like chitosan (CH) and methoxy polyethylene glycol (mPEG) are widely being used as drug delivery carriers for various therapeutic applications. In this study, copolymer (CH-g-mPEG) of CH and carboxylic acid terminated mPEG was synthesized by carbodiimide-mediated acid amine reaction. The resultant hydrophilic copolymer was characterized by Fourier transform infrared spectroscopy and 1 H NMR studies, revealing its relevant functional bands and proton peaks, respectively. Blank polymeric nanoparticles (B-PNPs) and 5-fluorouracil loaded polymeric nanoparticles (5-FU-PNPs) were formulated by ionic gelation method. Furthermore, folic acid functionalized FA-PNPs and FA-5-FU-PNPs were prepared for folate receptor-targeted drug delivery. FA-5-FU-PNPs were characterized by particle size, zeta potential, and in vitro drug release studies, resulting in 197.7 nm, +29.9 mv, and sustained drug release of 88% in 24 h, respectively. Cytotoxicity studies were performed for FA-PNPs and FA-5-FU-PNPs in MCF-7 cell line, which exhibited a cell viability of 80 and 41%, respectively. In vitro internalization studies were carried out for 5-FU-PNPs and FA-5-FU-PNPs which demonstrated increased cellular uptake of FA-5-FU-PNPs by receptor-mediated transport. Significant (p < .01) reduction (1.5-fold) of reactive oxygen species (ROS) accumulation was observed in lipopolysaccharides-stimulated RAW264.7 macrophages, revealing its potent antioxidant property. From the obtained results, it is concluded that folic acid functionalization of 5-FU-PNPs is an ideal approach for sustained and targeted drug delivery, thereby influencing better therapeutic effect.

Efficacy of ferulic acid encapsulated chitosan nanoparticles against Candida albicans biofilm.

PubMed

Panwar, Richa; Pemmaraju, Suma C; Sharma, Asvene K; Pruthi, Vikas

2016-06-01

Candida albicans, an opportunistic fungal pathogen is a major causative agent of superficial to systemic life-threating biofilm infections on indwelling medical devices. These biofilms acts as double edge swords owing to their resistance towards antibiotics and immunological barriers. To overcome this threat ferulic acid encapsulated chitosan nanoparticles (FA-CSNPs) were formulated to assess its efficacy as an antibiofilm agent against C. albicans. These FA-CSNPs were synthesized using ionotropic gelation method and observed through field emission scanning electron microscopy (FESEM) and fluorescent microscopy. Assessment of successful encapsulation and stability of ferulic acid into chitosan nanoparticles was made using Fourier transform infrared spectrum (FTIR), (1)H NMR and thermal analyses. Synthesized FA-CSNPs, were found to be cytocompatible, when tested using Human Embryonic Kidney (HEK-293) cell lines. XTT assay revealed that FA-CSNPs reduced the cell metabolic activity of C. albicans upto 22.5% as compared to native ferulic acid (63%) and unloaded CSNPs (88%) after 24 h incubation. Disruption of C. albicans biofilm architecture was visualized by FESEM. Results highlighted the potential of FA-CSNPs to be used as an effective alternative to the conventional antifungal therapeutics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Smart Porous Silicon Nanoparticles with Polymeric Coatings for Sequential Combination Therapy.

PubMed

Xu, Wujun; Thapa, Rinez; Liu, Dongfei; Nissinen, Tuomo; Granroth, Sari; Närvänen, Ale; Suvanto, Mika; Santos, Hélder A; Lehto, Vesa-Pekka

2015-11-02

In spite of the advances in drug delivery, the preparation of smart nanocomposites capable of precisely controlled release of multiple drugs for sequential combination therapy is still challenging. Here, a novel drug delivery nanocomposite was prepared by coating porous silicon (PSi) nanoparticles with poly(beta-amino ester) (PAE) and Pluronic F-127, respectively. Two anticancer drugs, doxorubicin (DOX) and paclitaxel (PTX), were separately loaded into the core of PSi and the shell of F127. The nanocomposite displayed enhanced colloidal stability and good cytocompatibility. Moreover, a spatiotemporal drug release was achieved for sequential combination therapy by precisely controlling the release kinetics of the two tested drugs. The release of PTX and DOX occurred in a time-staggered manner; PTX was released much faster and earlier than DOX at pH 7.0. The grafted PAE on the external surface of PSi acted as a pH-responsive nanovalve for the site-specific release of DOX. In vitro cytotoxicity tests demonstrated that the DOX and PTX coloaded nanoparticles exhibited a better synergistic effect than the free drugs in inducing cellular apoptosis. Therefore, the present study demonstrates a promising strategy to enhance the efficiency of combination cancer therapies by precisely controlling the release kinetics of different drugs.

Multiplexed highly sensitive detections of cancer biomarkers in thermal space using encapsulated phase change nanoparticles

NASA Astrophysics Data System (ADS)

Ma, Liyuan; Hong, Yan; Ma, Zeyu; Kaittanis, Charalambos; Perez, J. Manuel; Su, Ming

2009-07-01

We describe a multiplexed highly sensitive method to detect cancer biomarkers using silica encapsulated phase change nanoparticles as thermal barcodes. During phase changes, nanoparticles absorb heat energy without much temperature rise and show sharp melting peaks (0.6 °C). A series of phase change nanoparticles of metals or alloys can be synthesized in such a way that they melt between 100 and 700 °C, thus the multiplicity could reach 1000. The method has high sensitivity (8 nM) that can be enhanced using materials with large latent heat, nanoparticles with large diameter, or reducing the grafting density of biomolecules on nanoparticles.

Enhanced corrosion resistance and cytocompatibility of biodegradable Mg alloys by introduction of Mg(OH)2 particles into poly (L-lactic acid) coating

PubMed Central

Shi, Yong-juan; Pei, Jia; Zhang, Jian; Niu, Jia-lin; Zhang, Hua; Guo, Sheng-rong; Li, Zhong-hua; Yuan, Guang-yin

2017-01-01

A strategy of suppressing the fast degradation behaviour of Mg-based biomaterials by the introduction of one of Mg degradation products Mg(OH)2 was proposed according to the following degradation mechanism, Mg + 2H2O ⇋ Mg(OH)2 + H2↑. Specifically, Mg(OH)2 submicron particles were mixed into poly (L-lactic acid) (PLLA) to synthesize a composite coating onto hydrofluoric acid-pretreated Mg-Nd-Zn-Zr alloy. The in vitro degradation investigations showed that the addition of Mg(OH)2 particles not only slowed down the corrosion of Mg matrix, but also retarded the formation of gas pockets underneath the polymer coating. Correspondingly, cytocompatibility results exhibited significant improvement of proliferation of endothelial cells, and further insights was gained into the mechanisms how the introduction of Mg(OH)2 particles into PLLA coating affected the magnesium alloy degradation and cytocompatibility. The present study provided a promising surface modification strategy to tailor the degradation behaviour of Mg-based biomaterials. PMID:28150751

Bioactivity, cytocompatibility and thermal properties of experimental Bioglass-reinforced composites as potential root-canal filling materials.

PubMed

Alhashimi, Raghad Abdulrazzaq; Mannocci, Francesco; Sauro, Salvatore

2017-05-01

To evaluate the bioactivity and the cytocompatibility of experimental Bioglass-reinforced polyethylene-based root-canal filling materials. The thermal properties of the experimental materials were also evaluated using differential scanning calorimetry, while their radiopacity was assessed using a grey-scale value (GSV) aluminium step wedge and a phosphor plate digital system. Bioglass 45S5 (BAG), polyethylene and Strontium oxide (SrO) were used to create tailored composite fibres. The filler distribution within the composites was assessed using SEM, while their bioactivity was evaluated through infrared spectroscopy (FTIR) after storage in simulated body fluid (SBF). The radiopacity of the composite fibres and their thermal properties were determined using differential scanning calorimetry (DSC). The cytocompatibility of the experimental composites used in this study was assessed using human osteoblasts and statistically analysed using the Pairwise t-test (p<0.05). Bioglass and SrO fillers were well distributed within the resin matrix and increased both the thermal properties and the radiopacity of the polyethylene matrix. The FTIR showed a clear formation of calcium-phosphates, while, MTT and AlamrBlue tests demonstrated no deleterious effects on the metabolic activity of the osteoblast-like cells. BAG-reinforced polyethylene composites may be suitable as obturation materials for endodontic treatment. Since their low melting temperature, such innovative composites may be easily removed in case of root canal retreatment. Moreover, their biocompatibility and bioactivity may benefit proliferation of human osteoblast cells at the periapical area of the root. Copyright © 2017 Elsevier Ltd. All rights reserved.

3D Printing of Cytocompatible Water-Based Light-Cured Polyurethane with Hyaluronic Acid for Cartilage Tissue Engineering Applications

PubMed Central

Shie, Ming-You; Chang, Wen-Ching; Wei, Li-Ju; Huang, Yu-Hsin; Chen, Chien-Han; Shih, Cheng-Ting; Chen, Yi-Wen; Shen, Yu-Fang

2017-01-01

Diseases in articular cartilages have affected millions of people globally. Although the biochemical and cellular composition of articular cartilages is relatively simple, there is a limitation in the self-repair ability of the cartilage. Therefore, developing strategies for cartilage repair is very important. Here, we report on a new liquid resin preparation process of water-based polyurethane based photosensitive materials with hyaluronic acid with application of the materials for 3D printed customized cartilage scaffolds. The scaffold has high cytocompatibility and is one that closely mimics the mechanical properties of articular cartilages. It is suitable for culturing human Wharton’s jelly mesenchymal stem cells (hWJMSCs) and the cells in this case showed an excellent chondrogenic differentiation capacity. We consider that the 3D printing hybrid scaffolds may have potential in customized tissue engineering and also facilitate the development of cartilage tissue engineering. PMID:28772498

Reactor for tracking catalyst nanoparticles in liquid at high temperature under a high-pressure gas phase with X-ray absorption spectroscopy.

PubMed

Nguyen, Luan; Tao, Franklin Feng

2018-02-01

Structure of catalyst nanoparticles dispersed in liquid phase at high temperature under gas phase of reactant(s) at higher pressure (≥5 bars) is important for fundamental understanding of catalytic reactions performed on these catalyst nanoparticles. Most structural characterizations of a catalyst performing catalysis in liquid at high temperature under gas phase at high pressure were performed in an ex situ condition in terms of characterizations before or after catalysis since, from technical point of view, access to the catalyst nanoparticles during catalysis in liquid phase at high temperature under high pressure reactant gas is challenging. Here we designed a reactor which allows us to perform structural characterization using X-ray absorption spectroscopy including X-ray absorption near edge structure spectroscopy and extended X-ray absorption fine structure spectroscopy to study catalyst nanoparticles under harsh catalysis conditions in terms of liquid up to 350 °C under gas phase with a pressure up to 50 bars. This reactor remains nanoparticles of a catalyst homogeneously dispersed in liquid during catalysis and X-ray absorption spectroscopy characterization.

Decorating an individual living cell with a shell of controllable thickness by cytocompatible surface initiated graft polymerization.

PubMed

Wang, Guan; Zhang, Kai; Wang, Yindian; Zhao, Changwen; He, Bin; Ma, Yuhong; Yang, Wantai

2018-05-03

Surface engineering of individual living cells is a promising field for cell-based applications. However, engineering individual cells with controllable thickness by chemical methods has been rarely studied. This article describes the development of a new cytocompatible chemical strategy to decorate individual living cells. The thicknesses of the crosslinked shells could be conveniently controlled by the irradiation time, visible light intensity, or monomer concentration. Moreover, the lag phase of the yeast cell division was extended and their stability against lysis was improved, which could also be tuned by controlling the shell thickness.

Highly monodisperse multiple twinned AuCu-Pt trimetallic nanoparticles with high index surfaces.

PubMed

Khanal, Subarna; Bhattarai, Nabraj; McMaster, David; Bahena, Daniel; Velazquez-Salazar, J Jesus; Jose-Yacaman, Miguel

2014-08-14

Trimetallic nanoparticles possess different properties than their mono- and bi-metallic counterparts, opening a wide range of possibilities for diverse potential applications with the notion to study possible morphology, atomic ordering, reduce precious metal consumption and many others. In this paper, we present a comprehensive experimental study on AuCu-Pt trimetallic nanoparticles with an average diameter of 15 ± 1.0 nm, synthesized in a one-pot synthesis method and characterized by the Cs-corrected scanning transmission electron microscopy technique that allowed us to probe the structure at the atomic level resolution. A new way to control the nanoparticle morphology by the presence of third metal (Pt) is also discussed by the overgrowth of Pt on the as prepared AuCu core by Frank-van der Merwe (FM) layer-by-layer and Stranski-Krastanov (SK) island-on-wetting-layer growth modes. With the application of this research, we are now a step closer to produce optimum catalysts in which the active phase forms only surface monolayers. In addition, the nanoalloy exhibits high index facet surfaces with {211} and {321} families that are highly open-structure surfaces and are interesting for the catalytic applications.

Highly Monodisperse Multiple Twinned AuCu/Pt Trimetallic Nanoparticles with High Index Surfaces

PubMed Central

Khanal, Subarna; Bhattarai, Nabraj; McMaster, David; Bahena, Daniel; Velazquez-Salazar, J. Jesus

2014-01-01

Trimetallic nanoparticles present different properties than their mono- and bi-metallic counterparts, opening a wide range of possibilities for diverse potential applications with the notion to study possible morphology, atomic ordering, reduce precious metal consumption and many others. In this paper, we are presenting a comprehensive experimental study on AuCu/Pt trimetallic nanoparticles with an average diameter 15 ± 1.0 nm, synthesized in one-pot synthesis method and characterized by Cs-corrected scanning transmission electron microscopy technique that allowed us to probe the structure at the atomic level resolution. A new way to control the nanoparticle morphology by the presence of third metal (Pt) is also discussed by the overgrowth of Pt on as prepared AuCu core by Frank–van der Merwe (FM) layer-by-layer and Stranski–Krastanov (SK) island-on-wetting-layer growth modes. With the application of this research, we are now a step closer to produce optimum catalysts in which the active phase forms only surface monolayers. In addition, the nanoalloy presents high index facet surfaces with {211} and {321} families, that are highly open-structure surfaces and are interesting for the catalytic applications. PMID:24975090

Development of a highly transparent superamphiphobic plastic sheet by nanoparticle and chemical coating.

PubMed

Wong, Ten It; Wang, Hao; Wang, Fuke; Sin, Sau Leng; Quan, Cheng Gen; Wang, Shi Jie; Zhou, Xiaodong

2016-04-01

A highly transparent superamphiphobic plastic sheet was developed. The plastic sheet polymethyl methacrylate (PMMA) was spin-coated on a glass substrate. Synthesized silica nanoparticles were sprayed on PMMA, followed by fluorosilane drop-coating. The results of contact angle measurements show that the developed PMMA sheet has superamphiphobic properties with high advancing contact angles for water (154°), toluene (139°), and silicone oil (132.9°). The amphiphobicity of the plastic sheet can be tuned by the surface coverage of the silica nanoparticles distributed on the PMMA surface. The surface coverage of the nanoparticles on our PMMA sheet is about 20%, and it agrees with our contact angle calculations for the sheet with and without nanoparticles. Copyright © 2016 Elsevier Inc. All rights reserved.

Room Temperature Synthesis of Highly Monodisperse and Sers-Active Glucose-Reduced Gold Nanoparticles

NASA Astrophysics Data System (ADS)

Boitor, R. A.; Tódor, I. Sz.; Leopold, L. F.; Leopold, N.

2015-07-01

A novel method of synthesizing gold nanoparticles was developed through which glucose-coated nanospheres of high monodispersity were synthesized at room temperature. More than 85% of the nanoparticles showed a mean diameter of 8-9 nm. The nanoparticles were characterized through TEM, UV-Vis absorption spectroscopy, dynamic light scattering (DLS), and Zeta potential measurements and were found to be highly stable in colloidal form over time with a surface potential of -38.7 mV. The nanoparticles also showed a great Raman enhancing factor when they were tested as a surface-enhanced Raman scattering (SERS) substrate on various analytes such as rhodamine 6G, crystal violet chloride, cresyl violet chloride, rose bengal, and the Cu(II) 4-(2-pyridylazo)resorcinol complex at micromolar concentrations.

A highly sensitive and selective diagnostic assay based on virus nanoparticles

NASA Astrophysics Data System (ADS)

Park, Jin-Seung; Cho, Moon Kyu; Lee, Eun Jung; Ahn, Keum-Young; Lee, Kyung Eun; Jung, Jae Hun; Cho, Yunjung; Han, Sung-Sik; Kim, Young Keun; Lee, Jeewon

2009-04-01

Early detection of the protein marker troponin I in patients with a higher risk of acute myocardial infarction can reduce the risk of death from heart attacks. Most troponin assays are currently based on the conventional enzyme linked immunosorbent assay and have detection limits in the nano- and picomolar range. Here, we show that by combining viral nanoparticles, which are engineered to have dual affinity for troponin antibodies and nickel, with three-dimensional nanostructures including nickel nanohairs, we can detect troponin levels in human serum samples that are six to seven orders of magnitude lower than those detectable using conventional enzyme linked immunosorbent assays. The viral nanoparticle helps to orient the antibodies for maximum capture of the troponin markers. High densities of antibodies on the surfaces of the nanoparticles and nanohairs lead to greater binding of the troponin markers, which significantly enhances detection sensitivities. The nickel nanohairs are re-useable and can reproducibly differentiate healthy serum from unhealthy ones. We expect other viral nanoparticles to form similar highly sensitive diagnostic assays for a variety of other protein markers.

Antibacterial Activity of Ciprofloxacin-Encapsulated Cockle Shells Calcium Carbonate (Aragonite) Nanoparticles and Its Biocompatability in Macrophage J774A.1

PubMed Central

Isa, Tijani; Zakaria, Zuki Abu Bakar; Rukayadi, Yaya; Mohd Hezmee, Mohd Noor; Jaji, Alhaji Zubair; Imam, Mustapha Umar; Hammadi, Nahidah Ibrahim; Mahmood, Saffanah Khuder

2016-01-01

The use of nanoparticle delivery systems to enhance intracellular penetration of antibiotics and their retention time is becoming popular. The challenge, however, is that the interaction of nanoparticles with biological systems at the cellular level must be established prior to biomedical applications. Ciprofloxacin–cockle shells-derived calcium carbonate (aragonite) nanoparticles (C-CSCCAN) were developed and characterized. Antibacterial activity was determined using a modified disc diffusion protocol on Salmonella Typhimurium (S. Typhimurium). Biocompatibilittes with macrophage were evaluated using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 5-Bromo-2′-deoxyuridine (BrdU) assays. Transcriptional regulation of interleukin 1 beta (IL-1β) was determined using reverse transcriptase-polymerase chain reaction (RT-PCR). C-CSCCAN were spherical in shape, with particle sizes ranging from 11.93 to 22.12 nm. Encapsulation efficiency (EE) and loading content (LC) were 99.5% and 5.9%, respectively, with negative ζ potential. X-ray diffraction patterns revealed strong crystallizations and purity in the formulations. The mean diameter of inhibition zone was 18.6 ± 0.5 mm, which was better than ciprofloxacin alone (11.7 ± 0.9 mm). Study of biocompatability established the cytocompatability of the delivery system without upregulation of IL-1β. The results indicated that ciprofloxacin–nanoparticles enhanced the antibacterial efficacy of the antibiotic, and could act as a suitable delivery system against intracellular infections. PMID:27213349

Antibacterial Activity of Ciprofloxacin-Encapsulated Cockle Shells Calcium Carbonate (Aragonite) Nanoparticles and Its Biocompatability in Macrophage J774A.1.

PubMed

Isa, Tijani; Zakaria, Zuki Abu Bakar; Rukayadi, Yaya; Mohd Hezmee, Mohd Noor; Jaji, Alhaji Zubair; Imam, Mustapha Umar; Hammadi, Nahidah Ibrahim; Mahmood, Saffanah Khuder

2016-05-19

The use of nanoparticle delivery systems to enhance intracellular penetration of antibiotics and their retention time is becoming popular. The challenge, however, is that the interaction of nanoparticles with biological systems at the cellular level must be established prior to biomedical applications. Ciprofloxacin-cockle shells-derived calcium carbonate (aragonite) nanoparticles (C-CSCCAN) were developed and characterized. Antibacterial activity was determined using a modified disc diffusion protocol on Salmonella Typhimurium (S. Typhimurium). Biocompatibilittes with macrophage were evaluated using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 5-Bromo-2'-deoxyuridine (BrdU) assays. Transcriptional regulation of interleukin 1 beta (IL-1β) was determined using reverse transcriptase-polymerase chain reaction (RT-PCR). C-CSCCAN were spherical in shape, with particle sizes ranging from 11.93 to 22.12 nm. Encapsulation efficiency (EE) and loading content (LC) were 99.5% and 5.9%, respectively, with negative ζ potential. X-ray diffraction patterns revealed strong crystallizations and purity in the formulations. The mean diameter of inhibition zone was 18.6 ± 0.5 mm, which was better than ciprofloxacin alone (11.7 ± 0.9 mm). Study of biocompatability established the cytocompatability of the delivery system without upregulation of IL-1β. The results indicated that ciprofloxacin-nanoparticles enhanced the antibacterial efficacy of the antibiotic, and could act as a suitable delivery system against intracellular infections.

High efficiency protein separation with organosilane assembled silica coated magnetic nanoparticles

NASA Astrophysics Data System (ADS)

Chang, Jeong Ho; Kang, Ki Ho; Choi, Jinsub; Jeong, Young Keun

2008-10-01

This work describes the development of high efficiency protein separation with functionalized organosilanes on the surface of silica coated magnetic nanoparticles. The magnetic nanoparticles were synthesized with average particle size of 9 nm and silica coated magnetic nanoparticles were obtained by controlling the coating thicknesses on magnetic nanoparticles. The silica coating thickness could be uniformly sized with a diameter of 10-40 nm by a sol-gel approach. The surface modification was performed with four kinds of functionalized organosilanes such as carboxyl, aldehyde, amine, and thiol groups. The protein separation work with organosilane assembled silica coated magnetic nanoparticles was achieved for model proteins such as bovine serum albumin (BSA) and lysozyme (LSZ) at different pH conditions. Among the various functionalities, the thiol group showed good separation efficiency due to the change of electrostatic interactions and protein conformational structure. The adsorption efficiency of BSA and LSZ was up to 74% and 90% corresponding pH 4.65 and pH 11.

Sodium hydroxide catalyzed monodispersed high surface area silica nanoparticles.

PubMed

Bhakta, Snehasis; Dixit, Chandra K; Bist, Itti; Jalil, Karim Abdel; Suib, Steven L; Rusling, James F

2016-07-01

Understanding of the synthesis kinetics and our ability to modulate medium conditions allowed us to generate nanoparticles via an ultra-fast process. The synthesis medium is kept quite simple with tetraethyl orthosilicate (TEOS) as precursor and 50% ethanol and sodium hydroxide catalyst. Synthesis is performed under gentle conditions at 20 °C for 20 min Long synthesis time and catalyst-associated drawbacks are most crucial in silica nanoparticle synthesis. We have addressed both these bottlenecks by replacing the conventional Stober catalyst, ammonium hydroxide, with sodium hydroxide. We have reduced the overall synthesis time from 20 to 1/3 h, ~60-fold decrease, and obtained highly monodispersed nanoparticles with 5-fold higher surface area than Stober particles. We have demonstrated that the developed NPs with ~3-fold higher silane can be used as efficient probes for biosensor applications.

Characterization and anticancer potential of ferulic acid-loaded chitosan nanoparticles against ME-180 human cervical cancer cell lines

NASA Astrophysics Data System (ADS)

Panwar, Richa; Sharma, Asvene K.; Kaloti, Mandeep; Dutt, Dharm; Pruthi, Vikas

2016-08-01

Ferulic acid (FA) is a widely distributed hydroxycinnamic acid found in various cereals and fruits exhibiting potent antioxidant and anticancer activities. However, due to low solubility and permeability, its availability to biological systems is limited. Non-toxic chitosan-tripolyphosphate pentasodium (CS-TPP) nanoparticles (NPs) are used to load sparingly soluble molecules and drugs, increasing their bioavailability. In the present work, we have encapsulated FA into the CS-TPP NPs to increase its potential as a therapeutic agent. Different concentrations of FA were tested to obtain optimum sized FA-loaded CS-TPP nanoparticles (FA/CS-TPP NPs) by ionic gelation method. Nanoparticles were characterized by scanning electron microscopy, Fourier transformation infrared spectroscopy (FTIR), thermogravimetric analyses and evaluated for their anticancer activity against ME-180 human cervical cancer cell lines. The FTIR spectra confirmed the encapsulation of FA and thermal analysis depicted its degradation profile. A concentration-dependent relationship between FA encapsulation efficiency and FA/CS-TPP NPs diameter was observed. Smooth and spherical FA-loaded cytocompatible nanoparticles with an average diameter of 125 nm were obtained at 40 µM FA conc. The cytotoxicity of 40 µM FA/CS-TPP NPs against ME-180 cervical cancer cell lines was found to be higher as compared to 40 µM native FA. Apoptotic morphological changes as cytoplasmic remnants and damaged wrinkled cells in ME-180 cells were visualized using scanning electron microscopic and fluorescent microscopic techniques. Data concluded that chitosan enveloped FA nanoparticles could be exploited as an excellent therapeutic drug against cancer cells proliferation.

Facile and green synthesis of highly stable L-cysteine functionalized copper nanoparticles

NASA Astrophysics Data System (ADS)

Kumar, Nikhil; Upadhyay, Lata Sheo Bachan

2016-11-01

A simple eco-friendly method for L-cysteine capped copper nanoparticles (CCNPs) synthesis in aqueous solution has been developed. Glucose and L-cysteine were used as reducing agent and capping/functionalizing agent, respectively. Different parameters such as capping agent concentration, pH, reaction temperature, and reducing agent concentration were optimized during the synthesis. The L-cysteine capped copper nanoparticle were characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, Particle size and zeta potential analyser, and high resolution transmission electron microscopy. Spherical shaped cysteine functionalized/capped copper nanoparticles with an average size of 40 nm were found to be highly stable at room temperature (RT) for a period of 1 month

Length-dependent corrosion behavior, Ni2+ release, cytocompatibility, and antibacterial ability of Ni-Ti-O nanopores anodically grown on biomedical NiTi alloy.

PubMed

Hang, Ruiqiang; Liu, Yanlian; Bai, Long; Zhang, Xiangyu; Huang, Xiaobo; Jia, Husheng; Tang, Bin

2018-08-01

In the present work, nickel-titanium-oxygen nanopores with different length (0.55-114 μm) were anodically grown on nearly equiatomic nickel-titanium (NiTi) alloy. Length-dependent corrosion behavior, nickel ion (Ni 2+ ) release, cytocompatibility, and antibacterial ability were investigated by electrochemical, analytical chemistry, and biological methods. The results show constructing nanoporous structure on the NiTi alloy improve its corrosion resistance. However, the anodized samples release more Ni 2+ than that of the bare NiTi alloy, suggesting chemical dissolution of the nanopores rather than electrochemical corrosion governs the Ni 2+ release. In addition, the Ni 2+ release amount increases with nanopore length. The anodized samples show good cytocompatibility when the nanopore length is <11 μm. Encouragingly, the length scale covers the one (1-11 μm) that the nanopores showing favorable antibacterial ability. Consequently, the nanopores with length in the range of 1-11 μm are promising as coatings of biomedical NiTi alloy for anti-infection, drug delivery, and other desirable applications. Copyright © 2018 Elsevier B.V. All rights reserved.

Generation of drugs coated iron nanoparticles through high energy ball milling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radhika Devi, A.; Murty, B. S.; Chelvane, J. A.

The iron nanoparticles coated with oleic acid and drugs such as folic acid/Amoxicillin were synthesized by high energy ball milling and characterized by X-ray diffraction, Transmission electron microscope, zeta potential, dynamic light scattering, Fourier Transform Infra red (FT-IR) measurements, and thermo gravimetric analysis (TGA). FT-IR and TGA measurements show good adsorption of drugs on oleic acid coated nanoparticles. Magnetic measurements indicate that saturation magnetization is larger for amoxicillin coated particles compared to folic acid coated particles. The biocompatibility of the magnetic nanoparticles prepared was evaluated by in vitro cytotoxicity assay using L929 cells as model cells.

Construction of poly(lactic-co-glycolic acid)/ZnO nanorods/Ag nanoparticles hybrid coating on Ti implants for enhanced antibacterial activity and biocompatibility.

PubMed

Xiang, Yiming; Li, Jun; Liu, Xiangmei; Cui, Zhenduo; Yang, Xianjin; Yeung, K W K; Pan, Haobo; Wu, Shuilin

2017-10-01

Poly(lactic-co-glycolic acid)/Ag/ZnO nanorods coating were successfully prepared on the surface of Ti metallic implants using a hydrothermal method and subsequent spin-coating of mixtures of poly(lactic-co-glycolic acid) and silver nanoparticles. The poly(lactic-co-glycolic acid)/Ag/ZnO nanorods coating exhibited excellent antibacterial efficacy of over 96% against both Staphylococcus aureus and Escherichia coli when the initial content of Ag nanoparticles was over 3wt%. In addition, the release of both silver and zinc could last for over a hundred days due to the enwrapping of poly(lactic-co-glycolic acid). Proliferation of mouse calvarial cells exhibited minimal cytotoxicity on the poly(lactic-co-glycolic acid)/Ag/ZnO coating with an initial content of Ag nanoparticles of 1wt% and 3wt%, while it inhibited cell proliferation once this value was increased to 6wt%. The results revealed that this poly(lactic-co-glycolic acid)/Ag/ZnO composite could provide a long-lasting antibacterial approach and good cytocompatibility, thus exhibiting considerable potential for biomedical application in orthopedic and dental implants with excellent self-antibacterial activity and good biocompatibility. Copyright © 2017 Elsevier B.V. All rights reserved.

High polarization of nuclear spins mediated by nanoparticles at millikelvin temperatures.

PubMed

Owers-Bradley, John R; Horsewill, Anthony J; Peat, David T; Goh, Kelvin S K; Gadian, David G

2013-07-07

Nuclear magnetic resonance (NMR) techniques are extensively used in many areas of basic and clinical research, as well as in diagnostic medicine. However, NMR signals are intrinsically weak, and this imposes substantial constraints on the amounts and concentrations of materials that can be detected. The signals are weak because of the low energies characteristic of NMR and the resulting very low (typically 0.0001-0.01%) polarization of the nuclear spins. Here, we show that exposure to very low temperatures and high magnetic fields, in conjunction with nanoparticle-mediated relaxation enhancement, can be used to generate extremely high nuclear polarization levels on a realistic timescale; with copper nanoparticles at 15 mK and 14 T, (13)C polarization grew towards its equilibrium level of 23% with an estimated half-time of about 60 hours. This contrasts with a (13)C half-time of at least one year in the presence of aluminium nanoparticles. Cupric oxide nanoparticles were also effective relaxation agents. Our findings lead us to suspect that the relaxation may be mediated, at least in part, by the remarkable magnetic properties that some nanoparticle preparations can display. This methodology offers prospects for achieving polarization levels of 10-50% or more for many nuclear species, with a wide range of potential applications in structural biology and medicine.

Synthesis and characterization of Nd3+: Yb3+ co-doped near infrared sensitive fluorapatite nanoparticles as a bioimaging probe

NASA Astrophysics Data System (ADS)

Karthi, S.; Kumar, G. A.; Sardar, D. K.; Santhosh, C.; Girija, E. K.

2018-03-01

Trivalent Nd and Yb co-doped rod shaped hexagonal phase fluorapatite (FAP) nanoparticles of length and width about 32 and 13 nm, respectively were prepared by hydrothermal method and investigated the ability for 980 nm emission via Nd3+ → Yb3+ energy transfer with the objective of utilizing them in biomedical imaging. Nd3+ → Yb3+ energy transfer in FAP was studied as a function of both Nd3+ and Yb3+ concentrations and found that when Yb3+ concentration was 10 mol% the FAP phase has partially turned in to YbPO4 phase. The Yb3+ emission intensity at 980 nm significantly increased up to 5 mol% Yb3+ doping and then reduced drastically for further increase in its concentration. Nd3+ →Yb3+ energy transfer rates were evaluated from the decay curves and found that a transfer rate of 71% for 2 mol% Nd3+ co-doped with 5 mol% Yb3+. The cytocompatibility test with fibroblast like cells using MTT assay revealed that the nanoparticles are compatible with the cells.

Preparation of uniform nanoparticles of ultra-high purity metal oxides, mixed metal oxides, metals, and metal alloys

DOEpatents

Woodfield, Brian F.; Liu, Shengfeng; Boerio-Goates, Juliana; Liu, Qingyuan; Smith, Stacey Janel

2012-07-03

In preferred embodiments, metal nanoparticles, mixed-metal (alloy) nanoparticles, metal oxide nanoparticles and mixed-metal oxide nanoparticles are provided. According to embodiments, the nanoparticles may possess narrow size distributions and high purities. In certain preferred embodiments, methods of preparing metal nanoparticles, mixed-metal nanoparticles, metal oxide nanoparticles and mixed-metal nanoparticles are provided. These methods may provide tight control of particle size, size distribution, and oxidation state. Other preferred embodiments relate to a precursor material that may be used to form nanoparticles. In addition, products prepared from such nanoparticles are disclosed.

Influence of the Microstructure and Silver Content on Degradation, Cytocompatibility, and Antibacterial Properties of Magnesium-Silver Alloys In Vitro

PubMed Central

Schade, Ronald; Rothe, Holger; Müller, Sören; Liefeith, Klaus

2017-01-01

Implantation is a frequent procedure in orthopedic surgery, particularly in the aging population. However, it possesses the risk of infection and biofilm formation at the surgical site. This can cause unnecessary suffering to patients and burden on the healthcare system. Pure Mg, as a promising metal for biodegradable orthopedic implants, exhibits some antibacterial effects due to the alkaline pH produced during degradation. However, this antibacterial effect may not be sufficient in a dynamic environment, for example, the human body. The aim of this study was to increase the antibacterial properties under harsh and dynamic conditions by alloying silver metal with pure Mg as much as possible. Meanwhile, the Mg-Ag alloys should not show obvious cytotoxicity to human primary osteoblasts. Therefore, we studied the influence of the microstructure and the silver content on the degradation behavior, cytocompatibility, and antibacterial properties of Mg-Ag alloys in vitro. The results indicated that a higher silver content can increase the degradation rate of Mg-Ag alloys. However, the degradation rate could be reduced by eliminating the precipitates in the Mg-Ag alloys via T4 treatment. By controlling the microstructure and increasing the silver content, Mg-Ag alloys obtained good antibacterial properties in harsh and dynamic conditions but had almost equivalent cytocompatibility to human primary osteoblasts as pure Mg. PMID:28717409

Influence of the Microstructure and Silver Content on Degradation, Cytocompatibility, and Antibacterial Properties of Magnesium-Silver Alloys In Vitro.

PubMed

Liu, Zhidan; Schade, Ronald; Luthringer, Bérengère; Hort, Norbert; Rothe, Holger; Müller, Sören; Liefeith, Klaus; Willumeit-Römer, Regine; Feyerabend, Frank

2017-01-01

Implantation is a frequent procedure in orthopedic surgery, particularly in the aging population. However, it possesses the risk of infection and biofilm formation at the surgical site. This can cause unnecessary suffering to patients and burden on the healthcare system. Pure Mg, as a promising metal for biodegradable orthopedic implants, exhibits some antibacterial effects due to the alkaline pH produced during degradation. However, this antibacterial effect may not be sufficient in a dynamic environment, for example, the human body. The aim of this study was to increase the antibacterial properties under harsh and dynamic conditions by alloying silver metal with pure Mg as much as possible. Meanwhile, the Mg-Ag alloys should not show obvious cytotoxicity to human primary osteoblasts. Therefore, we studied the influence of the microstructure and the silver content on the degradation behavior, cytocompatibility, and antibacterial properties of Mg-Ag alloys in vitro. The results indicated that a higher silver content can increase the degradation rate of Mg-Ag alloys. However, the degradation rate could be reduced by eliminating the precipitates in the Mg-Ag alloys via T4 treatment. By controlling the microstructure and increasing the silver content, Mg-Ag alloys obtained good antibacterial properties in harsh and dynamic conditions but had almost equivalent cytocompatibility to human primary osteoblasts as pure Mg.

High-speed collision of copper nanoparticle with aluminum surface: Molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Pogorelko, Victor V.; Mayer, Alexander E.; Krasnikov, Vasiliy S.

2016-12-01

We investigate the effect of the high-speed collision of copper nanoparticles with aluminum surface by means of molecular dynamic simulations. Studied diameter of nanoparticles is varied within the range 7.2-22 nm and the velocity of impact is equal to 500 or 1000 m/s. Dislocation analysis shows that a large quantity of dislocations is formed within the impact area. Overall length of dislocations is determined, first of all, by the impact velocity and by the size of incident copper nanoparticle, in other words, by the kinetic energy of the nanoparticle. Dislocations occupy the total volume of the impacted aluminum single crystal layer (40.5 nm in thickness) in the form of intertwined structure in the case of large kinetic energy of the incident nanoparticle. Decrease in the initial kinetic energy or increase in the layer thickness lead to restriction of the penetration depth of the dislocation net; formation of separate dislocation loops is observed in this case. Increase in the initial system temperature slightly raises the dislocation density inside the bombarded layer and considerably decreases the dislocation density inside the nanoparticle. The temperature increase also leads to a deeper penetration of the copper atoms inside the aluminum. Additional molecular dynamic simulations show that the deposited particles demonstrate a very good adhesion even in the case of the considered relatively large nanoparticles. Medium energy of the nanoparticles corresponding to velocity of about 500 m/s and elevated temperature of the system about 700-900 K are optimal parameters for production of high-quality layers of copper on the aluminum surface. These conditions provide both a good adhesion and a less degree of the plastic deformation. At the same time, higher impact velocities can be used for combined treatment consisting of both the plastic deformation and the coating.

Enhanced cytocompatibility and reduced genotoxicity of polydimethylsiloxane modified by plasma immersion ion implantation.

PubMed

Tong, Liping; Zhou, Wenhua; Zhao, Yuetao; Yu, Xuefeng; Wang, Huaiyu; Chu, Paul K

2016-12-01

Polydimethylsiloxane(PDMS) is a common industrial polymer with advantages such as ease of fabrication, tunable hardness, and other desirable properties, but the basic (-OSi(CH 3 ) 2 -) n structure in PDMS is inherently hydrophobic thereby hampering application to biomedical engineering. In this study, plasma immersion ion implantation (PIII) is conducted on PDMS to improve the biological properties. PIII forms wrinkled "herringbone" patterns and abundant O-containing functional groups on PDMS to alter the surface hydrophilicity. The biocompatibility of the modified PDMS is assessed with Chinese hamster ovarian cells and compared to that of the untreated PDMS. Our results reveal that the PDMS samples after undergoing PIII have better cytocompatibility and lower genotoxicity. PIII which is a non-line-of-sight technique extends the application of PDMS to the biomedical field. Copyright © 2016 Elsevier B.V. All rights reserved.

Standards and Methodologies for Characterizing Radiobiological Impact of High-Z Nanoparticles

PubMed Central

Subiel, Anna; Ashmore, Reece; Schettino, Giuseppe

2016-01-01

Research on the application of high-Z nanoparticles (NPs) in cancer treatment and diagnosis has recently been the subject of growing interest, with much promise being shown with regards to a potential transition into clinical practice. In spite of numerous publications related to the development and application of nanoparticles for use with ionizing radiation, the literature is lacking coherent and systematic experimental approaches to fully evaluate the radiobiological effectiveness of NPs, validate mechanistic models and allow direct comparison of the studies undertaken by various research groups. The lack of standards and established methodology is commonly recognised as a major obstacle for the transition of innovative research ideas into clinical practice. This review provides a comprehensive overview of radiobiological techniques and quantification methods used in in vitro studies on high-Z nanoparticles and aims to provide recommendations for future standardization for NP-mediated radiation research. PMID:27446499

Targeted Delivery of Small Interfering RNA Using Reconstituted High-Density Lipoprotein Nanoparticles12

PubMed Central

Shahzad, Mian MK; Mangala, Lingegowda S; Han, Hee Dong; Lu, Chunhua; Bottsford-Miller, Justin; Nishimura, Masato; Mora, Edna M; Lee, Jeong-Won; Stone, Rebecca L; Pecot, Chad V; Thanapprapasr, Duangmani; Roh, Ju-Won; Gaur, Puja; Nair, Maya P; Park, Yun-Yong; Sabnis, Nirupama; Deavers, Michael T; Lee, Ju-Seog; Ellis, Lee M; Lopez-Berestein, Gabriel; McConathy, Walter J; Prokai, Laszlo; Lacko, Andras G; Sood, Anil K

2011-01-01

RNA interference holds tremendous potential as a therapeutic approach, especially in the treatment of malignant tumors. However, efficient and biocompatible delivery methods are needed for systemic delivery of small interfering RNA (siRNA). To maintain a high level of growth, tumor cells scavenge high-density lipoprotein (HDL) particles by overexpressing its receptor: scavenger receptor type B1 (SR-B1). In this study, we exploited this cellular characteristic to achieve efficient siRNA delivery and established a novel formulation of siRNA by incorporating it into reconstituted HDL (rHDL) nanoparticles. Here, we demonstrate that rHDL nanoparticles facilitate highly efficient systemic delivery of siRNA in vivo, mediated by the SR-B1. Moreover, in therapeutic proof-of-concept studies, these nanoparticles were effective in silencing the expression of two proteins that are key to cancer growth and metastasis (signal transducer and activator of transcription 3 and focal adhesion kinase) in orthotopic mouse models of ovarian and colorectal cancer. These data indicate that an rHDL nanoparticle is a novel and highly efficient siRNA carrier, and therefore, this novel technology could serve as the foundation for new cancer therapeutic approaches. PMID:21472135

High-Resolution Light Transmission Spectroscopy of Nanoparticles in Real Time

NASA Astrophysics Data System (ADS)

Tanner, Carol; Sun, Nan; Deatsch, Alison; Li, Frank; Ruggiero, Steven

2017-04-01

As implemented here, Light Transmission Spectroscopy (LTS) is a high-resolution real-time technique for eliminating spectral noise and systematic effects in wide band spectroscopic measurements of nanoparticles. In this work, we combine LTS with spectral inversion for the purpose of characterizing the size, shape, and number of nanoparticles in solution. The apparatus employs a wide-band multi-wavelength light source and grating spectrometers coupled to CCD detectors. The light source ranges from 210 to 2000 nm, and the wavelength dependent light detection system ranges from 200 to 1100 nm with <=1 nm resolution. With this system, nanoparticles ranging from 1 to 3000 nm diameters can be studied. The nanoparticles are typically suspended in pure water or water-based buffer solutions. For testing and calibration purposes, results are presented for nanoparticles composed of polystyrene and gold. Mie theory is used to model the total extinction cross-section, and spectral inversion is employed to obtain quantitative particle size distributions. Discussed are the precision, accuracy, resolution, and sensitivity of our results. The technique is quite versatile and can be applied to spectroscopic investigations where wideband, accurate, low-noise, real-time spectra are desired. University of Notre Dame Office of Research, College of Science, Department of Physics, and USDA.

Preparation & characterization of high purity Cu2 ZnSn(SxSe1-x)4 nanoparticles

NASA Astrophysics Data System (ADS)

Negash, Bethlehem G.

Research in thin film solar cells applies novel techniques to synthesize cost effective and highly efficient absorber materials in order to generate electricity directly from solar energy. Of these materials, copper zinc tin sulfoselenide (Cu2ZnSn(SxSe1-x) 4) nanoparticles have shown great promise in solar cell applications due to optimal material properties as well as low cost & relative abundance of materials.1,2 Sulfoselenide nanoparticles have also a broader impact in other industries including electronics3, LED 4, and biomedical research5. Of the many routes of manufacturing these class of semiconductors, colloidal synthesis of Cu 2ZnSn(SxSe1-x)4 offers a scalable, low cost and high-throughput route for manufacturing high efficiency thin-film solar cells. Hydrazine processed Cu2ZnSn(SxSe1-x )4 devices have reached a record power conversion efficiency (PCE) of 12.6%, much higher than the 9.6% reported for physical vapor deposition (PVD) systems.6,7. Despite high efficiencies, wet synthesis of nanoparticles, however, is made more complicated in multi-element, quaternary and quinary systems such as copper zinc tin sulfoselenide (CZTSSe) and copper indium gallium diselenide (CIGSe). One major disadvantage in these systems is growth of the desired quaternary or quinary phase in competition with unwanted binary and ternary phases with low energy of formation.8,9 Moreover, various reaction parameters such as reaction time, temperature, and choice of ligand also affect, chemical as well as physical properties of resulting nanoparticles. Understanding of the formation mechanisms of the particles is necessary in order to address some of these challenges in wet synthesis of CZTSSe nanoparticles. In this study, we investigate synthesis conditions & reaction parameters which yield high purity Cu2ZnSn(SxSe1-x) 4 nanoparticles as well as attempt to understand the growth mechanism of these nanoparticles. This was achieved by manipulating anion precursor preparation routes as

High-performance 3D printing of hydrogels by water-dispersible photoinitiator nanoparticles.

PubMed

Pawar, Amol A; Saada, Gabriel; Cooperstein, Ido; Larush, Liraz; Jackman, Joshua A; Tabaei, Seyed R; Cho, Nam-Joon; Magdassi, Shlomo

2016-04-01

In the absence of water-soluble photoinitiators with high absorbance in the ultraviolet (UV)-visible range, rapid three-dimensional (3D) printing of hydrogels for tissue engineering is challenging. A new approach enabling rapid 3D printing of hydrogels in aqueous solutions is presented on the basis of UV-curable inks containing nanoparticles of highly efficient but water-insoluble photoinitiators. The extinction coefficient of the new water-dispersible nanoparticles of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) is more than 300 times larger than the best and most used commercially available water-soluble photoinitiator. The TPO nanoparticles absorb significantly in the range from 385 to 420 nm, making them suitable for use in commercially available, low-cost, light-emitting diode-based 3D printers using digital light processing. The polymerization rate at this range is very fast and enables 3D printing that otherwise is impossible to perform without adding solvents. The TPO nanoparticles were prepared by rapid conversion of volatile microemulsions into water-dispersible powder, a process that can be used for a variety of photoinitiators. Such water-dispersible photoinitiator nanoparticles open many opportunities to enable rapid 3D printing of structures prepared in aqueous solutions while bringing environmental advantages by using low-energy curing systems and avoiding the need for solvents.

Antibacterial properties and cytocompatibility of tantalum oxide coatings with different silver content

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Heng-Li; Chang, Yin-Yu, E-mail: yinyu@mail2000.com.tw; Chen, Hung-Jui

Tantalum (Ta) oxides and their coatings have been proved to increase their applications in the biomedical fields by improving osseointegration and wear resistance. In this study, Ta oxide coatings containing different proportions of Ag are deposited on SS304 materials. A twin-gun magnetron sputtering system is used to deposit the tantalum oxide-Ag coating. In this study, Staphylococcus aureus, which exhibits physiological commensalism on the human skin, nares, and mucosal and oral areas, is chosen as the model for in vitro antibacterial analyses via a fluorescence staining method using Syto9. The cytocompatibility and adhesive morphology of human skin fibroblast cells (CCD-966SK) onmore » the coatings are also determined by using the microculture tetrazolium assay. This study shows that Ta{sub 2}O{sub 5} and Ta{sub 2}O{sub 5}-Ag coatings with 12.5 at. % of Ag exhibit improved antibacterial effects against S. aureus and have good skin fibroblast cell cellular biocompatibility.« less

High-throughput fabrication and screening improves gold nanoparticle chemiresistor sensor performance.

PubMed

Hubble, Lee J; Cooper, James S; Sosa-Pintos, Andrea; Kiiveri, Harri; Chow, Edith; Webster, Melissa S; Wieczorek, Lech; Raguse, Burkhard

2015-02-09

Chemiresistor sensor arrays are a promising technology to replace current laboratory-based analysis instrumentation, with the advantage of facile integration into portable, low-cost devices for in-field use. To increase the performance of chemiresistor sensor arrays a high-throughput fabrication and screening methodology was developed to assess different organothiol-functionalized gold nanoparticle chemiresistors. This high-throughput fabrication and testing methodology was implemented to screen a library consisting of 132 different organothiol compounds as capping agents for functionalized gold nanoparticle chemiresistor sensors. The methodology utilized an automated liquid handling workstation for the in situ functionalization of gold nanoparticle films and subsequent automated analyte testing of sensor arrays using a flow-injection analysis system. To test the methodology we focused on the discrimination and quantitation of benzene, toluene, ethylbenzene, p-xylene, and naphthalene (BTEXN) mixtures in water at low microgram per liter concentration levels. The high-throughput methodology identified a sensor array configuration consisting of a subset of organothiol-functionalized chemiresistors which in combination with random forests analysis was able to predict individual analyte concentrations with overall root-mean-square errors ranging between 8-17 μg/L for mixtures of BTEXN in water at the 100 μg/L concentration. The ability to use a simple sensor array system to quantitate BTEXN mixtures in water at the low μg/L concentration range has direct and significant implications to future environmental monitoring and reporting strategies. In addition, these results demonstrate the advantages of high-throughput screening to improve the performance of gold nanoparticle based chemiresistors for both new and existing applications.

Facile and high-efficient immobilization of histidine-tagged multimeric protein G on magnetic nanoparticles

NASA Astrophysics Data System (ADS)

Lee, Jiho; Chang, Jeong Ho

2014-12-01

This work reports the high-efficient and one-step immobilization of multimeric protein G on magnetic nanoparticles. The histidine-tagged (His-tag) recombinant multimeric protein G was overexpressed in Escherichia coli BL21 by the repeated linking of protein G monomers with a flexible linker. High-efficient immobilization on magnetic nanoparticles was demonstrated by two different preparation methods through the amino-silane and chloro-silane functionalization on silica-coated magnetic nanoparticles. Three kinds of multimeric protein G such as His-tag monomer, dimer, and trimer were tested for immobilization efficiency. For these tests, bicinchoninic acid (BCA) assay was employed to determine the amount of immobilized His-tag multimeric protein G. The result showed that the immobilization efficiency of the His-tag multimeric protein G of the monomer, dimer, and trimer was increased with the use of chloro-silane-functionalized magnetic nanoparticles in the range of 98% to 99%, rather than the use of amino-silane-functionalized magnetic nanoparticles in the range of 55% to 77%, respectively.

Double-hydrophobic elastin-like polypeptides with added functional motifs: Self-assembly and cytocompatibility.

PubMed

Le, Duc H T; Tsutsui, Yoko; Sugawara-Narutaki, Ayae; Yukawa, Hiroshi; Baba, Yoshinobu; Ohtsuki, Chikara

2017-09-01

We have recently developed a novel double-hydrophobic elastin-like triblock polypeptide called GPG, designed after the uneven distribution of two different hydrophobic domains found in elastin, an extracellular matrix protein providing elasticity and resilience to tissues. Upon temperature trigger, GPG undergoes a sequential self-assembling process to form flexible beaded nanofibers with high homogeneity and excellent dispersibility in water. Given that GPG might be a potential elastin-mimetic material, we sought to explore the biological activities of this block polypeptide. Besides GPG, several functionalized derivatives were also constructed by fusing functional motifs such as KAAK or KAAKGRGDS at the C-terminal of GPG. Although the added motifs affected the kinetics of fiber formation and β-sheet contents, all three GPGs assembled into beaded nanofibers at the physiological temperature. The resulting GPG nanofibers preserved their beaded structures in cell culture medium; therefore, they were coated on polystyrene substrates to study their cytocompatibility toward mouse embryonic fibroblasts, NIH-3T3. Among the three polypeptides, GPG having the cell-binding motif GRGDS derived from fibronectin showed excellent cell adhesion and cell proliferation properties compared to other conventional materials, suggesting its promising applications as extracellular matrices for mammalian cells. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2475-2484, 2017. © 2017 Wiley Periodicals, Inc.

Preparation of highly fluorescent magnetic nanoparticles for analytes-enrichment and subsequent biodetection.

PubMed

Zhang, Bingbo; Chen, Bingdi; Wang, Yilong; Guo, Fangfang; Li, Zhuoquan; Shi, Donglu

2011-01-15

Bifunctional nanoparticles with highly fluorescence and decent magnetic properties have been widely used in biomedical application. In this study, highly fluorescent magnetic nanoparticles (FMNPs) with uniform size of ca. 40 nm are prepared by encapsulation of both magnetic nanoparticles (MNPs) and shell/core quantum dots (QDs) with well-designed shell structure/compositions into silica matrix via a one-pot reverse microemulsion approach. The spectral analysis shows that the FMNPs hold high fluorescent quantum yield (QY). The QYs and saturation magnetization of the FMNPs can be regulated by varying the ratio of the encapsulated QDs to MNPs. Moreover, the surface of the FMNPs can be modified to offer chemical groups for antibody conjugation for following use in target-enrichment and subsequent fluorescent detection. The in vitro immunofluorescence assay and flow cytometric analysis indicate that the bifunctional FMNPs-antibody bioconjugates are capable of target-enrichment, magnetic separation and can also be used as alternative fluorescent probes on flow cytometry for biodetection. Copyright © 2010 Elsevier Inc. All rights reserved.

Extraordinarily high conductivity of flexible adhesive films by hybrids of silver nanoparticle-nanowires

NASA Astrophysics Data System (ADS)

Muhammed Ajmal, C.; Mol Menamparambath, Mini; Ryeol Choi, Hyouk; Baik, Seunghyun

2016-06-01

Highly conductive flexible adhesive (CFA) film was developed using micro-sized silver flakes (primary fillers), hybrids of silver nanoparticle-nanowires (secondary fillers) and nitrile butadiene rubber. The hybrids of silver nanoparticle-nanowires were synthesized by decorating silver nanowires with silver nanoparticle clusters using bifunctional cysteamine as a linker. The dispersion in ethanol was excellent for several months. Silver nanowires constructed electrical networks between the micro-scale silver flakes. The low-temperature surface sintering of silver nanoparticles enabled effective joining of silver nanowires to silver flakes. The hybrids of silver nanoparticle-nanowires provided a greater maximum conductivity (54 390 S cm-1) than pure silver nanowires, pure multiwalled carbon nanotubes, and multiwalled carbon nanotubes decorated with silver nanoparticles in nitrile butadiene rubber matrix. The resistance change was smallest upon bending when the hybrids of silver nanoparticle-nanowires were employed. The adhesion of the film on polyethylene terephthalate substrate was excellent. Light emitting diodes were successfully wired to the CFA circuit patterned by the screen printing method for application demonstration.

Fabrication of novel cryomill for synthesis of high purity metallic nanoparticles

NASA Astrophysics Data System (ADS)

Kumar, Nirmal; Biswas, Krishanu

2015-08-01

The successful preparation of free standing metal nanoparticles with high purity in bulk quantity is the pre-requisite for any potential application. This is possible by using ball milling at cryogenic temperature. However, the most of ball mills available in the market do not allow preparing high purity metal nanoparticles by this route. In addition, it is not possible to carry out in situ measurements of process parameters as well as diagnostic of the process. In the present investigation, we present a detailed study on the fabrication of a cryomill, which is capable of avoiding contaminations in the product. It also provides in situ measurements and diagnostic of the low temperature milling process. Online monitoring of the milling temperature and observation of ball motion are the important aspects in the newly designed mill. The nanoparticles prepared using this fabricated mill have been found to be free standing and also free from contaminations.

Electrochemical synthesis of elongated noble metal nanoparticles, such as nanowires and nanorods, on high-surface area carbon supports

DOEpatents

Adzic, Radoslav; Blyznakov, Stoyan; Vukmirovic, Miomir

2015-08-04

Elongated noble-metal nanoparticles and methods for their manufacture are disclosed. The method involves the formation of a plurality of elongated noble-metal nanoparticles by electrochemical deposition of the noble metal on a high surface area carbon support, such as carbon nanoparticles. Prior to electrochemical deposition, the carbon support may be functionalized by oxidation, thus making the manufacturing process simple and cost-effective. The generated elongated nanoparticles are covalently bound to the carbon support and can be used directly in electrocatalysis. The process provides elongated noble-metal nanoparticles with high catalytic activities and improved durability in combination with high catalyst utilization since the nanoparticles are deposited and covalently bound to the carbon support in their final position and will not change in forming an electrode assembly.

High-performance 3D printing of hydrogels by water-dispersible photoinitiator nanoparticles

PubMed Central

Pawar, Amol A.; Saada, Gabriel; Cooperstein, Ido; Larush, Liraz; Jackman, Joshua A.; Tabaei, Seyed R.; Cho, Nam-Joon; Magdassi, Shlomo

2016-01-01

In the absence of water-soluble photoinitiators with high absorbance in the ultraviolet (UV)–visible range, rapid three-dimensional (3D) printing of hydrogels for tissue engineering is challenging. A new approach enabling rapid 3D printing of hydrogels in aqueous solutions is presented on the basis of UV-curable inks containing nanoparticles of highly efficient but water-insoluble photoinitiators. The extinction coefficient of the new water-dispersible nanoparticles of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) is more than 300 times larger than the best and most used commercially available water-soluble photoinitiator. The TPO nanoparticles absorb significantly in the range from 385 to 420 nm, making them suitable for use in commercially available, low-cost, light-emitting diode–based 3D printers using digital light processing. The polymerization rate at this range is very fast and enables 3D printing that otherwise is impossible to perform without adding solvents. The TPO nanoparticles were prepared by rapid conversion of volatile microemulsions into water-dispersible powder, a process that can be used for a variety of photoinitiators. Such water-dispersible photoinitiator nanoparticles open many opportunities to enable rapid 3D printing of structures prepared in aqueous solutions while bringing environmental advantages by using low-energy curing systems and avoiding the need for solvents. PMID:27051877

Facile synthesis of ultrafine cobalt oxide nanoparticles for high-performance supercapacitors.

PubMed

Liu, Fangyan; Su, Hai; Jin, Long; Zhang, Haitao; Chu, Xiang; Yang, Weiqing

2017-11-01

The ultrafine Co 3 O 4 nanoparticles are successfully prepared by a novel solvothermal-precipitation approach which exploits the supernatant liquid of Co 3 O 4 nanoflake micropheres synthesized by solvothermal method before. Interestingly, the water is only employed to obtain the ultrafine nanoparticles in supernatant liquid which was usually thrown away before. The microstructure measurement results of the as-grown samples present the homogeneous disperse ultrafine Co 3 O 4 nanoparticles with the size of around 5-10nm. The corresponding synthesis mechanism of the ultrafine Co 3 O 4 nanoparticles is proposed. More importantly, these ultrafine Co 3 O 4 nanoparticles obtained at 250°C show the highest specific capacitance of 523.0Fg -1 at 0.5Ag -1 , 2.6 times that of Co 3 O 4 nanoflake micropheres due to the quantum size effect. Meanwhile, the sample annealed under 350°C possesses the best cycling stability with capacitance retention of 104.9% after 1500 cycles. These results unambiguously demonstrate that this work not only provides a novel, facile, and eco-friendly approach to prepare high-performance Co 3 O 4 nanoparticles electrode materials for supercapacitors but also develops a widely used method for the preparation of other materials on a large scale. Copyright © 2017 Elsevier Inc. All rights reserved.

The release kinetics, antimicrobial activity and cytocompatibility of differently prepared collagen/hydroxyapatite/vancomycin layers: Microstructure vs. nanostructure.

PubMed

Suchý, Tomáš; Šupová, Monika; Klapková, Eva; Adamková, Václava; Závora, Jan; Žaloudková, Margit; Rýglová, Šárka; Ballay, Rastislav; Denk, František; Pokorný, Marek; Sauerová, Pavla; Hubálek Kalbáčová, Marie; Horný, Lukáš; Veselý, Jan; Voňavková, Tereza; Průša, Richard

2017-03-30

The aim of this study was to develop an osteo-inductive resorbable layer allowing the controlled elution of antibiotics to be used as a bone/implant bioactive interface particularly in the case of prosthetic joint infections, or as a preventative procedure with respect to primary joint replacement at a potentially infected site. An evaluation was performed of the vancomycin release kinetics, antimicrobial efficiency and cytocompatibility of collagen/hydroxyapatite layers containing vancomycin prepared employing different hydroxyapatite concentrations. Collagen layers with various levels of porosity and structure were prepared using three different methods: by means of the lyophilisation and electrospinning of dispersions with 0, 5 and 15wt% of hydroxyapatite and 10wt% of vancomycin, and by means of the electrospinning of dispersions with 0, 5 and 15wt% of hydroxyapatite followed by impregnation with 10wt% of vancomycin. The maximum concentration of the released active form of vancomycin characterised by means of HPLC was achieved via the vancomycin impregnation of the electrospun layers, whereas the lowest concentration was determined for those layers electrospun directly from a collagen solution containing vancomycin. Agar diffusion testing revealed that the electrospun impregnated layers exhibited the highest level of activity. It was determined that modification using hydroxyapatite exerts no strong effect on vancomycin evolution. All the tested samples exhibited sufficient cytocompatibility with no indication of cytotoxic effects using human osteoblastic cells in direct contact with the layers or in 24-hour infusions thereof. The results herein suggest that nano-structured collagen-hydroxyapatite layers impregnated with vancomycin following cross-linking provide suitable candidates for use as local drug delivery carriers. Copyright © 2017 Elsevier B.V. All rights reserved.

Fabrication of Highly Stable and Efficient PtCu Alloy Nanoparticles on Highly Porous Carbon for Direct Methanol Fuel Cells.

PubMed

Khan, Inayat Ali; Qian, Yuhong; Badshah, Amin; Zhao, Dan; Nadeem, Muhammad Arif

2016-08-17

Boosting the durability of Pt nanoparticles by controlling the composition and morphology is extremely important for fuel cells commercialization. We deposit the Pt-Cu alloy nanoparticles over high surface area carbon in different metallic molar ratios and optimize the conditions to achieve desired material. The novel bimetallic electro-catalyst {Pt-Cu/PC-950 (15:15%)} offers exceptional electrocatalytic activity when tested for both oxygen reduction reaction and methanol oxidation reactions. A high mass activity of 0.043 mA/μgPt (based on Pt mass) is recorded for ORR. An outstanding longevity of this electro-catalyst is noticed when compared to 20 wt % Pt loaded either on PC-950 or commercial carbon. The high surface area carbon support offers enhanced activity and prevents the nanoparticles from agglomeration, migration, and dissolution as evident by TEM analysis.

Next generation radiotherapy biomaterials loaded with high-Z nanoparticles

NASA Astrophysics Data System (ADS)

Cifter, Gizem

This research investigates the dosimetric feasibility of using high-Z nanoparticles as localized radiosensitizers to boost the dose to the residual tumor cells during accelerated partial breast irradiation while minimizing the dose to surrounding healthy tissue. Analytical microdosimetry calculations were carried out to calculate dose enhancement (DEF) in the presence of high-Z nanoparticles. It has been proposed that routinely used inert radiotherapy (RT) biomaterials (e.g. fiducials, spacers) can be upgraded to smarter ones by coating/loading them with radiosensitizing gold nanoparticles (GNPs), for sustained in-situ release after implantation to enhance RT. Prototype smart biomaterials were produced by incorporating the GNPs in poly (D,L-lactide-co-glycolide) (PLGA) polymer millirods during the gel phase of production. In vitro release of GNPs was monitored over time by optical/spectroscopy methods as a function of various design parameters. The prototype smart biomaterials displayed sustained customizable release of NPs in-vitro, reaching a burst release profile approximately after 25 days. The results also show that customizable release profiles can be achievable by varying GNP concentrations that are embedded within smart biomaterials, as well as other design parameters. This would potentially allow customizable local dose boost resulting in diverse treatment planning opportunities for individual cases. Considered together, the results provide preliminary data for development of next generation of RT biomaterials, which can be employed at no additional inconvenience to RT patients.

Ultra-high sensitivity imaging of cancer using SERRS nanoparticles

NASA Astrophysics Data System (ADS)

Kircher, Moritz F.

2016-05-01

"Surface-enhanced Raman spectroscopy" (SERS) nanoparticles have gained much attention in recent years for in silico, in vitro and in vivo sensing applications. Our group has developed novel generations of biocompatible "surfaceenhanced resonance Raman spectroscopy" (SERRS) nanoparticles as novel molecular imaging agents. Via rigorous optimization of the different variables contributing to the Raman enhancement, we were able to design SERRS nanoparticles with so far unprecedented sensitivity of detection under in vivo imaging conditions (femto-attomolar range). This has resulted in our ability to visualize, with a single nanoparticle, many different cancer types (after intravenous injection) in mouse models. The cancer types we have tested so far include brain, breast, esophagus, stomach, pancreas, colon, sarcoma, and prostate cancer. All mouse models used are state-of-the-art and closely mimic the tumor biology in their human counterparts. In these animals, we were able to visualize not only the bulk tumors, but importantly also microscopic extensions and locoregional satellite metastases, thus delineating for the first time the true extent of tumor spread. Moreover, the particles enable the detection of premalignant lesions. Given their inert composition they are expected to have a high chance for clinical translation, where we envision them to have an impact in various scenarios ranging from early detection, image-guidance in open or minimally invasive surgical procedures, to noninvasive imaging in conjunction with spatially offset (SESORS) Raman detection devices.

High Resolution Live Cell Raman Imaging Using Subcellular Organelle-Targeting SERS-Sensitive Gold Nanoparticles with Highly Narrow Intra-Nanogap

PubMed Central

Kang, Jeon Woong; So, Peter T. C.; Dasari, Ramachandra R.; Lim, Dong-Kwon

2015-01-01

We report a method to achieve high speed and high resolution live cell Raman images using small spherical gold nanoparticles with highly narrow intra-nanogap structures responding to NIR excitation (785 nm) and high-speed confocal Raman microscopy. The three different Raman-active molecules placed in the narrow intra-nanogap showed a strong and uniform Raman intensity in solution even under transient exposure time (10 ms) and low input power of incident laser (200 μW), which lead to obtain high-resolution single cell image within 30 s without inducing significant cell damage. The high resolution Raman image showed the distributions of gold nanoparticles for their targeted sites such as cytoplasm, mitochondria, or nucleus. The high speed Raman-based live cell imaging allowed us to monitor rapidly changing cell morphologies during cell death induced by the addition of highly toxic KCN solution to cells. These results strongly suggest that the use of SERS-active nanoparticle can greatly improve the current temporal resolution and image quality of Raman-based cell images enough to obtain the detailed cell dynamics and/or the responses of cells to potential drug molecules. PMID:25646716

Surface modification of titanium substrates with silver nanoparticles embedded sulfhydrylated chitosan/gelatin polyelectrolyte multilayer films for antibacterial application.

PubMed

Li, Wen; Xu, Dawei; Hu, Yan; Cai, Kaiyong; Lin, Yingcheng

2014-06-01

To develop Ti implants with potent antibacterial activity, a novel "sandwich-type" structure of sulfhydrylated chitosan (Chi-SH)/gelatin (Gel) polyelectrolyte multilayer films embedding silver (Ag) nanoparticles was coated onto titanium substrate using a spin-assisted layer-by-layer assembly technique. Ag ions would be enriched in the polyelectrolyte multilayer films via the specific interactions between Ag ions and -HS groups in Chi-HS, thus leading to the formation of Ag nanoparticles in situ by photo-catalytic reaction (ultraviolet irradiation). Contact angle measurement and field emission scanning electron microscopy equipped with energy dispersive X-ray spectroscopy were employed to monitor the construction of Ag-containing multilayer on titanium surface, respectively. The functional multilayered films on titanium substrate [Ti/PEI/(Gel/Chi-SH/Ag) n /Gel] could efficiently inhibit the growth and activity of Bacillus subtitles and Escherichia coli onto titanium surface. Moreover, studies in vitro confirmed that Ti substrates coating with functional multilayer films remained the biological functions of osteoblasts, which was reflected by cell morphology, cell viability and ALP activity measurements. This study provides a simple, versatile and generalized methodology to design functional titanium implants with good cyto-compatibility and antibacterial activity for potential clinical applications.

High capacity lithium ion batteries composed of cobalt oxide nanoparticle anodes and Raman spectroscopic analysis of nanoparticle strain dynamics in batteries

NASA Astrophysics Data System (ADS)

Islam, Mohammad A.; Zuba, Mateusz; DeBiase, Vincent; Noviasky, Nicholas; Hawley, Christopher J.

2018-02-01

Cobalt nanoparticle thin films were electrophoretically deposited on copper current collectors and were annealed into thin films of hollow Co3O4 nanoparticles. These thin films were directly used as the anodes of lithium ion batteries (LIBs) without the addition of conducting carbons and bonding agents. LIBs thus fabricated show high gravimetric capacities and long cycle lives. For ≈1.0 μm thick Co3O4 nanoparticle films the gravimetric capacities of the batteries were more than 800 mAh g-1 at a current rate of C/15, which is about 90% of the theoretical maximum. Additionally, the batteries were able to undergo 200 charge/discharge cycles at a relatively fast rate of C/5 and maintain 50% of the initial capacity. In order to understand the electrochemistry of lithiation in the context of nanoparticles, Raman spectra were collected at different stages of the electrode cycles to determine the chemical and structural changes in the nanomaterials. Our results indicate that initially the electrode nanoparticles were under significant strain and as the battery underwent many cycles of charging/discharging the nanoparticles experienced progressive strain relaxation.

Unconventional route to encapsulated ultrasmall gold nanoparticles for high-temperature catalysis.

PubMed

Zhang, Tingting; Zhao, Hongyu; He, Shengnan; Liu, Kai; Liu, Hongyang; Yin, Yadong; Gao, Chuanbo

2014-07-22

Ultrasmall gold nanoparticles (us-AuNPs, <3 nm) have been recently recognized as surprisingly active and extraordinarily effective green catalysts. Their stability against sintering during reactions, however, remains a serious issue for practical applications. Encapsulating such small nanoparticles in a layer of porous silica can dramatically enhance the stability, but it has been extremely difficult to achieve using conventional sol-gel coating methods due to the weak metal/oxide affinity. In this work, we address this challenge by developing an effective protocol for the synthesis of us-AuNP@SiO2 single-core/shell nanospheres. More specifically, we take an alternative route by starting with ultrasmall gold hydroxide nanoparticles, which have excellent affinity to silica, then carrying out controllable silica coating in reverse micelles, and finally converting gold hydroxide particles into well-protected us-AuNPs. With a single-core/shell configuration that prevents sintering of nearby us-AuNPs and amino group modification of the Au/SiO2 interface that provides additional coordinating interactions, the resulting us-AuNP@SiO2 nanospheres are highly stable at high temperatures and show high activity in catalytic CO oxidation reactions. A dramatic and continuous increase in the catalytic activity has been observed when the size of the us-AuNPs decreases from 2.3 to 1.5 nm, which reflects the intrinsic size effect of the Au nanoparticles on an inert support. The synthesis scheme described in this work is believed to be extendable to many other ultrasmall metal@oxide nanostructures for much broader catalytic applications.

High resolution SEM imaging of gold nanoparticles in cells and tissues.

PubMed

Goldstein, A; Soroka, Y; Frušić-Zlotkin, M; Popov, I; Kohen, R

2014-12-01

The growing demand of gold nanoparticles in medical applications increases the need for simple and efficient characterization methods of the interaction between the nanoparticles and biological systems. Due to its nanometre resolution, modern scanning electron microscopy (SEM) offers straightforward visualization of metallic nanoparticles down to a few nanometre size, almost without any special preparation step. However, visualization of biological materials in SEM requires complicated preparation procedure, which is typically finished by metal coating needed to decrease charging artefacts and quick radiation damage of biomaterials in the course of SEM imaging. The finest conductive metal coating available is usually composed of a few nanometre size clusters, which are almost identical to the metal nanoparticles employed in medical applications. Therefore, SEM monitoring of metal nanoparticles within cells and tissues is incompatible with the conventional preparation methods. In this work, we show that charging artefacts related to non-conductive biological specimen can be successfully eliminated by placing the uncoated biological sample on a conductive substrate. By growing the cells on glass pre-coated with a chromium layer, we were able to observe the uptake of 10 nm gold nanoparticles inside uncoated and unstained macrophages and keratinocytes cells. Imaging in back scattered electrons allowed observation of gold nanoparticles located inside the cells, while imaging in secondary electron gave information on gold nanoparticles located on the surface of the cells. By mounting a skin cross-section on an improved conductive holder, consisting of a silicon substrate coated with copper, we were able to observe penetration of gold nanoparticles of only 5 nm size through the skin barrier in an uncoated skin tissue. The described method offers a convenient modification in preparation procedure for biological samples to be analyzed in SEM. The method provides high

Production of High-Value Nanoparticles via Biogenic Processes Using Aquacultural and Horticultural Food Waste

PubMed Central

Ghosh, Purabi R.; Fawcett, Derek; Sharma, Shashi B.; Poinern, Gerrard E. J.

2017-01-01

The quantities of organic waste produced globally by aquacultural and horticulture are extremely large and offer an attractive renewable source of biomolecules and bioactive compounds. The availability of such large and diverse sources of waste materials creates a unique opportunity to develop new recycling and food waste utilisation strategies. The aim of this review is to report the current status of research in the emerging field of producing high-value nanoparticles from food waste. Eco-friendly biogenic processes are quite rapid, and are usually carried out at normal room temperature and pressure. These alternative clean technologies do not rely on the use of the toxic chemicals and solvents commonly associated with traditional nanoparticle manufacturing processes. The relatively small number of research articles in the field have been surveyed and evaluated. Among the diversity of waste types, promising candidates and their ability to produce various high-value nanoparticles are discussed. Experimental parameters, nanoparticle characteristics and potential applications for nanoparticles in pharmaceuticals and biomedical applications are discussed. In spite of the advantages, there are a number of challenges, including nanoparticle reproducibility and understanding the formation mechanisms between different food waste products. Thus, there is considerable scope and opportunity for further research in this emerging field. PMID:28773212

Formation mechanism, degradation behavior, and cytocompatibility of a nanorod-shaped HA and pore-sealed MgO bilayer coating on magnesium.

PubMed

Li, Bo; Han, Yong; Qi, Kai

2014-10-22

A novel bilayer coating (HT24h) was fabricated on magnesium using microarc oxidation (MAO) and hydrothermal treatment (HT). The coating comprises an outer layer of narrow interrod spaced hydroxyapatite (HA) nanorods and an inner layer of MgO containing Mg(OH)2/HA-sealing-pores. The hydrothermal formation mechanism of HA nanorods on MAO-formed MgO was explored. Also, evolution of structure and bonding integrity of HT24h coating with immersion in physiological saline (PS) for 0-90 days, corrosion resistance and cytocompatibility of the coating were investigated, together with MgO containing Mg(OH)2-sealing-pores (HT2h) and porous MgO (MAO) coatings. Corrosion resistance was identified by three-point bending and electrochemical tests in PS, while cytocompatibility was determined by MTT, live/dead staining, and vinculin-actin-nucleus tricolor staining assays of hFOB1.19 cells. Immersion tests indicate that cracking rather than delamination is a common feature in most areas of the coatings up to day 90 and degradation is the reason for thinning in thickness of the coatings. MAO and HT2h coatings exhibit a significant thinning due to fast degradation of MgO. However, HT24h coating shows a quite small thinning, owing to the fact that the HA nanorods underwent quite slow degradation while the underlying MgO only underwent conversion to Mg(OH)2 without dissolution of the Mg(OH)2. Scratch tests reveal that HT24h coating still retains relatively high bonding integrity, although the failure position changes from the MgO interior to a point between the HA and MgO layers after 90 days of immersion. HT24h coating appears far more effective than MAO and HT2h coatings in reducing degradation and maintaining the mechanical integrity of Mg, as well as enhancing the mitochondrial activity, adhesion, and proliferation of osteoblasts.

Comparing highly ordered monolayers of nanoparticles fabricated using electrophoretic deposition: Cobalt ferrite nanoparticles versus iron oxide nanoparticles

DOE PAGES

Dickerson, James H.; Krejci, Alex J.; Garcia, Adriana -Mendoza; ...

2015-08-01

Ordered assemblies of nanoparticles remain challenging to fabricate, yet could open the door to many potential applications of nanomaterials. Here, we demonstrate that locally ordered arrays of nanoparticles, using electrophoretic deposition, can be extended to produce long-range order among the constituents. Voronoi tessellations along with multiple statistical analyses show dramatic increases in order compared with previously reported assemblies formed through electric field-assisted assembly. As a result, based on subsequent physical measurements of the nanoparticles and the deposition system, the underlying mechanisms that generate increased order are inferred.

Development of functional nano-particle layer for highly efficient OLED

NASA Astrophysics Data System (ADS)

Lee, Jae-Hyun; Kim, Min-Hoi; Choi, Haechul; Choi, Yoonseuk

2015-12-01

Organic light emitting diodes (OLEDs) are now widely commercialized in market due to many advantages such as possibility of making thin or flexible devices. Nevertheless there are still several things to obtain the high quality flexible OLEDs, one of the most important issues is the light extraction of the device. It is known that OLEDs have the typical light loss such as the waveguide loss, plasmon absorption loss and internal total reflection. In this paper, we demonstrate the one-step processed light scattering films with aluminum oxide nano-particles and polystyrene matrix composite to achieve highly efficient OLEDs. Optical characteristics and surface roughness of light scattering film was optimized by changing the mixing concentration of Al2O3 nano-particles and investigated with the atomic force microscopy and hazemeter, respectively.

Interfacially Optimized, High Energy Density Nanoparticle-Polymer Composites for Capacitive Energy Storage

NASA Astrophysics Data System (ADS)

Shipman, Joshua; Riggs, Brian; Luo, Sijun; Adireddy, Shiva; Chrisey, Douglas

Energy storage is a green energy technology, however it must be cost effective and scalable to meet future energy demands. Polymer-nanoparticle composites are low cost and potentially offer high energy storage. This is based on the high breakdown strength of polymers and the high dielectric constant of ceramic nanoparticles, but the incoherent nature of the interface between the two components prevents the realization of their combined full potential. We have created inkjet printable nanoparticle-polymer composites that have mitigated many of these interface effects, guided by first principle modelling of the interface. We detail density functional theory modelling of the interface and how it has guided our use in in specific surface functionalizations and other inorganic layers. We have validated our approach by using finite element analysis of the interface. By choosing the correct surface functionalization we are able to create dipole traps which further increase the breakdown strength of our composites. Our nano-scale understanding has allowed us to create the highest energy density composites currently available (>40 J/cm3).

Fabrication, nanomechanical characterization, and cytocompatibility of gold-reinforced chitosan bio-nanocomposites

PubMed Central

Patel, Nimitt G.; Kumar, Ajeet; Jayawardana, Veroni N.; Woodworth, Craig D.; Yuya, Philip A.

2017-01-01

Chitosan, a naturally derived polymer represents one of the most technologically important classes of active materials with applications in a variety of industrial and biomedical fields. Gold nanoparticles (~32 nm) were synthesized via a citrate reduction method from chloroauric acid and incorporated in Chitosan matrix. Bio-nanocomposite films with varying concentrations of gold nanoparticles were prepared through solution casting process. Uniform distribution of gold nanoparticles was achieved throughout the chitosan matrix and was confirmed with SEM. Synthesis outcomes and prepared nanocomposites were characterized using SEM, TEM, EDX, SAED, UV–vis, XRD, DLS, and Zeta potential for their physical, morphological and structural properties. Nanoscale properties of materials under the influence of temperature were characterized through nanoindentation techniques. From quasi-static nanoindentation, it was observed that hardness and reduced modulus of the nanocomposites were increased significantly in direct proportion to the gold nanoparticle concentration. Gold nanoparticle concentration also showed positive impact on storagemodulus and thermal stability of the material. The obtained films were confirmed to be biocompatible by their ability to support growth of human cells in vitro. In summary, the results show enhanced mechanical properties with increasing gold nanoparticle concentration, and provide better understanding of the structure–property relationships of such biocompatiblematerials for potential biomedical applications. PMID:25280713

Upward shift of the vortex solid phase in high-temperature-superconducting wires through high density nanoparticle addition

DOE PAGES

Miura, Masashi; Maiorov, Boris; Balakirev, Fedor F.; ...

2016-02-08

Here, we show a simple and effective way to improve the vortex irreversibility line up to very high magnetic fields (60T) by increasing the density of second phase BaZrO 3 nanoparticles. (Y 0.77,Gd 0.23)Ba 2Cu 3O y films were grown on metal substrates with different concentration of BaZrO 3 nanoparticles by the metal organic deposition method. We find that upon increase of the BaZrO 3 concentration, the nanoparticle size remains constant but the twin-boundary density increases. Up to the highest nanoparticle concentration (n ~ 1.3 × 10 22/m 3), the irreversibility field (H irr) continues to increase with no signmore » of saturation up to 60 T, although the vortices vastly outnumber pinning centers. We find extremely high H irr, namely H irr = 30 T (H||45°) and 24 T (H||c) at 65 K and 58 T (H||45°) and 45 T (H||c) at 50K. The difference in pinning landscape shifts the vortex solid-liquid transition upwards, increasing the vortex region useful for power applications, while keeping the upper critical field, critical temperature and electronic mass anisotropy unchanged.« less

Cavity Control and Cooling of Nanoparticles in High Vacuum

NASA Astrophysics Data System (ADS)

Millen, James

2016-05-01

Levitated systems are a fascinating addition to the world of optically-controlled mechanical resonators. It is predicted that nanoparticles can be cooled to their c.o.m. ground state via the interaction with an optical cavity. By freeing the oscillator from clamping forces dissipation and decoherence is greatly reduced, leading to the potential to produce long-lived, macroscopically spread, mechanical quantum states, allowing tests of collapse models and any mass limit of quantum physics. Reaching the low pressures required to cavity-cool to the ground state has proved challenging. Our approach is to cavity cool a beam of nanoparticles in high vacuum. We can cool the c.o.m. motion of nanospheres, and control the rotation of nanorods, with the potential to produce cold, aligned nanostructures. Looking forward, we will utilize novel microcavities to enhance optomechanical cooling, preparing particles in a coherent beam ideally suited to ultra-high mass interferometry at 107 a.m.u.

A study of degradation resistance and cytocompatibility of super-hydrophobic coating on magnesium.

PubMed

Zhang, Yufen; Feyerabend, Frank; Tang, Shawei; Hu, Jin; Lu, Xiaopeng; Blawert, Carsten; Lin, Tiegui

2017-09-01

Calcium stearate based super-hydrophobic coating was deposited on plasma electrolytic oxidation (PEO) pre-treated magnesium substrate. The pre-treated magnesium and super-hydrophobic coating covered sample were characterized by scanning electron microscopy, X-ray diffraction and electrochemical corrosion measurements. The cytocompatibility and degradation resistance of magnesium, pre-treated magnesium and super-hydrophobic coating were analysed in terms of cell adhesion and osteoblast differentiation. The results indicate that the calcium stearate top coating shows super-hydrophobicity and that the surface is composed of micro/nanostructure. The super-hydrophobic coating covered sample shows higher barrier properties compared with the PEO pre-treated magnesium and bare magnesium. Human osteoblast proliferation, but not differentiation is enhanced by the PEO coating. Contrary, the super-hydrophobic coating reduces proliferation, but enhances differentiation of osteoblast, observable by the formation of hydroxyapatite. The combination of corrosion protection and cell reaction indicates that this system could be interesting for biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Hemocompatibility and cytocompatibility of pristine and plasma-treated silver-zeolite-chitosan composites

NASA Astrophysics Data System (ADS)

Taaca, Kathrina Lois M.; Vasquez, Magdaleno R.

2018-02-01

Silver-exchanged zeolite-chitosan (AgZ-Ch) composites with varying AgZ content were prepared by solvent casting and modified under argon (Ar) plasma excited by a 13.56 MHz radio frequency (RF) power source. Silver (Ag) was successfully incorporated in a natural zeolite host without losing its antibacterial activity against Escherichia coli and Staphylococcus aureus. The AgZ particles were incorporated into a chitosan matrix without making significant changes in the matrix structure. The composites also exhibited antibacterial sensitivity due to the inclusion of AgZ. Plasma treatment enhanced the surface wettability of polar and nonpolar test liquids of the composites. The average increase in total surface free energy after treatment was around 49% with the polar component having a significant change. Cytocompatibility tests showed at least 87% cell viability for pristine and plasma-treated composites comparable with supplemented RPMI as positive control. Hemocompatibility tests revealed that pristine composites does not promote hemolysis and the blood clotting ability is less than 10 min. Coupled with antibacterial property, the fabricated composites have promising biomedical applications.

In Situ Forming, Cytocompatible, and Self-Recoverable Tough Hydrogels Based on Dual Ionic and Click Cross-Linked Alginate.

PubMed

Ghanian, Mohammad Hossein; Mirzadeh, Hamid; Baharvand, Hossein

2018-05-14

A dual cross-linking strategy was developed to answer the urgent need for fatigue-resistant, cytocompatible, and in situ forming tough hydrogels. Clickable, yet calcium-binding derivatives of alginate were synthesized by partial substitution of its carboxyl functionalities with furan, which could come into Diels-Alder click reaction with maleimide end groups of a four arm poly(ethylene glycol) cross-linker. Tuning the cooperative viscoelastic action of transient ionic and permanent click cross-links within the single network of alginate provided a soft tough hydrogel with a set of interesting features: (i) immediate self-recovery under cyclic loading, (ii) highly efficient and autonomous self-healing upon fracture, (iii) in situ forming ability for molding and minimally invasive injection, (iv) capability for viable cell encapsulation, and (v) reactivity for on-demand biomolecule conjugation. The facile strategy is applicable to a wide range of natural and synthetic polymers by introducing the calcium binding and click reacting functional groups and can broaden the use of tough hydrogels in load-bearing, cell-laden applications such as soft tissue engineering and bioactuators.

Flexible photonic crystal membranes with nanoparticle high refractive index layers.

PubMed

Karrock, Torben; Paulsen, Moritz; Gerken, Martina

2017-01-01

Flexible photonic crystal slabs with an area of 2 cm 2 are fabricated by nanoimprint replication of a 400 nm period linear grating nanostructure into a ≈60 µm thick polydimethylsiloxane membrane and subsequent spin coating of a high refractive index titanium dioxide nanoparticle layer. Samples are prepared with different nanoparticle concentrations. Guided-mode resonances with a quality factor of Q ≈ 40 are observed. The highly flexible nature of the membranes allows for stretching of up to 20% elongation. Resonance peak positions for unstretched samples vary from 555 to 630 nm depending on the particle concentration. Stretching results in a resonance shift for these peaks of up to ≈80 nm, i.e., 3.9 nm per % strain. The color impression of the samples observed with crossed-polarization filters changes from the green to the red regime. The high tunability renders these membranes promising for both tunable optical devices as well as visualization devices.

Perovskite nanoparticle-sensitized Ga 2O 3 nanorod arrays for CO detection at high temperature

DOE PAGES

Lin, Hui -Jan; Baltrus, John P.; Gao, Haiyong; ...

2016-04-04

Here, noble metal nanoparticles are extensively used for sensitizing metal oxide chemical sensors through the catalytic spillover mechanism. However, due to earth-scarcity and high cost of noble metals, finding replacements presents a great economic benefit. Besides, high temperature and harsh environment sensor applications demand material stability under conditions approaching thermal and chemical stability limits of noble metals. In this study, we employed thermally stable perovskite-type La 0.8Sr 0.2FeO 3 (LSFO) nanoparticle surface decoration on Ga 2O 3 nanorod array gas sensors and discovered an order of magnitude enhanced sensitivity to carbon monoxide at 500 °C. The LSFO nanoparticle catalysts wasmore » of comparable performance to that achieved by Pt nanoparticles, with a much lower weight loading than Pt. Detailed electron microscopy and X-ray photoelectron spectroscopy studies suggested the LSFO nanoparticle sensitization effect is attributed to a spillover-like effect associated with the gas-LSFO-Ga 2O 3 triple-interfaces that spread the negatively charged surface oxygen ions from LSFO nanoparticles surfaces over to β-Ga 2O 3 nanorod surfaces with faster surface CO oxidation reactions.« less

Perovskite Nanoparticle-Sensitized Ga2O3 Nanorod Arrays for CO Detection at High Temperature.

PubMed

Lin, Hui-Jan; Baltrus, John P; Gao, Haiyong; Ding, Yong; Nam, Chang-Yong; Ohodnicki, Paul; Gao, Pu-Xian

2016-04-13

Noble metal nanoparticles are extensively used for sensitizing metal oxide chemical sensors through the catalytic spillover mechanism. However, due to earth-scarcity and high cost of noble metals, finding replacements presents a great economic benefit. Besides, high temperature and harsh environment sensor applications demand material stability under conditions approaching thermal and chemical stability limits of noble metals. In this study, we employed thermally stable perovskite-type La(0.8)Sr(0.2)FeO3 (LSFO) nanoparticle surface decoration on Ga2O3 nanorod array gas sensors and discovered an order of magnitude enhanced sensitivity to carbon monoxide at 500 °C. The LSFO nanoparticle catalysts was of comparable performance to that achieved by Pt nanoparticles, with a much lower weight loading than Pt. Detailed electron microscopy and X-ray photoelectron spectroscopy studies suggested the LSFO nanoparticle sensitization effect is attributed to a spillover-like effect associated with the gas-LSFO-Ga2O3 triple-interfaces that spread the negatively charged surface oxygen ions from LSFO nanoparticles surfaces over to β-Ga2O3 nanorod surfaces with faster surface CO oxidation reactions.

Synthesis of thiolated chitosan and preparation nanoparticles with sodium alginate for ocular drug delivery.

PubMed

Zhu, Xuan; Su, Meiqin; Tang, Shaoheng; Wang, Lingsong; Liang, Xinfang; Meng, Feihong; Hong, Ying; Xu, Zhiran

2012-01-01

The goal of the present study was to synthesize mucoadhesive polymer - thiolated chitosan (TCS) from chitosan (CS), then prepared CS/TCS-sodium alginate nanoparticles (CS/TCS-SA NPs), determined which was more potential for ocular drug delivery. A new method for preparing TCS was developed, and the characteristics were determined using Fourier transform infrared spectroscopy and the degree of thiol immobilized was measured by Ellman's reagent. Human corneal epithelium (HCE) cells were incubated with different concentrations of TCS for 48 h to determine the cell viabilities. CS/TCS-SA NPs were prepared and optimized by a modified ionic gelation method. The particle sizes, zeta potentials, Scanning electron microscopy images, mucoadhesion, in vitro cell uptake and in vivo studies of the two types of NP were compared. The new method enabled a high degree of thiol substitution of TCS, up to 1,411.01±4.02 μmol/g. In vitro cytocompatibility results suggest that TCS is nontoxic. Compared to CS-SA NPs, TCS-SA NPs were more stable, with higher mucoadhesive properties and could deliver greater amounts of drugs into HCE cells in vitro and cornea in vivo. TCS-SA NPs have better delivery capability, suggesting they have good potential for ocular drug delivery applications.

High sensitivity DNA detection using gold nanoparticle functionalised polyaniline nanofibres.

PubMed

Spain, Elaine; Kojima, Robert; Kaner, Richard B; Wallace, Gordan G; O'Grady, Justin; Lacey, Katrina; Barry, Thomas; Keyes, Tia E; Forster, Robert J

2011-01-15

Polyaniline (PANI) nanofibres (PANI-NF) have been modified with chemically grown gold nanoparticles to give a nanocomposite material (PANI-NF-AuNP) and deposited on gold electrodes. Single stranded capture DNA was then bound to the gold nanoparticles and the underlying gold electrode and allowed to hybridise with a complementary target strand that is uniquely associated with the pathogen, Staphylococcus aureus (S. aureus), that causes mastitis. Significantly, cyclic voltammetry demonstrates that deposition of the gold nanoparticles increases the area available for DNA immobilisation by a factor of approximately 4. EPR reveals that the addition of the Au nanoparticles efficiently decreases the interactions between adjacent PANI chains and/or motional broadening. Finally, a second horseradish peroxidase (HRP) labelled DNA strand hybridises with the target allowing the concentration of the target DNA to be detected by monitoring the reduction of a hydroquinone mediator in solution. The sensors have a wide dynamic range, excellent ability to discriminate DNA mismatches and a high sensitivity. Semi-log plots of the pathogen DNA concentration vs. faradaic current were linear from 150×10(-12) to 1×10(-6) mol L(-1) and pM concentrations could be detected without the need for molecular, e.g., PCR or NASBA, amplification. Copyright © 2010 Elsevier B.V. All rights reserved.

Fabrication and cytocompatibility of spherical magnesium ammonium phosphate granules.

PubMed

Christel, Theresa; Geffers, Martha; Klammert, Uwe; Nies, Berthold; Höß, Andreas; Groll, Jürgen; Kübler, Alexander C; Gbureck, Uwe

2014-09-01

Magnesium phosphate compounds, as for example struvite (MgNH4PO4·6H2O), have comparable characteristics to calcium phosphate bone substitutes, but degrade faster under physiological conditions. In the present work, we used a struvite forming calcium doped magnesium phosphate cement with the formulation Ca0.75Mg2.25(PO4)2 and an ammonium phosphate containing aqueous solution to produce round-shaped granules. For the fabrication of spherical granules, the cement paste was dispersed in a lipophilic liquid and stabilized by surfactants. The granules were characterized with respect to morphology, size distribution, phase composition, compressive strength, biocompatibility and solubility. In general, it was seen that small granules can hardly be produced by means of emulsification, when the raw material is a hydraulic paste, because long setting times promote coalescence of initially small unhardened cement droplets. Here, this problem was solved by using an aqueous solution containing both the secondary (NH4)2HPO4 and primary ammonium phosphates NH4H2PO4 to accelerate the setting reaction. This resulted in granules with 97 wt.% having a size in the range between 200 and 1,000 μm. The novel solution composition doubled the compressive strength of the cement to 37 ± 5 MPa without affecting either the conversion to struvite or the cytocompatibility using human fetal osteoblasts. Copyright © 2014 Elsevier B.V. All rights reserved.

Gadolinium-based nanoparticles for highly efficient T1-weighted magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Lim, Eun-Kyung; Kang, Byunghoon; Choi, Yuna; Jang, Eunji; Han, Seungmin; Lee, Kwangyeol; Suh, Jin-Suck; Haam, Seungjoo; Huh, Yong-Min

2014-06-01

We developed Pyrene-Gadolinium (Py-Gd) nanoparticles as pH-sensitive magnetic resonance imaging (MRI) contrast agents capable of showing a high-Mr signal in cancer-specific environments, such as acidic conditions. Py-Gd nanoparticles were prepared by coating Py-Gd, which is a complex of gadolinium with pyrenyl molecules, with pyrenyl polyethyleneglycol PEG using a nano-emulsion method. These particles show better longitudinal relaxation time (T1) MR signals in acidic conditions than they do in neutral conditions. Furthermore, the particles exhibit biocompatibility and MR contrast effects in both in vitro and in vivo studies. From these results, we confirm that Py-Gd nanoparticles have the potential to be applied for accurate cancer diagnosis and therapy.

Optimization of β-carotene loaded solid lipid nanoparticles preparation using a high shear homogenization technique

NASA Astrophysics Data System (ADS)

Triplett, Michael D.; Rathman, James F.

2009-04-01

Using statistical experimental design methodologies, the solid lipid nanoparticle design space was found to be more robust than previously shown in literature. Formulation and high shear homogenization process effects on solid lipid nanoparticle size distribution, stability, drug loading, and drug release have been investigated. Experimentation indicated stearic acid as the optimal lipid, sodium taurocholate as the optimal cosurfactant, an optimum lecithin to sodium taurocholate ratio of 3:1, and an inverse relationship between mixing time and speed and nanoparticle size and polydispersity. Having defined the base solid lipid nanoparticle system, β-carotene was incorporated into stearic acid nanoparticles to investigate the effects of introducing a drug into the base solid lipid nanoparticle system. The presence of β-carotene produced a significant effect on the optimal formulation and process conditions, but the design space was found to be robust enough to accommodate the drug. β-Carotene entrapment efficiency averaged 40%. β-Carotene was retained in the nanoparticles for 1 month. As demonstrated herein, solid lipid nanoparticle technology can be sufficiently robust from a design standpoint to become commercially viable.

Targeted delivery of 5-fluorouracil to HT-29 cells using high efficient folic acid-conjugated nanoparticles.

PubMed

Wang, Yichao; Li, Puwang; Chen, Lijue; Gao, Weimin; Zeng, Fanbo; Kong, Ling Xue

2015-02-01

The incorporation of a high percentage of targeting molecules into drug delivery system is one of the important methods for improving efficacy of targeting therapeutic drugs to cancer cells. PLGA-based drug delivery carriers with folic acid (FA) as targeting molecule have a low targeting efficiency due to a low FA conjugation ratio. In this work, we fabricated a FA-conjugated PLGA system using a crosslinker 1, 3-diaminopropane and have achieved a high conjugation ratio of 46.7% (mol/mol). The as-prepared PLGA-based biomaterial was used to encapsulate therapeutic drug 5-fluorouracil (5-FU) into nanoparticles. In the in vitro experiments, an IC₅₀ of 5.69 µg/mL has been achieved for 5-FU loaded PLGA-1, 3-diaminopropane-folic acid nanoparticles on HT-29 cancer cells and is significantly lower than that of 5-FU and 5-FU loaded PLGA nanoparticles which only have an IC₅₀ of 22.9 and 14.17 µg/mL, respectively. The fluorescent microscopy images showed that nanoparticles with FA are largely taken up by HT-29 cancer cells and the targeting nanoparticles have more affinity to cancer cells than the pure drugs and untreated nanoparticles. Therefore, the 1, 3-diaminopropane can facilitate the conjugation of FA to PLGA to form a novel polymer and 5-FU loaded PLGA-1, 3-diaminopropane-folic acid nanoparticles can be a highly efficient system for specific delivery of drugs to cancer cells.

Highly magnetic Co nanoparticles fabricated by X-ray radiolysis

NASA Astrophysics Data System (ADS)

Clifford, Dustin M.; Castano, Carlos E.; Rojas, Jessika V.

2018-03-01

Advanced routes for the synthesis of nanomaterials, such as ferromagnetic nanoparticles, are being explored that are easy to perform using cost-effective and non-toxic precursors. Radiolytic syntheses based on the use of X-rays as ionizing radiation are promising towards this effort. X-rays were used to produce highly magnetic cobalt nanoparticles (NPs), stable in air up to 200 °C, from the radiolysis of water. Crystal structure analysis by XRD indicates a mixture of Cofcc, 63%, and Cohcp, 37%, phases. Magnetic analysis by VSM gave a saturation magnetization (Ms) 136 emu/g at 1 T and coercivity (Hc) = 325 Oe when the reaction solution was purged with N2 while an air-purged treatment resulted in Co NPs having 102 emu/g with a coercivity (Hc) 270 Oe. Overall, the reduction of Co2+ occurred in an aqueous reaction environment without addition of chemical reductants resulting in Co NPs with size distribution from 20 to 140 nm. This clean approach at ambient temperature produced highly magnetic Co NPs that may be used for switching devices (i.e. reed switches) or as additives for alloys that require high Curie points.

Highly efficient antibody immobilization with multimeric protein Gs coupled magnetic silica nanoparticles

NASA Astrophysics Data System (ADS)

Lee, J. H.; Choi, H. K.; Chang, J. H.

2011-10-01

This work reports the immobilization of monomeric, dimeric and trimer protein Gs onto silica magnetic nanoparticles for self-oriented antibody immobilization. To achieve this, we initially prepared the silica-coated magnetic nanoparticle having about 170 nm diameters. The surface of the silica coated magnetic nanoparticles was modified with 3- aminopropyl-trimethoxysilane (APTMS) to chemically link to multimeric protein Gs. The conjugation of amino groups on the SiO2-MNPs to cysteine tagged in multimeric protein Gs was performed using a sulfo-SMCC coupling procedure. The binding efficiencies of monomer, dimer and trimer were 77 %, 67 % and 55 % respectively. However, the efficiencies of antibody immobilization were 70 %, 83 % and 95 % for monomeric, dimeric and trimeric protein G, respectively. To prove the enhancement of accessibility by using multimeric protein G, FITC labeled goat-anti-mouse IgG was treated to mouse IgG immobilized magnetic silica nanoparticles through multimeric protein G. FITC labeled goat anti-mouse IgGs were more easily bound to mouse IgG immobilized by trimeric protein G than others. Finally protein G bound silica magnetic nanoparticles were utilized to develop highly sensitive immunoassay to detect hepatitis B antigen.

High performance magneto-fluorescent nanoparticles assembled from terbium and gadolinium 1,3-diketones

PubMed Central

Zairov, Rustem; Mustafina, Asiya; Shamsutdinova, Nataliya; Nizameev, Irek; Moreira, Beatriz; Sudakova, Svetlana; Podyachev, Sergey; Fattakhova, Alfia; Safina, Gulnara; Lundstrom, Ingemar; Gubaidullin, Aidar; Vomiero, Alberto

2017-01-01

Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[4]arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted. The core composition was optimized for the longitudinal relaxivity to be greater than that of the commercial magnetic resonance imaging (MRI) contrast agents together with high level of Tb(III)-centered luminescence. The tuning of both magnetic and luminescent output of nanoparticles is obtained via the simple variation of lanthanide chelates concentrations in the initial synthetic solution. The exposure of the pheochromocytoma 12 (PC 12) tumor cells and periphery human blood lymphocytes to nanoparticles results in negligible effect on cell viability, decreased platelet aggregation and bright coloring, indicating the nanoparticles as promising candidates for dual magneto-fluorescent bioimaging. PMID:28091590

High performance magneto-fluorescent nanoparticles assembled from terbium and gadolinium 1,3-diketones

NASA Astrophysics Data System (ADS)

Zairov, Rustem; Mustafina, Asiya; Shamsutdinova, Nataliya; Nizameev, Irek; Moreira, Beatriz; Sudakova, Svetlana; Podyachev, Sergey; Fattakhova, Alfia; Safina, Gulnara; Lundstrom, Ingemar; Gubaidullin, Aidar; Vomiero, Alberto

2017-01-01

Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[4]arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted. The core composition was optimized for the longitudinal relaxivity to be greater than that of the commercial magnetic resonance imaging (MRI) contrast agents together with high level of Tb(III)-centered luminescence. The tuning of both magnetic and luminescent output of nanoparticles is obtained via the simple variation of lanthanide chelates concentrations in the initial synthetic solution. The exposure of the pheochromocytoma 12 (PC 12) tumor cells and periphery human blood lymphocytes to nanoparticles results in negligible effect on cell viability, decreased platelet aggregation and bright coloring, indicating the nanoparticles as promising candidates for dual magneto-fluorescent bioimaging.

The sensitive and selective adsorption of aromatic compounds with highly crosslinked polymer nanoparticles

NASA Astrophysics Data System (ADS)

Liu, Shuqin; Chen, Darui; Zheng, Juan; Zeng, Lewei; Jiang, Jijun; Jiang, Ruifeng; Zhu, Fang; Shen, Yong; Wu, Dingcai; Ouyang, Gangfeng

2015-10-01

This study presents the preparation and characterization of a nanoscale Davankov-type hyper-crosslinked-polymer (HCP) as an adsorbent of benzene-ring-containing dyes and organic pollutants. HCP nanoparticles post-crosslinked from a poly(DVB-co-VBC) precursor were synthesized in this study, possessing ultrahigh surface area, hydrophobicity and stability. The as-synthesized Davankov-type HCP exhibited a rapid and selective adsorption ability towards the benzene-ring-containing dyes due to its highly conjugated structure. Besides, for the first time, the prepared HCP nanoparticles were adopted for the adsorption of nonpolar organic pollutants by means of solid-phase microextraction (SPME). Owing to its high hydrophobicity, diverse pore size distribution and highly conjugated structure, a 10 μm HCP coating exhibited excellent adsorption abilities towards benzene-ring-containing polycyclic aromatic hydrocarbons (PAHs) and benzene series compounds (benzene, toluene, ethylbenzene and o-xylene; abbreviated to BTEX) and to highly hydrophobic long-chain n-alkanes. Finally, the HCP-nanoparticles-coated SPME fiber was applied to the simultaneous analysis of five PAHs in environmental water samples and satisfactory recoveries were achieved. The findings could provide a new benchmark for the exploitation of superb HCPs as effective adsorbents for SPME or other adsorption applications.This study presents the preparation and characterization of a nanoscale Davankov-type hyper-crosslinked-polymer (HCP) as an adsorbent of benzene-ring-containing dyes and organic pollutants. HCP nanoparticles post-crosslinked from a poly(DVB-co-VBC) precursor were synthesized in this study, possessing ultrahigh surface area, hydrophobicity and stability. The as-synthesized Davankov-type HCP exhibited a rapid and selective adsorption ability towards the benzene-ring-containing dyes due to its highly conjugated structure. Besides, for the first time, the prepared HCP nanoparticles were adopted for the

Magnetically stimulated ciprofloxacin release from polymeric microspheres entrapping iron oxide nanoparticles

PubMed Central

Sirivisoot, Sirinrath; Harrison, Benjamin S

2015-01-01

To extend the external control capability of drug release, iron oxide nanoparticles (NPs) encapsulated into polymeric microspheres were used as magnetic media to stimulate drug release using an alternating magnetic field. Chemically synthesized iron oxide NPs, maghemite or hematite, and the antibiotic ciprofloxacin were encapsulated together within polycaprolactone microspheres. The polycaprolactone microspheres entrapping ciprofloxacin and magnetic NPs could be triggered for immediate drug release by magnetic stimulation at a maximum value of 40%. Moreover, the microspheres were cytocompatible with fibroblasts in vitro with a cell viability percentage of more than 100% relative to a nontreated control after 24 hours of culture. Macrophage cell cultures showed no signs of increased inflammatory responses after in vitro incubation for 56 hours. Treatment of Staphylococcus aureus with the magnetic microspheres under an alternating (isolating) magnetic field increased bacterial inhibition further after 2 days and 5 days in a broth inhibition assay. The findings of the present study indicate that iron oxide NPs, maghemite and hematite, can be used as media for stimulation by an external magnetic energy to activate immediate drug release. PMID:26185446

Fast adsorption kinetics of highly dispersed ultrafine nickel/carbon nanoparticles for organic dye removal

NASA Astrophysics Data System (ADS)

Kim, Taek-Seung; Song, Hee Jo; Dar, Mushtaq Ahmad; Lee, Hack-Jun; Kim, Dong-Wan

2018-05-01

Magnetic metal/carbon nano-materials are attractive for pollutant adsorption and removal. In this study, ultrafine nickel/carbon nanoparticles are successfully prepared via electrical wire explosion processing in ethanol media for the elimination of pollutant organic dyes such as Rhodamine B and methylene blue in aqueous solutions. High specific surface areas originating from both the nano-sized particles and the existence of carbon on the surface of Ni nanoparticles enhance dye adsorption capacity. In addition to this, the excellent dispersity of Ni/C nanoparticles in aqueous dye solutions leads to superior adsorption rates. The adsorption kinetics for the removal of organic dyes by Ni/C nanoparticles agree with a pseudo-second-order model and follow Freundlich adsorption isotherm behavior.

Chemically attached gold nanoparticle-carbon nanotube hybrids for highly sensitive SERS substrate

NASA Astrophysics Data System (ADS)

Beqa, Lule; Singh, Anant Kumar; Fan, Zheng; Senapati, Dulal; Ray, Paresh Chandra

2011-08-01

Surface-enhanced Raman spectroscopy (SERS) has been shown as one of the most powerful analytical tool with high sensitivity. In this manuscript, we report the chemical design of SERS substrate, based on gold nanoparticles of different shapes-decorated with carbon nanotube with an enhancement factor of 7.5 × 1010. Shape dependent result shows that popcorn shape gold nanoparticle decorated SWCNT is the best choice for SERS substrate due to the existence of 'lightning rod effect' through several sharp edges or corners. Our results provide a good approach to develop highly sensitive SERS substrates and can help to improve the fundamental understanding of SERS phenomena.

Synthesis of highly stable silver nanoparticles through a novel green method using Mirabillis jalapa for antibacterial, nonlinear optical applications

NASA Astrophysics Data System (ADS)

Pugazhendhi, S.; Palanisamy, P. K.; Jayavel, R.

2018-05-01

Green synthesis techniques are developing as more simplistic and eco-friendly approach for the synthesis of metal nanoparticles compared to chemical reduction methods. Herein we report Synthesis of highly stable silver nanoparticles using Mirabillis jalapa seed extract as a reducing and capping agent. The as-prepared silver nanoparticles were characterized by UV-vis spectroscopy (UV-vis) to confirm the formation of silver nanoparticles by its characteristic surface plasmon resonance peak observed at 420 nm. The Powder X-ray diffraction (P-XRD) revealed the structure and crystalline nature of synthesized silver nanoparticles, The Fourier transform infra-red spectroscopic (FT-IR) revealed the presence of the biomolecules in the extract that acted as reducing as well stabilizing agent. The high resolution transmission electron microscopic (HRTEM) images divulged that the synthesized silver nanoparticles were spherical in shape and poly dispersed. The energy dispersive X-ray diffraction (EDX) profile revealed the elements present in the as-synthesized colloidal silver nanoparticles and its percentages. The Zeta potential measured for silver nanoparticles evidenced that the prepared silver nanoparticles owned high stability in room temperature itself. The as-synthesized silver nanoparticles (AgNPs) in colloidal form were showed good antimicrobial effects and it's were found to exhibit third order optical nonlinearity as studied by Z-scan technique using 532 nm Nd:YAG (SHG) CW laser beam (COHERENT-Compass 215 M-50 diode pumped) output as source. The negative nonlinearity observed was well utilized for the study of optical limiting behavior of the silver nanoparticles.

Immobilization of iron oxide nanoparticles within alginate nanogels for enhanced MR imaging applications.

PubMed

Sun, Wenjie; Yang, Jia; Zhu, Jianzhi; Zhou, Yiwei; Li, Jingchao; Zhu, Xiaoyue; Shen, Mingwu; Zhang, Guixiang; Shi, Xiangyang

2016-10-20

We report the design of iron oxide (Fe3O4) nanoparticle (NP)-immobilized alginate (AG) nanogels (NGs) as a novel contrast agent for enhanced magnetic resonance (MR) imaging applications. In this study, an aqueous solution of AG activated by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride was double emulsified to form NGs, followed by in situ cross-linking with polyethyleneimine (PEI)-coated Fe3O4 NPs (PEI-Fe3O4 NPs). The resultant Fe3O4 NP-immobilized AG NGs (AG/PEI-Fe3O4 NGs) were characterized via different techniques. Our results reveal that the hybrid NGs with a size of 186.1 ± 33.1 nm are water dispersible, colloidally stable, and cytocompatible in the given concentration range. Importantly, these NGs have a high r2 relaxivity (170.87 mM(-1) s(-1)) due to the high loading of Fe3O4 NPs within the NGs, and can be more significantly uptaken by cancer cells when compared with carboxylated Fe3O4 NPs. The formed AG/PEI-Fe3O4 NGs are able to be used as an effective contrast agent for the MR imaging of cancer cells in vitro and the xenografted tumor model in vivo after intravenous injection. The developed AG/PEI-Fe3O4 NGs may hold great promise for use as a novel contrast agent for the enhanced MR imaging of different biological systems.

Achieving high-efficiency emission depletion nanoscopy by employing cross relaxation in upconversion nanoparticles.

PubMed

Zhan, Qiuqiang; Liu, Haichun; Wang, Baoju; Wu, Qiusheng; Pu, Rui; Zhou, Chao; Huang, Bingru; Peng, Xingyun; Ågren, Hans; He, Sailing

2017-10-20

Stimulated emission depletion microscopy provides a powerful sub-diffraction imaging modality for life science studies. Conventionally, stimulated emission depletion requires a relatively high light intensity to obtain an adequate depletion efficiency through only light-matter interaction. Here we show efficient emission depletion for a class of lanthanide-doped upconversion nanoparticles with the assistance of interionic cross relaxation, which significantly lowers the laser intensity requirements of optical depletion. We demonstrate two-color super-resolution imaging using upconversion nanoparticles (resolution ~ 66 nm) with a single pair of excitation/depletion beams. In addition, we show super-resolution imaging of immunostained cytoskeleton structures of fixed cells (resolution ~ 82 nm) using upconversion nanoparticles. These achievements provide a new perspective for the development of photoswitchable luminescent probes and will broaden the applications of lanthanide-doped nanoparticles for sub-diffraction microscopic imaging.

A highly sensitive magnetic biosensor for detection and quantification of anticancer drugs tagged to superparamagnetic nanoparticles

NASA Astrophysics Data System (ADS)

Devkota, J.; Wingo, J.; Mai, T. T. T.; Nguyen, X. P.; Huong, N. T.; Mukherjee, P.; Srikanth, H.; Phan, M. H.

2014-05-01

We report on a highly sensitive magnetic biosensor based on the magneto-reactance (MX) effect of a Co65Fe4Ni2Si15B14 amorphous ribbon with a nanohole-patterned surface for detection and quantification of anticancer drugs (Curcumin) tagged to superparamagnetic (Fe3O4) nanoparticles. Fe3O4 nanoparticles (mean size, ˜10 nm) were first coated with Alginate, and Curcumin was then tagged to the nanoparticles. The detection and quantification of Curcumin were assessed by the change in MX of the ribbon subject to varying concentrations of the Fe3O4 nanoparticles to which Curcumin was tagged. A high capacity of the MX-based biosensor in quantitative analysis of Curcumin-loaded Fe3O4 nanoparticles was achieved in the range of 0-50 ng/ml, beyond which the detection sensitivity of the sensor remained unchanged. The detection sensitivity of the biosensor reached an extremely high value of 30%, which is about 4-5 times higher than that of a magneto-impedance (MI) based biosensor. This biosensor is well suited for detection of low-concentration magnetic biomarkers in biological systems.

Highly sensitive wearable strain sensor based on silver nanowires and nanoparticles.

PubMed

Shengbo, Sang; Lihua, Liu; Aoqun, Jian; Qianqian, Duan; Jianlong, Ji; Qiang, Zhang; Wendong, Zhang

2018-06-22

Here, we propose a highly sensitive and stretchable strain sensor based on silver nanoparticles and nanowires (Ag NPs and NWs), advancing the rapid development of electronic skin. To improve the sensitivity of strain sensors based on silver nanowires (Ag NWs), Ag NPs and NWs were added to polydimethylsiloxane (PDMS) as an aid filler. Silver nanoparticles (Ag NPs) increase the conductive paths for electrons, leading to the low resistance of the resulting sensor (14.9 Ω). The strain sensor based on Ag NPs and NWs showed strong piezoresistivity with a tunable gauge factor (GF) at 3766, and a change in resistance as the strain linearly increased from 0% to 28.1%. The high GF demonstrates the irreplaceable role of Ag NPs in the sensor. Moreover, the applicability of our high-performance strain sensor has been demonstrated by its ability to sense movements caused by human talking, finger bending, wrist raising and walking.

Highly sensitive wearable strain sensor based on silver nanowires and nanoparticles

NASA Astrophysics Data System (ADS)

Shengbo, Sang; Lihua, Liu; Aoqun, Jian; Qianqian, Duan; Jianlong, Ji; Qiang, Zhang; Wendong, Zhang

2018-06-01

Here, we propose a highly sensitive and stretchable strain sensor based on silver nanoparticles and nanowires (Ag NPs and NWs), advancing the rapid development of electronic skin. To improve the sensitivity of strain sensors based on silver nanowires (Ag NWs), Ag NPs and NWs were added to polydimethylsiloxane (PDMS) as an aid filler. Silver nanoparticles (Ag NPs) increase the conductive paths for electrons, leading to the low resistance of the resulting sensor (14.9 Ω). The strain sensor based on Ag NPs and NWs showed strong piezoresistivity with a tunable gauge factor (GF) at 3766, and a change in resistance as the strain linearly increased from 0% to 28.1%. The high GF demonstrates the irreplaceable role of Ag NPs in the sensor. Moreover, the applicability of our high-performance strain sensor has been demonstrated by its ability to sense movements caused by human talking, finger bending, wrist raising and walking.

Synthesis of curcumin-loaded chitosan phosphate nanoparticle and study of its cytotoxicity and antimicrobial activity.

PubMed

Deka, C; Aidew, L; Devi, N; Buragohain, A K; Kakati, D K

2016-11-01

Curcumin has acquired an important position in the treatment of various diseases. But its use, as a chemotherapeutic agent, is limited due to its low water solubility, poor bioavailability, and its sensitive nature at the physiological pH. To overcome this, curcumin was loaded into chitosan phosphate nanoparticles (CPNs). The loading efficiency was found to be 84%. DLS studies revealed the average particle size of CPNs and curcumin-loaded CPNs as 53 and 91 nm, respectively, and TEM results supplemented these values. A sustained release pattern was noticed and the amount of curcumin released in acidic pH was higher than at physiological pH. The curcumin nanoformulation exhibited proficient activity against both Gram-positive and Gram-negative bacteria as well as fungus. Cytocompatibility of the nanoformulations against peripheral blood mononuclear cells (PBMCs) and murine monocyte-macrophage cell line was confirmed by incubating with PBMCs and murine monocyte-macrophage cell line.

Imaging interactions of metal oxide nanoparticles with macrophage cells by ultra-high resolution scanning electron microscopy techniques.

PubMed

Plascencia-Villa, Germán; Starr, Clarise R; Armstrong, Linda S; Ponce, Arturo; José-Yacamán, Miguel

2012-11-01

Use of engineered metal oxide nanoparticles in a plethora of biological applications and custom products has warned about some possible dose-dependent cytotoxic effects. Macrophages are key components of the innate immune system used to study possible toxic effects and internalization of different nanoparticulate materials. In this work, ultra-high resolution field emission scanning electron microscopy (FE-SEM) was used to offer new insights into the dynamical processes of interaction of nanomaterials with macrophage cells dosed with different concentrations of metal oxide nanoparticles (CeO(2), TiO(2) and ZnO). The versatility of FE-SEM has allowed obtaining a detailed characterization of processes of adsorption and endocytosis of nanoparticles, by using advanced analytical and imaging techniques on complete unstained uncoated cells, including secondary electron imaging, high-sensitive backscattered electron imaging, X-ray microanalysis and stereoimaging. Low voltage BF/DF-STEM confirmed nanoparticle adsorption and internalization into endosomes of CeO(2) and TiO(2), whereas ZnO develop apoptosis after 24 h of interaction caused by dissolution and invasion of cell nucleus. Ultra-high resolution scanning electron microscopy techniques provided new insights into interactions of inorganic nanoparticles with macrophage cells with high spatial resolution.

Imaging interactions of metal oxide nanoparticles with macrophage cells by ultra-high resolution scanning electron microscopy techniques†

PubMed Central

Plascencia-Villa, Germán; Starr, Clarise R.; Armstrong, Linda S.; Ponce, Arturo

2016-01-01

Use of engineered metal oxide nanoparticles in a plethora of biological applications and custom products has warned about some possible dose-dependent cytotoxic effects. Macrophages are key components of the innate immune system used to study possible toxic effects and internalization of different nanoparticulate materials. In this work, ultra-high resolution field emission scanning electron microscopy (FE-SEM) was used to offer new insights into the dynamical processes of interaction of nanomaterials with macrophage cells dosed with different concentrations of metal oxide nanoparticles (CeO2, TiO2 and ZnO). The versatility of FE-SEM has allowed obtaining a detailed characterization of processes of adsorption and endocytosis of nanoparticles, by using advanced analytical and imaging techniques on complete unstained uncoated cells, including secondary electron imaging, high-sensitive backscattered electron imaging, X-ray microanalysis and stereoimaging. Low voltage BF/DF-STEM confirmed nanoparticle adsorption and internalization into endosomes of CeO2 and TiO2, whereas ZnO develop apoptosis after 24 h of interaction caused by dissolution and invasion of cell nucleus. Ultra-high resolution scanning electron microscopy techniques provided new insights into interactions of inorganic nanoparticles with macrophage cells with high spatial resolution. PMID:23023106

Tunable synthesis and acetylation of dendrimer-entrapped or dendrimer-stabilized gold-silver alloy nanoparticles.

PubMed

Liu, Hui; Shen, Mingwu; Zhao, Jinglong; Guo, Rui; Cao, Xueyan; Zhang, Guixiang; Shi, Xiangyang

2012-06-01

In this study, amine-terminated generation 5 poly(amidoamine) dendrimers were used as templates or stabilizers to synthesize dendrimer-entrapped or dendrimer-stabilized Au-Ag alloy nanoparticles (NPs) with different gold atom/silver atom/dendrimer molar ratios with the assistance of sodium borohydride reduction chemistry. Following a one-step acetylation reaction to transform the dendrimer terminal amines to acetyl groups, a series of dendrimer-entrapped or dendrimer-stabilized Au-Ag alloy NPs with terminal acetyl groups were formed. The formed Au-Ag alloy NPs before and after acetylation reaction were characterized using different techniques. We showed that the optical property and the size of the bimetallic NPs were greatly affected by the metal composition. At the constant total metal atom/dendrimer molar ratio, the size of the alloy NPs decreased with the gold content. The formed Au-Ag alloy NPs were stable at different pH (pH 5-8) and temperature (4-50°C) conditions. X-ray absorption coefficient measurements showed that the attenuation of the binary NPs was dependent on both the gold content and the surface modification. With the increase of gold content in the binary NPs, their X-ray attenuation intensity was significantly enhanced. At a given metal composition, the X-ray attenuation intensity of the binary NPs was enhanced after acetylation. Cytotoxicity assays showed that after acetylation, the cytocompatibility of Au-Ag alloy NPs was significantly improved. With the controllable particle size and optical property, metal composition-dependent X-ray attenuation characteristics, and improved cytocompatibility after acetylation, these dendrimer-entrapped or dendrimer-stabilized Au-Ag alloy NPs should have a promising potential for CT imaging and other biomedical applications. Copyright © 2012 Elsevier B.V. All rights reserved.

Examining nanoparticle assemblies using high spatial resolution x-ray microtomography

NASA Astrophysics Data System (ADS)

Jenneson, P. M.; Luggar, R. D.; Morton, E. J.; Gundogdu, O.; Tüzün, U.

2004-09-01

An experimental system has been designed to examine the assembly of nanoparticles in a variety of process engineering applications. These applications include the harvesting from solutions of nanoparticles into green parts, and the subsequent sintering into finished components. The system is based on an x-ray microtomography with a spatial resolution down to 5μm. The theoretical limitations in x-ray imaging are considered to allow experimental optimization. A standard nondestructive evaluation type apparatus with a small focal-spot x-ray tube, high-resolution complementary metal oxide semiconductor flat-panel pixellated detector, and a mechanical rotational stage is used to image the static systems. Dynamic sintering processes are imaged using the same x-ray source and detector but a custom rotational stage which is contained in an environmental chamber where the temperature, atmospheric pressure, and compaction force can be controlled. Three-dimensional tomographic data sets are presented here for samples from the pharmaceutical, nutraceutical, biotechnology, and nanoparticle handling industries and show the microscopic features and defects which can be resolved with the system.

In situ preparation of water-soluble ginsenoside Rh2-entrapped bovine serum albumin nanoparticles: in vitro cytocompatibility studies.

PubMed

Singh, Priyanka; Kim, Yeon Ju; Singh, Hina; Ahn, Sungeun; Castro-Aceituno, Verónica; Yang, Deok Chun

2017-01-01

The present study investigates a simple and convenient one-step procedure for the preparation of bovine serum albumin (BSA)-Rh2 nanoparticles (NPs) at room temperature. In this work, ginsenoside Rh2 was entrapped within the BSA protein to form BSA-Rh2 NPs to enhance the aqueous solubility, stability, and therapeutic efficacy of Rh2. The physiochemical characterization by high-performance liquid chromatography, nuclear magnetic resonance, Fourier transform infrared spectroscopy, field emission transmission electron microscopy, dynamic light scattering, and thermogravimetric analysis confirmed that the prepared BSA-Rh2 NPs were spherical, highly monodispersed, and stable in aqueous systems. In addition, the stability of NPs in terms of different time intervals, pHs, and temperatures (20°C-700°C) was analyzed. The results obtained with different pHs showed that the synthesized BSA-Rh2 NPs were stable in the physiological buffer (pH 7.4) for up to 8 days, but degraded under acidic conditions (pH 5.0) representing the pH inside tumor cells. Furthermore, comparative analysis of the water solubility of BSA-Rh2 NPs and standard Rh2 showed that the BSA nanocarrier enhanced the water solubility of Rh2. Moreover, in vitro cytotoxicity assays including cell viability assays and morphological analyses revealed that Rh2-entrapped BSA NPs, unlike the free Rh2, demonstrated better in vitro cell viability in HaCaT skin cell lines and that BSA enhanced the anticancer effect of Rh2 in A549 lung cell and HT29 colon cancer cell lines. Additionally, anti-inflammatory assay of BSA-Rh2 NPs and standard Rh2 performed using RAW264.7 cells revealed decreased lipopolysaccharide-induced nitric oxide production by BSA-Rh2 NPs. Collectively, the present study suggests that BSA can significantly enhance the therapeutic behavior of Rh2 by improving its solubility and stability in aqueous systems, and hence, BSA-Rh2 NPs may potentially be used as a ginsenoside delivery vehicle in cancer and

Highly conductive ribbons prepared by stick-slip assembly of organosoluble gold nanoparticles.

PubMed

Lawrence, Jimmy; Pham, Jonathan T; Lee, Dong Yun; Liu, Yujie; Crosby, Alfred J; Emrick, Todd

2014-02-25

Precisely positioning and assembling nanoparticles (NPs) into hierarchical nanostructures is opening opportunities in a wide variety of applications. Many techniques employed to produce hierarchical micrometer and nanoscale structures are limited by complex fabrication of templates and difficulties with scalability. Here we describe the fabrication and characterization of conductive nanoparticle ribbons prepared from surfactant-free organosoluble gold nanoparticles (Au NPs). We used a flow-coating technique in a controlled, stick-slip assembly to regulate the deposition of Au NPs into densely packed, multilayered structures. This affords centimeter-scale long, high-resolution Au NP ribbons with precise periodic spacing in a rapid manner, up to 2 orders-of-magnitude finer and faster than previously reported methods. These Au NP ribbons exhibit linear ohmic response, with conductivity that varies by changing the binding headgroup of the ligands. Controlling NP percolation during sintering (e.g., by adding polymer to retard rapid NP coalescence) enables the formation of highly conductive ribbons, similar to thermally sintered conductive adhesives. Hierarchical, conductive Au NP ribbons represent a promising platform to enable opportunities in sensing, optoelectronics, and electromechanical devices.

BMP-2 Derived Peptide and Dexamethasone Incorporated Mesoporous Silica Nanoparticles for Enhanced Osteogenic Differentiation of Bone Mesenchymal Stem Cells.

PubMed

Zhou, Xiaojun; Feng, Wei; Qiu, Kexin; Chen, Liang; Wang, Weizhong; Nie, Wei; Mo, Xiumei; He, Chuanglong

2015-07-29

Bone morphogenetic protein-2 (BMP-2), a growth factor that induces osteoblast differentiation and promotes bone regeneration, has been extensively investigated in bone tissue engineering. The peptides of bioactive domains, corresponding to residues 73-92 of BMP-2 become an alternative to reduce adverse side effects caused by the use of high doses of BMP-2 protein. In this study, BMP-2 peptide functionalized mesoporous silica nanoparticles (MSNs-pep) were synthesized by covalently grafting BMP-2 peptide on the surface of nanoparticles via an aminosilane linker, and dexamethasone (DEX) was then loaded into the channel of MSNs to construct nanoparticulate osteogenic delivery systems (DEX@MSNs-pep). The in vitro cell viability of MSNs-pep was tested with bone mesenchymal stem cells (BMSCs) exposure to different particle concentrations, revealing that the functionalized MSNs had better cytocompatibility than their bare counterparts, and the cellular uptake efficiency of MSNs-pep was remarkably larger than that of bare MSNs. The in vitro results also show that the MSNs-pep promoted osteogenic differentiation of BMSCs in terms of the levels of alkaline phosphatase (ALP) activity, calcium deposition, and expression of bone-related protein. Moreover, the osteogenic differentiation of BMSCs can be further enhanced by incorporating of DEX into MSNs-pep. After intramuscular implantation in rats for 3 weeks, the computed tomography (CT) images and histological examination indicate that this nanoparticulate osteogenic delivery system induces effective osteoblast differentiation and bone regeneration in vivo. Collectively, the BMP-2 peptide and DEX incorporated MSNs can act synergistically to enhance osteogenic differentiation of BMSCs, which have potential applications in bone tissue engineering.

Bespoke contrast-matched diblock copolymer nanoparticles enable the rational design of highly transparent Pickering double emulsions

NASA Astrophysics Data System (ADS)

Rymaruk, Matthew J.; Thompson, Kate L.; Derry, Matthew J.; Warren, Nicholas J.; Ratcliffe, Liam P. D.; Williams, Clive N.; Brown, Steven L.; Armes, Steven P.

2016-07-01

We report the preparation of highly transparent oil-in-water Pickering emulsions using contrast-matched organic nanoparticles. This is achieved via addition of judicious amounts of either sucrose or glycerol to an aqueous dispersion of poly(glycerol monomethacrylate)56-poly(2,2,2-trifluoroethyl methacrylate)500 [PGMA-PTFEMA] diblock copolymer nanoparticles prior to high shear homogenization with an equal volume of n-dodecane. The resulting Pickering emulsions comprise polydisperse n-dodecane droplets of 20-100 μm diameter and exhibit up to 96% transmittance across the visible spectrum. In contrast, control experiments using non-contrast-matched poly(glycerol monomethacrylate)56-poly(benzyl methacrylate)300 [PGMA56-PBzMA300] diblock copolymer nanoparticles as a Pickering emulsifier only produced conventional highly turbid emulsions. Thus contrast-matching of the two immiscible phases is a necessary but not sufficient condition for the preparation of highly transparent Pickering emulsions: it is essential to use isorefractive nanoparticles in order to minimize light scattering. Furthermore, highly transparent oil-in-water-in-oil Pickering double emulsions can be obtained by homogenizing the contrast-matched oil-in-water Pickering emulsion prepared using the PGMA56-PTFEMA500 nanoparticles with a contrast-matched dispersion of hydrophobic poly(lauryl methacrylate)39-poly(2,2,2-trifluoroethyl methacrylate)800 [PLMA39-PTFEMA800] diblock copolymer nanoparticles in n-dodecane. Finally, we show that an isorefractive oil-in-water Pickering emulsion enables fluorescence spectroscopy to be used to monitor the transport of water-insoluble small molecules (pyrene and benzophenone) between n-dodecane droplets. Such transport is significantly less efficient than that observed for the equivalent isorefractive surfactant-stabilized emulsion. Conventional turbid emulsions do not enable such a comparison to be made because the intense light scattering leads to substantial spectral

Corrosion resistance and cytocompatibility of biodegradable surgical magnesium alloy coated with hydrogenated amorphous silicon.

PubMed

Xin, Yunchang; Jiang, Jiang; Huo, Kaifu; Tang, Guoyi; Tian, Xiubo; Chu, Paul K

2009-06-01

The fast degradation rates in the physiological environment constitute the main limitation for the applications of surgical magnesium alloys as biodegradable hard-tissue implants. In this work, a stable and dense hydrogenated amorphous silicon coating (a-Si:H) with desirable bioactivity is deposited on AZ91 magnesium alloy using magnetron sputtering deposition. Raman spectroscopy and Fourier transform infrared spectroscopy reveal that the coating is mainly composed of hydrogenated amorphous silicon. The hardness of the coated alloy is enhanced significantly and the coating is quite hydrophilic as well. Potentiodynamic polarization results show that the corrosion resistance of the coated alloy is enhanced dramatically. In addition, the deterioration process of the coating in simulated body fluids is systematically investigated by open circuit potential evolution and electrochemical impedance spectroscopy. The cytocompatibility of the coated Mg is evaluated for the first time using hFOB1.19 cells and favorable biocompatibility is observed. 2008 Wiley Periodicals, Inc.

Humid Heat Autoclaving of Hybrid Nanoparticles Achieved by Decreased Nanoparticle Concentration and Improved Nanoparticle Stability Using Medium Chain Triglycerides as a Modifier.

PubMed

Gou, Jingxin; Chao, Yanhui; Liang, Yuheng; Zhang, Ning; He, Haibing; Yin, Tian; Zhang, Yu; Xu, Hui; Tang, Xing

2016-09-01

Humid heat autoclaving is a facile technique widely used in the sterilization of injections, but the high temperature employed would destroy nanoparticles composed of biodegradable polymers. The aim of this study was to investigate whether incorporation of medium chain triglycerides (MCT) could stabilize nanoparticles composed of poly (ethylene glycol)-b-polycaprolactone (PEG-b-PCL) during autoclaving (121°C, 10 min). Polymeric nanoparticles with different MCT contents were prepared by dialysis. Block copolymer degradation was studied by GPC. The critical aggregation concentrations of nanoparticles at different temperatures were determined using pyrene fluorescence. The size, morphology and weight averaged molecular weight of pristine/autoclaved nanoparticles were studied using DLS, TEM and SLS, respectively. Drug loading content and release profile were determined using RP-HPLC. The protecting effect of MCT on nanoparticles was dependent on the amount of MCT incorporated. Nanoparticles with high MCT contents, which assumed an emulsion-like morphology, showed reduced block copolymer degradation and particle disassociation after incubation at 100°C for 24 h. Nanoparticles with high MCT content showed the lowest critical aggregation concentration (CAC) under either room temperature or 60°C and the lowest particle concentration among all samples. And the particle size, drug loading content, physical stability and release profile of nanoparticles with high MCT contents remained nearly unchanged after autoclaving. Incorporation of high amount of MCT changed the morphology of PEG-b-PCL based nanoparticles to an emulsion-like structure and the nanoparticles prepared could withstand autoclaving due to improved particle stability and decreased particle concentration caused by MCT incorporation.

Highly Al-doped TiO{sub 2} nanoparticles produced by Ball Mill Method: structural and electronic characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santos, Desireé M. de los, E-mail: desire.delossantos@uca.es; Navas, Javier, E-mail: javier.navas@uca.es; Sánchez-Coronilla, Antonio

2015-10-15

Highlights: • Highly Al-doped TiO{sub 2} nanoparticles were synthesized using a Ball Mill Method. • Al doping delayed anatase to rutile phase transformation. • Al doping allow controlling the structural and electronic properties of nanoparticles. - Abstract: This study presents an easy method for synthesizing highly doped TiO{sub 2} nanoparticles. The Ball Mill method was used to synthesize pure and Al-doped titanium dioxide, with an atomic percentage up to 15.7 at.% Al/(Al + Ti). The samples were annealed at 773 K, 973 K and 1173 K, and characterized using ICP-AES, XRD, Raman spectroscopy, FT-IR, TG, STEM, XPS, and UV–vis spectroscopy.more » The effect of doping and the calcination temperature on the structure and properties of the nanoparticles were studied. The results show high levels of internal doping due to the substitution of Ti{sup 4+} ions by Al{sup 3+} in the TiO{sub 2} lattice. Furthermore, anatase to rutile transformation occurs at higher temperatures when the percentage of doping increases. Therefore, Al doping allows us to control the structural and electronic properties of the nanoparticle synthesized. So, it is possible to obtain nanoparticles with anatase as predominant phase in a higher range of temperature.« less

High-aluminum-affinity silica is a nanoparticle that seeds secondary aluminosilicate formation.

PubMed

Jugdaohsingh, Ravin; Brown, Andy; Dietzel, Martin; Powell, Jonathan J

2013-01-01

Despite the importance and abundance of aluminosilicates throughout our natural surroundings, their formation at neutral pH is, surprisingly, a matter of considerable debate. From our experiments in dilute aluminum and silica containing solutions (pH ~ 7) we previously identified a silica polymer with an extraordinarily high affinity for aluminium ions (high-aluminum-affinity silica polymer, HSP). Here, further characterization shows that HSP is a colloid of approximately 2.4 nm in diameter with a mean specific surface area of about 1,000 m(2) g(-1) and it competes effectively with transferrin for Al(III) binding. Aluminum binding to HSP strongly inhibited its decomposition whilst the reaction rate constant for the formation of the β-silicomolybdic acid complex indicated a diameter between 3.6 and 4.1 nm for these aluminum-containing nanoparticles. Similarly, high resolution microscopic analysis of the air dried aluminum-containing silica colloid solution revealed 3.9 ± 1.3 nm sized crystalline Al-rich silica nanoparticles (ASP) with an estimated Al:Si ratio of between 2 and 3 which is close to the range of secondary aluminosilicates such as imogolite. Thus the high-aluminum-affinity silica polymer is a nanoparticle that seeds early aluminosilicate formation through highly competitive binding of Al(III) ions. In niche environments, especially in vivo, this may serve as an alternative mechanism to polyhydroxy Al(III) species binding monomeric silica to form early phase, non-toxic aluminosilicates.

High-Aluminum-Affinity Silica Is a Nanoparticle That Seeds Secondary Aluminosilicate Formation

PubMed Central

Jugdaohsingh, Ravin; Brown, Andy; Dietzel, Martin; Powell, Jonathan J.

2013-01-01

Despite the importance and abundance of aluminosilicates throughout our natural surroundings, their formation at neutral pH is, surprisingly, a matter of considerable debate. From our experiments in dilute aluminum and silica containing solutions (pH ~ 7) we previously identified a silica polymer with an extraordinarily high affinity for aluminium ions (high-aluminum-affinity silica polymer, HSP). Here, further characterization shows that HSP is a colloid of approximately 2.4 nm in diameter with a mean specific surface area of about 1,000 m2 g-1 and it competes effectively with transferrin for Al(III) binding. Aluminum binding to HSP strongly inhibited its decomposition whilst the reaction rate constant for the formation of the β-silicomolybdic acid complex indicated a diameter between 3.6 and 4.1 nm for these aluminum-containing nanoparticles. Similarly, high resolution microscopic analysis of the air dried aluminum-containing silica colloid solution revealed 3.9 ± 1.3 nm sized crystalline Al-rich silica nanoparticles (ASP) with an estimated Al:Si ratio of between 2 and 3 which is close to the range of secondary aluminosilicates such as imogolite. Thus the high-aluminum-affinity silica polymer is a nanoparticle that seeds early aluminosilicate formation through highly competitive binding of Al(III) ions. In niche environments, especially in vivo, this may serve as an alternative mechanism to polyhydroxy Al(III) species binding monomeric silica to form early phase, non-toxic aluminosilicates. PMID:24349573

Superparamagnetic Nanoparticles as High Efficiency Magnetic Resonance Imaging T2 Contrast Agent.

PubMed

Sousa, Fernanda; Sanavio, Barbara; Saccani, Alessandra; Tang, Yun; Zucca, Ileana; Carney, Tamara M; Mastropietro, Alfonso; Jacob Silva, Paulo H; Carney, Randy P; Schenk, Kurt; Omrani, Arash O; Huang, Ping; Yang, Lin; Rønnow, Henrik M; Stellacci, Francesco; Krol, Silke

2017-01-18

Nanoparticle-based magnetic resonance imaging T 2 negative agents are of great interest, and much effort is devoted to increasing cell-loading capability while maintaining low cytotoxicity. Herein, two classes of mixed-ligand protected magnetic-responsive, bimetallic gold/iron nanoparticles (Au/Fe NPs) synthesized by a two-step method are presented. Their structure, surface composition, and magnetic properties are characterized. The two classes of sulfonated Au/Fe NPs, with an average diameter of 4 nm, have an average atomic ratio of Au to Fe equal to 7 or 8, which enables the Au/Fe NPs to be superparamagnetic with a blocking temperature of 56 K and 96 K. Furthermore, preliminary cellular studies reveal that both Au/Fe NPs show very limited toxicity. MRI phantom experiments show that r 2 /r 1 ratio of Au/Fe NPs is as high as 670, leading to a 66% reduction in T 2 relaxation time. These nanoparticles provide great versatility and potential for nanoparticle-based diagnostics and therapeutic applications and as imaging contrast agents.

In vitro cytocompatibility evaluation of chitosan/graphene oxide 3D scaffold composites designed for bone tissue engineering.

PubMed

Dinescu, Sorina; Ionita, Mariana; Pandele, Andreea Madalina; Galateanu, Bianca; Iovu, Horia; Ardelean, Aurel; Costache, Marieta; Hermenean, Anca

2014-01-01

Extensively studied nowadays, graphene oxide (GO) has a benefic effect on cell proliferation and differentiation, thus holding promise for bone tissue engineering (BTE) approaches. The aim of this study was not only to design a chitosan 3D scaffold improved with GO for optimal BTE, but also to analyze its physicochemical properties and to evaluate its cytocompatibility and ability to support cell metabolic activity and proliferation. Overall results show that the addition of GO in the scaffold's composition improved mechanical properties and pore formation and enhanced the bioactivity of the scaffold material for tissue engineering. The new developed CHT/GO 3 wt% scaffold could be a potential candidate for further in vitro and in vivo osteogenesis studies and BTE approaches.

A High-Yield Synthesis of Chalcopyrite CuIn S 2 Nanoparticles with Exceptional Size Control

DOE PAGES

Sun, Chivin; Gardner, Joseph S.; Shurdha, Endrit; ...

2009-01-01

We repormore » t high-yield and efficient size-controlled syntheses of Chalcopyrite CuIn S 2 nanoparticles by decomposing molecular single source precursors (SSPs) via microwave irradiation in the presence of 1,2-ethanedithiol at reaction temperatures as low as 100 ° C and times as short as 30 minutes. The nanoparticles sizes were 1.8 nm to 10.8 nm as reaction temperatures were varied from 100 ° C to 200 ° C with the bandgaps from 2.71 eV to 1.28 eV with good size control and high yields (64%–95%). The resulting nanoparticles were analyzed by XRD, UV-Vis, ICP-OES, XPS, SEM, EDS, and HRTEM. Titration studies by 1 H NMR using SSP 1 with 1,2-ethanedithiol and benzyl mercaptan were conducted to elucidate the formation of Chalcopyrite CuIn S 2 nanoparticles.« less

Highly Stable, Functional Hairy Nanoparticles and Biopolymers from Wood Fibers: Towards Sustainable Nanotechnology.

PubMed

Sheikhi, Amir; Yang, Han; Alam, Md Nur; van de Ven, Theo G M

2016-07-20

Nanoparticles, as one of the key materials in nanotechnology and nanomedicine, have gained significant importance during the past decade. While metal-based nanoparticles are associated with synthetic and environmental hassles, cellulose introduces a green, sustainable alternative for nanoparticle synthesis. Here, we present the chemical synthesis and separation procedures to produce new classes of hairy nanoparticles (bearing both amorphous and crystalline regions) and biopolymers based on wood fibers. Through periodate oxidation of soft wood pulp, the glucose ring of cellulose is opened at the C2-C3 bond to form 2,3-dialdehyde groups. Further heating of the partially oxidized fibers (e.g., T = 80 °C) results in three products, namely fibrous oxidized cellulose, sterically stabilized nanocrystalline cellulose (SNCC), and dissolved dialdehyde modified cellulose (DAMC), which are well separated by intermittent centrifugation and co-solvent addition. The partially oxidized fibers (without heating) were used as a highly reactive intermediate to react with chlorite for converting almost all aldehyde to carboxyl groups. Co-solvent precipitation and centrifugation resulted in electrosterically stabilized nanocrystalline cellulose (ENCC) and dicarboxylated cellulose (DCC). The aldehyde content of SNCC and consequently surface charge of ENCC (carboxyl content) were precisely controlled by controlling the periodate oxidation reaction time, resulting in highly stable nanoparticles bearing more than 7 mmol functional groups per gram of nanoparticles (e.g., as compared to conventional NCC bearing < 1 mmol functional group/g). Atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) attested to the rod-like morphology. Conductometric titration, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), dynamic light scattering (DLS), electrokinetic-sonic-amplitude (ESA) and acoustic attenuation

Investigating the oxidation mechanism of tantalum nanoparticles at high heating rates

NASA Astrophysics Data System (ADS)

DeLisio, Jeffery B.; Wang, Xizheng; Wu, Tao; Egan, Garth C.; Jacob, Rohit J.; Zachariah, Michael R.

2017-12-01

Reduced diffusion length scales and increased specific surface areas of nanosized metal fuels have recently demonstrated increased reaction rates for these systems, increasing their relevance in a wide variety of applications. The most commonly employed metal fuel, aluminum, tends to oxidize rapidly near its melting point (660 °C) in addition to undergoing a phase change of the nascent oxide shell. To further expand on the understanding of nanosized metal fuel oxidation, tantalum nanoparticles were studied due to their high melting point (3017 °C) in comparison to aluminum. Both traditional slow heating rate and in-situ high heating rate techniques were used to probe the oxidation of tantalum nanoparticles in oxygen containing environments in addition to nanothermite mixtures. When oxidized by gas phase oxygen, the oxide shell of the tantalum nanoparticles rapidly crystallized creating cracks that may attribute to enhanced oxygen diffusion into the particle. In the case of tantalum based nanothermites, oxide shell crystallization was shown to induce reactive sintering with the metal oxide resulting in a narrow range of ignition temperatures independent of the metal oxide used. The oxidation mechanism was modeled using the Deal-Grove model to extract rate parameters, and theoretical burn times for tantalum based nanocomposites were calculated.

RGD-functionalized ultrasmall iron oxide nanoparticles for targeted T1-weighted MR imaging of gliomas

NASA Astrophysics Data System (ADS)

Luo, Yu; Yang, Jia; Yan, Yu; Li, Jingchao; Shen, Mingwu; Zhang, Guixiang; Mignani, Serge; Shi, Xiangyang

2015-08-01

We report a convenient approach to prepare ultrasmall Fe3O4 nanoparticles (NPs) functionalized with an arginylglycylaspartic acid (RGD) peptide for in vitro and in vivo magnetic resonance (MR) imaging of gliomas. In our work, stable sodium citrate-stabilized Fe3O4 NPs were prepared by a solvothermal route. Then, the carboxylated Fe3O4 NPs stabilized with sodium citrate were conjugated with polyethylene glycol (PEG)-linked RGD. The formed ultrasmall RGD-functionalized nanoprobe (Fe3O4-PEG-RGD) was fully characterized using different techniques. We show that these Fe3O4-PEG-RGD particles with a size of 2.7 nm are water-dispersible, stable, cytocompatible and hemocompatible in a given concentration range, and display targeting specificity to glioma cells overexpressing αvβ3 integrin in vitro. With the relatively high r1 relaxivity (r1 = 1.4 mM-1 s-1), the Fe3O4-PEG-RGD particles can be used as an efficient nanoprobe for targeted T1-weighted positive MR imaging of glioma cells in vitro and the xenografted tumor model in vivo via an active RGD-mediated targeting pathway. The developed RGD-functionalized Fe3O4 NPs may hold great promise to be used as a nanoprobe for targeted T1-weighted MR imaging of different αvβ3 integrin-overexpressing cancer cells or biological systems.We report a convenient approach to prepare ultrasmall Fe3O4 nanoparticles (NPs) functionalized with an arginylglycylaspartic acid (RGD) peptide for in vitro and in vivo magnetic resonance (MR) imaging of gliomas. In our work, stable sodium citrate-stabilized Fe3O4 NPs were prepared by a solvothermal route. Then, the carboxylated Fe3O4 NPs stabilized with sodium citrate were conjugated with polyethylene glycol (PEG)-linked RGD. The formed ultrasmall RGD-functionalized nanoprobe (Fe3O4-PEG-RGD) was fully characterized using different techniques. We show that these Fe3O4-PEG-RGD particles with a size of 2.7 nm are water-dispersible, stable, cytocompatible and hemocompatible in a given concentration

Synthesis of multivalent sialyllactosamine-carrying glyco-nanoparticles with high affinity to the human influenza virus hemagglutinin.

PubMed

Ogata, Makoto; Umemura, Seiichiro; Sugiyama, Naohiro; Kuwano, Natsuki; Koizumi, Ami; Sawada, Tadakazu; Yanase, Michiyo; Takaha, Takeshi; Kadokawa, Jun-Ichi; Usui, Taichi

2016-11-20

A series of multivalent sialoglyco-conjugated nanoparticles were efficiently synthesized by using highly-branched α-glucuronic acid-linked cyclic dextrins (GlcA-HBCD) as a backbone. The sialoglycoside-moieties, with varying degrees of substitution, could be incorporated onto the preformed nanoparticles. These synthesized particles, which are highly soluble in aqueous solution, were shown to have a spherical nanostructure with a diameter of approximately 15nm. The interactions of the sialoglyco-nanoparticles (Neu5Acα2,6LacNAc-GlcA-HBCDs) with human influenza virus strain A/Beijing/262/95 (H1N1) were investigated using a hemagglutination inhibition assay. The sialoglyco-nanoparticle, in which the number of sialic acid substitution is 30, acted as a powerful inhibitor of virus binding activity. We show that both distance and multiplicity of effective ligand-virus formation play important roles in enhancing viral inhibition. Our results indicate that the GlcA-HBCD backbone can be used as a novel spherical nanocluster material for preparing a variety of glyco-nanoparticles to facilitate molecular recognition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Highly stable silica-coated manganese ferrite nanoparticles as high-efficacy T2 contrast agents for magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Ahmad, Ashfaq; Bae, Hongsub; Rhee, Ilsu

2018-05-01

Highly stable silica-coated manganese ferrite nanoparticles were fabricated for application as magnetic resonance imagining (MRI) contrast agents. The manganese ferrite nanoparticles were synthesized using a hydrothermal technique and coated with silica. The particle size was investigated using transmission electron microscopy and was found to be 40-60 nm. The presence of the silica coating on the particle surface was confirmed by Fourier transform infrared spectroscopy. The crystalline structure was investigated by X-ray diffraction, and the particles were revealed to have an inverse spinel structure. Superparamagnetism was confirmed by the magnetic hysteresis curves obtained using a vibrating sample magnetometer. The efficiency of the MRI contrast agents was investigated by using aqueous solutions of the particles in a 4.7 T MRI scanner. The T1 and T2 relaxivities of the particles were 1.42 and 60.65 s-1 mM-1, respectively, in water. The ratio r2/r1 was 48.91, confirming that the silica-coated manganese ferrite nanoparticles were suitable high-efficacy T2 contrast agents.

Highly Sensitive DNA Sensor Based on Upconversion Nanoparticles and Graphene Oxide.

PubMed

Alonso-Cristobal, P; Vilela, P; El-Sagheer, A; Lopez-Cabarcos, E; Brown, T; Muskens, O L; Rubio-Retama, J; Kanaras, A G

2015-06-17

In this work we demonstrate a DNA biosensor based on fluorescence resonance energy transfer (FRET) between NaYF4:Yb,Er nanoparticles and graphene oxide (GO). Monodisperse NaYF4:Yb,Er nanoparticles with a mean diameter of 29.1 ± 2.2 nm were synthesized and coated with a SiO2 shell of 11 nm, which allowed the attachment of single strands of DNA. When these DNA-functionalized NaYF4:Yb,Er@SiO2 nanoparticles were in the proximity of the GO surface, the π-π stacking interaction between the nucleobases of the DNA and the sp(2) carbons of the GO induced a FRET fluorescence quenching due to the overlap of the fluorescence emission of the NaYF4:Yb,Er@SiO2 and the absorption spectrum of GO. By contrast, in the presence of the complementary DNA strands, the hybridization leads to double-stranded DNA that does not interact with the GO surface, and thus the NaYF4:Yb,Er@SiO2 nanoparticles remain unquenched and fluorescent. The high sensitivity and specificity of this sensor introduces a new method for the detection of DNA with a detection limit of 5 pM.

SERS-active silver nanoparticle aggregates produced in high-iron float glass by ion exchange process

NASA Astrophysics Data System (ADS)

Karvonen, L.; Chen, Y.; Säynätjoki, A.; Taiviola, K.; Tervonen, A.; Honkanen, S.

2011-11-01

Silver nanoparticles were produced in iron containing float glasses by silver-sodium ion exchange and post-annealing. In particular, the effect of the concentration and the oxidation state of iron in the host glass on the nanoparticle formation was studied. After the nanoparticle fabrication process, the samples were characterized by optical absorption measurements. The samples were etched to expose nanoparticle aggregates on the surface, which were studied by optical microscopy and scanning electron microscopy. The SERS-activity of these glass samples was demonstrated and compared using a dye molecule Rhodamine 6G (R6G) as an analyte. The importance of the iron oxidation level for reduction process is discussed. The glass with high concentration of Fe 2+ ions was found to be superior in SERS applications of silver nanoparticles. The optimal surface features in terms of SERS enhancement are also discussed.

Bismuth nanoparticle decorating graphite felt as a high-performance electrode for an all-vanadium redox flow battery.

PubMed

Li, Bin; Gu, Meng; Nie, Zimin; Shao, Yuyan; Luo, Qingtao; Wei, Xiaoliang; Li, Xiaolin; Xiao, Jie; Wang, Chongmin; Sprenkle, Vincent; Wang, Wei

2013-03-13

Employing electrolytes containing Bi(3+), bismuth nanoparticles are synchronously electrodeposited onto the surface of a graphite felt electrode during operation of an all-vanadium redox flow battery (VRFB). The influence of the Bi nanoparticles on the electrochemical performance of the VRFB is thoroughly investigated. It is confirmed that Bi is only present at the negative electrode and facilitates the redox reaction between V(II) and V(III). However, the Bi nanoparticles significantly improve the electrochemical performance of VRFB cells by enhancing the kinetics of the sluggish V(II)/V(III) redox reaction, especially under high power operation. The energy efficiency is increased by 11% at high current density (150 mA·cm(-2)) owing to faster charge transfer as compared with one without Bi. The results suggest that using Bi nanoparticles in place of noble metals offers great promise as high-performance electrodes for VRFB application.

Hyaluronic acid-modified manganese-chelated dendrimer-entrapped gold nanoparticles for the targeted CT/MR dual-mode imaging of hepatocellular carcinoma

NASA Astrophysics Data System (ADS)

Wang, Ruizhi; Luo, Yu; Yang, Shuohui; Lin, Jiang; Gao, Dongmei; Zhao, Yan; Liu, Jinguo; Shi, Xiangyang; Wang, Xiaolin

2016-09-01

Hepatocellular carcinoma (HCC) is the most common malignant tumor of the liver. The early and effective diagnosis has always been desired. Herein, we present the preparation and characterization of hyaluronic acid (HA)-modified, multifunctional nanoparticles (NPs) targeting CD44 receptor-expressing cancer cells for computed tomography (CT)/magnetic resonance (MR) dual-mode imaging. We first modified amine-terminated generation 5 poly(amidoamine) dendrimers (G5.NH2) with an Mn chelator, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), fluorescein isothiocyanate (FI), and HA. Then, gold nanoparticles (AuNPs) were entrapped within the above raw product, denoted as G5.NH2-FI-DOTA-HA. The designed multifunctional NPs were formed after further Mn chelation and purification and were denoted as {(Au0)100G5.NH2-FI-DOTA(Mn)-HA}. These NPs were characterized via several different techniques. We found that the {(Au0)100G5.NH2-FI-DOTA(Mn)-HA} NPs exhibited good water dispersibility, stability under different conditions, and cytocompatibility within a given concentration range. Because both AuNPs and Mn were present in the product, {(Au0)100G5.NH2-FI-DOTA(Mn)-HA} displayed a high X-ray attenuation intensity and favorable r1 relaxivity, which are advantageous properties for targeted CT/MR dual-mode imaging. This approach was used to image HCC cells in vitro and orthotopically transplanted HCC tumors in a unique in vivo model through the CD44 receptor-mediated endocytosis pathway. This work introduces a novel strategy for preparing multifunctional NPs via dendrimer nanotechnology.

High-Density Lipoproteins (HDL) – Nature’s Multi-Functional Nanoparticles

PubMed Central

Kuai, Rui; Li, Dan; Chen, Y. Eugene; Moon, James J.; Schwendeman, Anna

2016-01-01

High-density lipoproteins (HDL) are endogenous nanoparticles involved in the transport and metabolism of cholesterol, phospholipids, and triglycerides. HDL is well known as the ―good‖ cholesterol because it not only removes excess cholesterol from atherosclerotic plaques but also has anti-inflammatory and anti-oxidative properties, which protect the cardiovascular system. Circulating HDL also transports endogenous proteins, vitamins, hormones, and microRNA to various organs. Compared with other synthetic nanocarriers, such as liposomes, micelles, inorganic and polymeric nanoparticles, HDL has unique features that allow them to deliver cargo to specific targets more efficiently. These attributes include their ultra-small size (8-12 nm in diameter), high tolerability in humans (up to 8 g of protein per infusion), long circulating half-life (12-24 hours), and intrinsic targeting properties to different recipient cells. Various recombinant ApoA proteins and ApoA mimetic peptides have been recently developed for the preparation of reconstituted HDL that exhibits properties similar to endogenous HDL and has a potential for industrial scale-up. In this review, we will summarize: a) clinical pharmacokinetics and safety of reconstituted HDL products, b) comparison of HDL with inorganic and other organic nanoparticles, c) the rationale for using HDL as drug delivery vehicles for important therapeutic indications, d) the current state-of-the-art in HDL production, and e) HDL-based drug delivery strategies for small molecules, peptides/proteins, nucleic acids, and imaging agents targeted to various organs. PMID:26889958

High reactive sulphide chemically supported on silica surface to prepare functional nanoparticle

NASA Astrophysics Data System (ADS)

Chen, Lijuan; Guo, Xiaohui; Jia, Zhixin; Tang, Yuhan; Wu, Lianghui; Luo, Yuanfang; Jia, Demin

2018-06-01

A solid-phase preparation method was applied to obtain a novel, green and effective functional nanoparticle, silica-supported sulfur monochloride (silica-s-S2Cl2), by the chemical reaction between chlorine atom and silicon hydroxyl on the silica surface. Through this chemical reaction, silica surface supported with high content of sulfur, and the functional nanoparticles can not only vulcanize the rubber instead of sulfur or other vulcanizing agent with high performance, but also improve the filler-rubber interaction as a modifier due to the improved modification effect. 29Si NMR, Raman spectroscopy, Element analysis and TGA confirm that the sulfur monochloride is chemically bonded on the silica surface. Cure properties measurement, morphology of filler dispersion, mechanical properties measurement, immobilized polymer layer and oxidation induction time increment together show that the novel vulcanizing agent silica-s-S2Cl2 instead of sulfur in rubber vulcanization gives rise to significant improvement in the crosslinking density and the interfacial adhesion between silica particles and the rubber matrix, which is on account of the promoted vulcanizing on the functional silica nanoparticles surface with the supported sulfur.

Magnetic core shell nanoparticles trapping in a microdevice generating high magnetic gradient.

PubMed

Teste, Bruno; Malloggi, Florent; Gassner, Anne-Laure; Georgelin, Thomas; Siaugue, Jean-Michel; Varenne, Anne; Girault, Hubert; Descroix, Stéphanie

2011-03-07

Magnetic core shell nanoparticles (MCSNPs) 30 nm diameter with a magnetic weight of 10% are usually much too small to be trapped in microfluidic systems using classical external magnets. Here, a simple microchip for efficient MCSNPs trapping and release is presented. It comprises a bed of micrometric iron beads (6-8 μm diameter) packed in a microchannel against a physical restriction and presenting a low dead volume of 0.8 nL. These beads of high magnetic permeability are used to focus magnetic field lines from an external permanent magnet and generate local high magnetic gradients. The nanoparticles magnetic trap has been characterised both by numerical simulations and fluorescent MCSNPs imaging. Numerical simulations have been performed to map both the magnetic flux density and the magnetic force, and showed that MCSNPs are preferentially trapped at the iron bead magnetic poles where the magnetic force is increased by 3 orders of magnitude. The trapping efficiency was experimentally determined using fluorescent MCSNPs for different flow rates, different iron beads and permanent magnet positions. At a flow rate of 100 μL h(-1), the nanoparticles trapping/release can be achieved within 20 s with a preconcentration factor of 4000.

The preparation, cytocompatibility and antimicrobial property of micro/nano structural titanium loading alginate and antimicrobial peptide

NASA Astrophysics Data System (ADS)

Liu, Zhiyuan; Zhong, Mou; Sun, Yuhua; Chen, Junhong; Feng, Bo

2018-03-01

Titanium with hybrid microporous/nanotubes (TMNT) structure on its surface was fabricated by acid etching and subsequently anodization at different voltages. Bovine lactoferricin, a kind of antimicrobial peptide, and sodium alginate (NaAlg) were loaded onto titanium surface through layer by layer assembly. The drug release, cytocompatibility and antimicrobial property against S.aureus and E.coil were studied by release experiment, osteoblast and bacterial cultures. Results indicated that samples with nanotubes of bigger diameter carried more drugs and had better biocompatibility, and drug-loaded samples acquired better biocompatibility compared with drug-free samples. Furthermore, the drug-loaded samples exhibited good initial antimicrobial property, but weak long-term antimicrobial property. Therefore, drug-loaded titanium with micro/nano structure, especially, of big diameter nanotubes, could be a promise material for medical implants, such as internal/external fixation devices.

Human-like collagen protein-coated magnetic nanoparticles with high magnetic hyperthermia performance and improved biocompatibility

NASA Astrophysics Data System (ADS)

Liu, Xiaoli; Zhang, Huan; Chang, Le; Yu, Baozhi; Liu, Qiuying; Wu, Jianpeng; Miao, Yuqing; Ma, Pei; Fan, Daidi; Fan, Haiming

2015-01-01

Human-like collagen (HLC)-coated monodispersed superparamagnetic Fe3O4 nanoparticles have been successfully prepared to investigate its effect on heat induction property and cell toxicity. After coating of HLC, the sample shows a faster rate of temperature increase under an alternating magnetic field although it has a reduced saturation magnetization. This is most probably a result of the effective heat conduction and good colloid stability due to the high charge of HLC on the surface. In addition, compared with Fe3O4 nanoparticles before coating with HLC, HLC-coated Fe3O4 nanoparticles do not induce notable cytotoxic effect at higher concentration which indicates that HLC-coated Fe3O4 nanoparticles has improved biocompatibility. Our results clearly show that Fe3O4 nanoparticles after coating with HLC not only possess effective heat induction for cancer treatment but also have improved biocompatibility for biomedicine applications.

Curcumin modified silver nanoparticles for highly efficient inhibition of respiratory syncytial virus infection

NASA Astrophysics Data System (ADS)

Yang, Xiao Xi; Li, Chun Mei; Huang, Cheng Zhi

2016-01-01

Interactions between nanoparticles and viruses have attracted increasing attention due to the antiviral activity of nanoparticles and the resulting possibility to be employed as biomedical interventions. In this contribution, we developed a very simple route to prepare uniform and stable silver nanoparticles (AgNPs) with antiviral properties by using curcumin, which is a member of the ginger family isolated from rhizomes of the perennial herb Curcuma longa and has a wide range of biological activities like antioxidant, antifungal, antibacterial and anti-inflammatory effects, and acts as reducing and capping agents in this synthetic route. The tissue culture infectious dose (TCID50) assay showed that the curcumin modified silver nanoparticles (cAgNPs) have a highly efficient inhibition effect against respiratory syncytial virus (RSV) infection, giving a decrease of viral titers about two orders of magnitude at the concentration of cAgNPs under which no toxicity was found to the host cells. Mechanism investigations showed that cAgNPs could prevent RSV from infecting the host cells by inactivating the virus directly, indicating that cAgNPs are a novel promising efficient virucide for RSV.Interactions between nanoparticles and viruses have attracted increasing attention due to the antiviral activity of nanoparticles and the resulting possibility to be employed as biomedical interventions. In this contribution, we developed a very simple route to prepare uniform and stable silver nanoparticles (AgNPs) with antiviral properties by using curcumin, which is a member of the ginger family isolated from rhizomes of the perennial herb Curcuma longa and has a wide range of biological activities like antioxidant, antifungal, antibacterial and anti-inflammatory effects, and acts as reducing and capping agents in this synthetic route. The tissue culture infectious dose (TCID50) assay showed that the curcumin modified silver nanoparticles (cAgNPs) have a highly efficient inhibition

Biosynthesis of spherical and highly stable gold nanoparticles using Ferulago Angulata aqueous extract: dual role of extract

NASA Astrophysics Data System (ADS)

Alizadeh, A.; Parsafar, S.; Khodaei, M. M.

2017-03-01

A biocompatible method for synthesizing of highly disperses gold nanoparticles using Ferulago Angulata leaf extract has been developed. It has been shown that leaf extract acts as reducing and coating agent. Various spectroscopic and electron microscopic techniques were employed for the structural characterization of the prepared nanoparticles. The biosynthesized particles were identified as elemental gold with spherical morphology, narrow size distribution (ranged 9.2-17.5 nm) with high stability. Also, the effect of initial ratio of precursors, temperature and time of reaction on the size and morphology of the nanoparticles was studied in more detail. It was observed that varying these parameters provides an accessible remote control on the size and morphology of nanoparticles. The uniqueness of this procedure lies in its cleanliness using no extra surfactant, reducing agent or any capping agent.

High-energy x-ray diffraction from surfaces and nanoparticles

NASA Astrophysics Data System (ADS)

Hejral, U.; Müller, P.; Shipilin, M.; Gustafson, J.; Franz, D.; Shayduk, R.; Rütt, U.; Zhang, C.; Merte, L. R.; Lundgren, E.; Vonk, V.; Stierle, A.

2017-11-01

High-energy surface-sensitive x-ray diffraction (HESXRD) is a powerful high-energy photon technique (E > 70 keV) that has in recent years proven to allow a fast data acquisition for the 3D structure determination of surfaces and nanoparticles under in situ and operando conditions. The use of a large-area detector facilitates the direct collection of nearly distortion-free diffraction patterns over a wide q range, including crystal truncation rods perpendicular to the surface and large-area reciprocal space maps from epitaxial nanoparticles, which is not possible in the conventional low-photon energy approach (E =10 -20 keV ). Here, we present a comprehensive mathematical approach, explaining the working principle of HESXRD for both single-crystal surfaces and epitaxial nanostructures on single-crystal supports. The angular calculations used in conventional crystal truncation rod measurements at low-photon energies are adopted for the high-photon-energy regime, illustrating why and to which extent large reciprocal-space areas can be probed in stationary geometry with fixed sample rotation. We discuss how imperfections such as mosaicity and finite domain size aid in sampling a substantial part of reciprocal space without the need of rotating the sample. An exact account is given of the area probed in reciprocal space using such a stationary mode, which is essential for in situ or operando time-resolved experiments on surfaces and nanostructures.

Highly stable molybdenum dioxide nanoparticles with strong plasmon resonance are promising in photothermal cancer therapy.

PubMed

Liu, Wei; Li, Xinshi; Li, Wentao; Zhang, Qiqi; Bai, Hua; Li, Junfang; Xi, Guangcheng

2018-05-01

Photothermal therapy (PTT) is one of promising cancer therapy with high efficiency and minimal invasiveness. Exploiting of perfect PTT agent is vital to improve the therapy. In this study, a new type of bow tie-like molybdenum dioxide (MoO 2 ) nanoparticles was successfully synthesized. These nanobow-ties had strong localized surface plasmon resonance (SPR) effect from visible to near infrared regions, and exhibited ultrahigh chemical stability. They could not only withstand high temperature heating without oxidation, but also resist the corrosion of strong acid and alkali. Meanwhile, the MoO 2 nanoparticles were highly stable in protein-containing biological medium, though they partly degraded in PBS solution. Both in vivo and in vitro experiments indicated that they exhibited inappreciable toxicity. Under illumination of near infrared laser, they showed excellent PTT effect, as revealed by significant inhibition of cancer cell viability in vitro and efficient destruction in tumor tissue growth in vivo. These MoO 2 nanoparticles possessed highly chemical stability and low toxicity with high PTT efficiency, thus promising them high potential as nanoagent in cancer treatment. Copyright © 2018. Published by Elsevier Ltd.

Development of polymeric-cationic peptide composite nanoparticles, a nanoparticle-in-nanoparticle system for controlled gene delivery.

PubMed

Jain, Arvind K; Massey, Ashley; Yusuf, Helmy; McDonald, Denise M; McCarthy, Helen O; Kett, Vicky L

2015-01-01

We report the formulation of novel composite nanoparticles that combine the high transfection efficiency of cationic peptide-DNA nanoparticles with the biocompatibility and prolonged delivery of polylactic acid-polyethylene glycol (PLA-PEG). The cationic cell-penetrating peptide RALA was used to condense DNA into nanoparticles that were encapsulated within a range of PLA-PEG copolymers. The composite nanoparticles produced exhibited excellent physicochemical properties including size <200 nm and encapsulation efficiency >80%. Images of the composite nanoparticles obtained with a new transmission electron microscopy staining method revealed the peptide-DNA nanoparticles within the PLA-PEG matrix. Varying the copolymers modulated the DNA release rate >6 weeks in vitro. The best formulation was selected and was able to transfect cells while maintaining viability. The effect of transferrin-appended composite nanoparticles was also studied. Thus, we have demonstrated the manufacture of composite nanoparticles for the controlled delivery of DNA.

Development of polymeric–cationic peptide composite nanoparticles, a nanoparticle-in-nanoparticle system for controlled gene delivery

PubMed Central

Jain, Arvind K; Massey, Ashley; Yusuf, Helmy; McDonald, Denise M; McCarthy, Helen O; Kett, Vicky L

2015-01-01

We report the formulation of novel composite nanoparticles that combine the high transfection efficiency of cationic peptide-DNA nanoparticles with the biocompatibility and prolonged delivery of polylactic acid–polyethylene glycol (PLA-PEG). The cationic cell-penetrating peptide RALA was used to condense DNA into nanoparticles that were encapsulated within a range of PLA-PEG copolymers. The composite nanoparticles produced exhibited excellent physicochemical properties including size <200 nm and encapsulation efficiency >80%. Images of the composite nanoparticles obtained with a new transmission electron microscopy staining method revealed the peptide-DNA nanoparticles within the PLA-PEG matrix. Varying the copolymers modulated the DNA release rate >6 weeks in vitro. The best formulation was selected and was able to transfect cells while maintaining viability. The effect of transferrin-appended composite nanoparticles was also studied. Thus, we have demonstrated the manufacture of composite nanoparticles for the controlled delivery of DNA. PMID:26648722

Peptide-laden mesoporous silica nanoparticles with promoted bioactivity and osteo-differentiation ability for bone tissue engineering.

PubMed

Luo, Zuyuan; Deng, Yi; Zhang, Ranran; Wang, Mengke; Bai, Yanjie; Zhao, Qiang; Lyu, Yalin; Wei, Jie; Wei, Shicheng

2015-07-01

Combination of mesoporous silica materials and bioactive factors is a promising niche-mimetic solution as a hybrid bone substitution for bone tissue engineering. In this work, we have synthesized biocompatible silica-based nanoparticles with abundant mesoporous structure, and incorporated bone-forming peptide (BFP) derived from bone morphogenetic protein-7 (BMP-7) into the mesoporous silica nanoparticles (MSNs) to obtain a slow-release system for osteogenic factor delivery. The chemical characterization demonstrates that the small osteogenic peptide is encapsulated in the mesoporous successfully, and the nitrogen adsorption-desorption isotherms suggest that the peptide encapsulation has no influence on mesoporous structure of MSNs. In the cell experiment, the peptide-laden MSNs (p-MSNs) show higher MG-63 cell proliferation, spreading and alkaline phosphatase (ALP) activity than the bare MSNs, indicating good in vitro cytocompatibility. Simultaneously, the osteogenesis-related proteins expression and calcium mineral deposition disclose enhanced osteo-differentiation of human mesenchymal stem cells (hMSCs) under the stimulation of the p-MSNs, confirming that BFP released from MSNs could significantly promote the osteogenic differentiation of hMSCs, especially at 500μg/mL of p-MSNs concentration. The peptide-modified MSNs with better bioactivity and osteogenic differentiation make it a potential candidate as bioactive material for bone repairing, bone regeneration, and bio-implant coating applications. Copyright © 2015 Elsevier B.V. All rights reserved.

High rate performance supercapacitor based on Nb2O5 nanoparticles

NASA Astrophysics Data System (ADS)

Ahmed, Sultan; Ahmed, Ahsan; Rafat, M.

2018-05-01

In the present communication, we report the successful preparation of Nb2O5 nanoparticles from precursor NbCl5 using hydrothermal method, followed by thermal annealing. The surface morphology of the as-prepared material was studied using scanning electron microscopy (SEM) while crystal structure and vibrational response was characterized using X-ray diffraction (XRD) and Raman spectroscopy. The observed results indicate the successful synthesis of Nb2O5 nanoparticles. The electrochemical properties of the material was investigated in two-electrode assembly in 1 M LiClO4 solution using the techniques of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Both EIS and CV studies show high rate performance of the assembled supercapacitor cells. Fabricated cell offers low response time (˜17.1 ms), and the shape of CV pattern remains almost rectangular, even for high scan rates (˜20 V s-1).

Metal matrix-metal nanoparticle composites with tunable melting temperature and high thermal conductivity for phase-change thermal storage.

PubMed

Liu, Minglu; Ma, Yuanyu; Wu, Hsinwei; Wang, Robert Y

2015-02-24

Phase-change materials (PCMs) are of broad interest for thermal storage and management applications. For energy-dense storage with fast thermal charging/discharging rates, a PCM should have a suitable melting temperature, large enthalpy of fusion, and high thermal conductivity. To simultaneously accomplish these traits, we custom design nanocomposites consisting of phase-change Bi nanoparticles embedded in an Ag matrix. We precisely control nanoparticle size, shape, and volume fraction in the composite by separating the nanoparticle synthesis and nanocomposite formation steps. We demonstrate a 50-100% thermal energy density improvement relative to common organic PCMs with equivalent volume fraction. We also tune the melting temperature from 236-252 °C by varying nanoparticle diameter from 8.1-14.9 nm. Importantly, the silver matrix successfully prevents nanoparticle coalescence, and no melting changes are observed during 100 melt-freeze cycles. The nanocomposite's Ag matrix also leads to very high thermal conductivities. For example, the thermal conductivity of a composite with a 10% volume fraction of 13 nm Bi nanoparticles is 128 ± 23 W/m-K, which is several orders of magnitude higher than typical thermal storage materials. We complement these measurements with calculations using a modified effective medium approximation for nanoscale thermal transport. These calculations predict that the thermal conductivity of composites with 13 nm Bi nanoparticles varies from 142 to 47 W/m-K as the nanoparticle volume fraction changes from 10 to 35%. Larger nanoparticle diameters and/or smaller nanoparticle volume fractions lead to larger thermal conductivities.

Highly sensitive free radical detection by nitrone-functionalized gold nanoparticles

NASA Astrophysics Data System (ADS)

Du, Libo; Huang, Saipeng; Zhuang, Qianfen; Jia, Hongying; Rockenbauer, Antal; Liu, Yangping; Liu, Ke Jian; Liu, Yang

2014-01-01

The detection of free radicals and related species has attracted significant attention in recent years because of their critical roles in physiological and pathological processes. Among the methods for the detection of free radicals, electron spin resonance (ESR) coupled with the use of the spin trapping technique has been an effective approach for characterization and quantification of these species due to its high specificity. However, its application in biological systems, especially in in vivo systems, has been greatly limited partially due to the low reaction rate between the currently available spin traps with biological radicals. To overcome this drawback, we herein report the first example of nitrone functionalized gold nanoparticles (Au@EMPO) as highly efficient spin traps in which the thiolated EMPO (2-(ethoxycarbonyl)-2-methyl-3,4-dihydro-2H-pyrrole 1-oxide) derivative was self-assembled on gold nanoparticles. Kinetic studies showed that Au@EMPO has a 137-fold higher reaction rate constant with &z.rad;OH than PBN (N-tert-butyl-α-phenylnitrone). Owing to the high rate of trapping &z.rad;OH by Au@EMPO as well as the high stability of the resulting spin adduct (t1/2 ~ 56 min), Au@EMPO affords 124-fold higher sensitivity for &z.rad;OH than EMPO. Thus, this new nanospin trap shows great potential in trapping the important radicals such as &z.rad;OH in various biological systems and provides a novel strategy to design spin traps with much improved properties.The detection of free radicals and related species has attracted significant attention in recent years because of their critical roles in physiological and pathological processes. Among the methods for the detection of free radicals, electron spin resonance (ESR) coupled with the use of the spin trapping technique has been an effective approach for characterization and quantification of these species due to its high specificity. However, its application in biological systems, especially in in vivo systems

Deep tissue penetration of nanoparticles using pulsed-high intensity focused ultrasound

NASA Astrophysics Data System (ADS)

You, Dong Gil; Yoon, Hong Yeol; Jeon, Sangmin; Um, Wooram; Son, Sejin; Park, Jae Hyung; Kwon, Ick Chan; Kim, Kwangmeyung

2017-11-01

Recently, ultrasound (US)-based drug delivery strategies have received attention to improve enhanced permeation and retention (EPR) effect-based passive targeting efficiency of nanoparticles in vitro and in vivo conditions. Among the US treatment techniques, pulsed-high intensity focused ultrasound (pHIFU) have specialized for improving tissue penetration of various macromolecules and nanoparticles without irreversible tissue damages. In this study, we have demonstrated that pHIFU could be utilized to improve tissue penetration of fluorescent dye-labeled glycol chitosan nanoparticles (FCNPs) in femoral tissue of mice. pHIFU could improve blood flow of the targeted-blood vessel in femoral tissue. In addition, tissue penetration of FCNPs was specifically increased 5.7-, 8- and 9.3-folds than that of non-treated (0 W pHIFU) femoral tissue, when the femoral tissue was treated with 10, 20 and 50 W of pHIFU, respectively. However, tissue penetration of FCNPs was significantly reduced after 3 h post-pHIFU treatment (50 W). Because overdose (50 W) of pHIFU led to irreversible tissue damages, including the edema and chapped red blood cells. These overall results support that pHIFU treatment can enhance the extravasation and tissue penetration of FCNPs as well as induce irreversible tissue damages. We expect that our results can provide advantages to optimize pHIFU-mediated delivery strategy of nanoparticles for further clinical applications.

Synthesis and morphological examination of high-purity Ca(OH)2 nanoparticles suitable to consolidate porous surfaces

NASA Astrophysics Data System (ADS)

Madrid, Juan Antonio; Lanzón, Marcos

2017-12-01

Adequate synthetic methods to obtain pure Ca(OH)2 nanoparticles are scarcely documented in the literature. This paper presents a complete methodology to obtain highly-pure Ca(OH)2 nanoparticles that are appropriate for strengthening heritage materials. The precipitation synthesis was operated in controlled atmosphere to avoid carbonation by atmospheric CO2. A complete purification method was developed to eliminate the sodium chloride generated in the reaction. Several analytical techniques, such as electrical conductivity, pH, ion chromatography, X-ray diffraction (XRD) and thermogravimetric analysis coupled to mass spectrometry (TGA-MS) were used to analyse both the aqueous medium and solid phase. The amount of material obtained in the synthesis (yield) was quantified throughout the purification procedure. The influence of temperature on the nanoparticles' size and stability was studied by transmission electron microscopy (HRTEM) and sedimentation tests (light scattering). It was found that the synthesis yielded high-purity nanoparticles, whose morphological features were greatly affected by the reaction temperature.

In vitro hemocompatibility and cytocompatibility of dexamethasone-eluting PLGA stent coatings

NASA Astrophysics Data System (ADS)

Zhang, Jiang; Liu, Yang; Luo, Rifang; Chen, Si; Li, Xin; Yuan, Shuheng; Wang, Jin; Huang, Nan

2015-02-01

Drug-eluting stents (DESs) have been an important breakthrough for interventional cardiology applications since 2002. Though successful in reducing restenosis, some adverse clinical problems still emerged, which were mostly caused by the bare-metal stents and non-biodegradable polymer coatings, associated with the delayed endothelialization process. In this study, dexamethasone-loaded poly (lactic-co-glycolic acid) (PLGA) coatings were developed to explore the potential application of dexamethasone-eluting stents. Dexamethasone-eluting PLGA stents were prepared using ultrasonic atomization spray method. For other tests like stability and cytocompatibility and hemocompatibility tests, dexamethasone loaded coatings were deposited on 316L SS wafers. Fourier transform-infrared spectroscopy (FT-IR) results demonstrated that there was no chemical reaction between PLGA and dexamethasone. The balloon expansion experiment and surface morphology observation suggested that the stent coatings were smooth and uniform, and could also withstand the compressive and tensile strains imparted without cracking after stent expansion. The drug release behavior in vitro indicated that dexamethasone existed burst release within 1 day, but it presented linear release characteristics after 6 days. In vitro platelets adhesion, activation test and APTT test were also done, which showed that after blending dexamethasone into PLGA, the hemocompatibility was improved. Besides, dexamethasone and dexamethasone-loaded PLGA coatings could significantly inhibit the attachment and proliferation of smooth muscle cells.

Microwave-assisted green synthesis of superparamagnetic nanoparticles using fruit peel extracts: surface engineering, T 2 relaxometry, and photodynamic treatment potential.

PubMed

Bano, Shazia; Nazir, Samina; Nazir, Alia; Munir, Saeeda; Mahmood, Tariq; Afzal, Muhammad; Ansari, Farzana Latif; Mazhar, Kehkashan

2016-01-01

Superparamagnetic iron oxide nanoparticles (SPIONs) have the potential to be used as multimodal imaging and cancer therapy agents due to their excellent magnetism and ability to generate reactive oxygen species when exposed to light. We report the synthesis of highly biocompatible SPIONs through a facile green approach using fruit peel extracts as the biogenic reductant. This green synthesis protocol involves the stabilization of SPIONs through coordination of different phytochemicals. The SPIONs were functionalized with polyethylene glycol (PEG)-6000 and succinic acid and were extensively characterized by X-ray diffraction analysis, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, Rutherford backscattering spectrometry, diffused reflectance spectroscopy, fluorescence emission, Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, and magnetization analysis. The developed SPIONs were found to be stable, almost spherical with a size range of 17-25 nm. They exhibited excellent water dispersibility, colloidal stability, and relatively high R 2 relaxivity (225 mM(-1) s(-1)). Cell viability assay data revealed that PEGylation or carboxylation appears to significantly shield the surface of the particles but does not lead to improved cytocompatibility. A highly significant increase of reactive oxygen species in light-exposed samples was found to play an important role in the photokilling of human cervical epithelial malignant carcinoma (HeLa) cells. The bio-SPIONs developed are highly favorable for various biomedical applications without risking interference from potentially toxic reagents.

Microwave-assisted green synthesis of superparamagnetic nanoparticles using fruit peel extracts: surface engineering, T2 relaxometry, and photodynamic treatment potential

PubMed Central

Bano, Shazia; Nazir, Samina; Nazir, Alia; Munir, Saeeda; Mahmood, Tariq; Afzal, Muhammad; Ansari, Farzana Latif; Mazhar, Kehkashan

2016-01-01

Superparamagnetic iron oxide nanoparticles (SPIONs) have the potential to be used as multimodal imaging and cancer therapy agents due to their excellent magnetism and ability to generate reactive oxygen species when exposed to light. We report the synthesis of highly biocompatible SPIONs through a facile green approach using fruit peel extracts as the biogenic reductant. This green synthesis protocol involves the stabilization of SPIONs through coordination of different phytochemicals. The SPIONs were functionalized with polyethylene glycol (PEG)-6000 and succinic acid and were extensively characterized by X-ray diffraction analysis, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, Rutherford backscattering spectrometry, diffused reflectance spectroscopy, fluorescence emission, Fourier-transform infrared spectroscopy, ultraviolet-visible spectroscopy, and magnetization analysis. The developed SPIONs were found to be stable, almost spherical with a size range of 17–25 nm. They exhibited excellent water dispersibility, colloidal stability, and relatively high R2 relaxivity (225 mM−1 s−1). Cell viability assay data revealed that PEGylation or carboxylation appears to significantly shield the surface of the particles but does not lead to improved cytocompatibility. A highly significant increase of reactive oxygen species in light-exposed samples was found to play an important role in the photokilling of human cervical epithelial malignant carcinoma (HeLa) cells. The bio-SPIONs developed are highly favorable for various biomedical applications without risking interference from potentially toxic reagents. PMID:27570452

Cross-linkable graphene oxide embedded nanocomposite hydrogel with enhanced mechanics and cytocompatibility for tissue engineering.

PubMed

Liu, Xifeng; Miller, A Lee; Waletzki, Brian E; Lu, Lichun

2018-05-01

Graphene oxide (GO) is an attractive material that can be utilized to enhance the modulus and conductivities of substrates and hydrogels. To covalently cross-link graphene oxide sheets into hydrogels, abundant cross-linkable double bonds were introduced to synthesize the graphene-oxide-tris-acrylate sheet (GO-TrisA). Polyacrylamide (PAM) nanocomposite hydrogels were then fabricated with inherent covalently and permanently cross-linked GO-TrisA sheets. Results showed that the covalently cross-linked GO-TrisA/PAM nanocomposite hydrogel had enhanced mechanical strength, thermo stability compared with GO/PAM hydrogel maintained mainly by hydrogen bonding between PAM chains and GO sheets. In vitro cell study showed that the covalently cross-linked rGO-TrisA/PAM nanocomposite hydrogel had excellent cytocompatibility after in situ reduction. These results suggest that rGO-TrisA/PAM nanocomposite hydrogel holds great potential for tissue engineering applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1247-1257, 2018. © 2018 Wiley Periodicals, Inc.

Haemocompatibility of iron oxide nanoparticles synthesized for theranostic applications: a high-sensitivity microfluidic tool

NASA Astrophysics Data System (ADS)

Rodrigues, Raquel O.; Bañobre-López, Manuel; Gallo, Juan; Tavares, Pedro B.; Silva, Adrián M. T.; Lima, Rui; Gomes, Helder T.

2016-07-01

The poor heating efficiency of the most reported magnetic nanoparticles (MNPs), allied to the lack of comprehensive biocompatibility and haemodynamic studies, hampers the spread of multifunctional nanoparticles as the next generation of therapeutic bio-agents in medicine. The present work reports the synthesis and characterization, with special focus on biological/toxicological compatibility, of superparamagnetic nanoparticles with diameter around 18 nm, suitable for theranostic applications (i.e. simultaneous diagnosis and therapy of cancer). Envisioning more insights into the complex nanoparticle-red blood cells (RBCs) membrane interaction, the deformability of the human RBCs in contact with magnetic nanoparticles (MNPs) was assessed for the first time with a microfluidic extensional approach, and used as an indicator of haematological disorders in comparison with a conventional haematological test, i.e. the haemolysis analysis. Microfluidic results highlight the potential of this microfluidic tool over traditional haemolysis analysis, by detecting small increments in the rigidity of the blood cells, when traditional haemotoxicology analysis showed no significant alteration (haemolysis rates lower than 2 %). The detected rigidity has been predicted to be due to the wrapping of small MNPs by the bilayer membrane of the RBCs, which is directly related to MNPs size, shape and composition. The proposed microfluidic tool adds a new dimension into the field of nanomedicine, allowing to be applied as a high-sensitivity technique capable of bringing a better understanding of the biological impact of nanoparticles developed for clinical applications.

Supramolecule-Inspired Fabrication of Carbon Nanoparticles In Situ Anchored Graphene Nanosheets Material for High-Performance Supercapacitors.

PubMed

Huang, Yulan; Gao, Aimei; Song, Xiaona; Shu, Dong; Yi, Fenyun; Zhong, Jie; Zeng, Ronghua; Zhao, Shixu; Meng, Tao

2016-10-12

The remarkable electrochemical performance of graphene-based materials has drawn a tremendous amount of attention for their application in supercapacitors. Inspired by supramolecular chemistry, the supramolecular hydrogel is prepared by linking β-cyclodextrin to graphene oxide (GO). The carbon nanoparticles-anchored graphene nanosheets are then assembled after the hydrothermal reduction and carbonization of the supramolecular hydrogels; here, the β-cyclodextrin is carbonized to carbon nanoparticles that are uniformly anchored on the graphene nanosheets. Transmission electron microscopy reveals that carbon nanoparticles with several nanometers are uniformly anchored on both sides of graphene nanosheets, and X-ray diffraction spectra demonstrate that the interlayer spacing of graphene is enlarged due to the anchored nanoparticles among the graphene nanosheets. The as-prepared carbon nanoparticles-anchored graphene nanosheets material (C/r-GO-1:3) possesses a high specific capacitance (310.8 F g -1 , 0.5 A g -1 ), superior rate capability (242.5 F g -1 , 10 A g -1 ), and excellent cycle stability (almost 100% after 10 000 cycles, at the scan rate of 50 mV s -1 ). The outstanding electrochemical performance of the resulting C/r-GO-1:3 is mainly attributed to (i) the presence of the carbon nanoparticles, (ii) the enlarged interlayer spacing of the graphene sheets, and (iii) the accelerated ion transport rates toward the interior of the electrode material. The supramolecule-inspired approach for the synthesis of high-performance carbon nanoparticles-modified graphene sheets material is promising for future application in graphene-based energy storage devices.

Highly dispersible diamond nanoparticles for pretreatment of diamond films on Si substrate

NASA Astrophysics Data System (ADS)

Zhao, Shenjie; Huang, Jian; Zhou, Xinyu; Ren, Bing; Tang, Ke; Xi, Yifan; Wang, Lin; Wang, Linjun; Lu, Yicheng

2018-03-01

High quality diamond film on Si substrate was synthesized by coating diamond nanoparticles prepared by polyglycerol grafting (ND-PG) dispersion as pre-treatment method. Transmission electron microscope indicates that ND-PG is much more dispersible than untreated nanoparticles in organic solvents. The surface morphology was characterized by scanning electron microscope while atomic force microscope was conducted to measure the surface roughness. Microstructure properties were carried out by Raman spectroscopy and X-ray diffraction. The results revealed an increase in nucleation density, an acceleration of growth rate and an improvement of film crystalline quality by using spin-coating ND-PG pretreatment.

Cr2O3 nanoparticles: Advanced electrode materials for high performance pseudocapacitors

NASA Astrophysics Data System (ADS)

Babu, I. Manohara; William, J. Johnson; Muralidharan, G.

2017-05-01

Cr2O3 nanoparticles have been synthesized via simple and facile microwave irradiation method. The structural, morphological and electrochemical performances of Cr2O3 nanoparticles have been studied. Electrochemical analysis indicates the Cr2O3 electrodes to be good pseudocapacitor material with a specific capacitance (122 F g-1 at a constant current of 1 A g-1), high energy density (6.08 W h kg-1), large power density (218.98 W kg-1). These results allow us to state with confidence that new class of electrode materials with good electrochemical performance has been identified.

High stable suspension of magnetite nanoparticles in ethanol by using sono-synthesized nanomagnetite in polyol medium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bastami, Tahereh Rohani; Entezari, Mohammad H., E-mail: moh_entezari@yahoo.com

2013-09-01

Graphical abstract: - Highlights: • The sonochemical synthesis of magnetite nanoparticles was carried out in EG without any surfactant. • The nanoparticles with sizes ∼24 nm were composed of small building blocks with sizes ∼2 nm. • The hydrophilic magnetite nanoparticles were stable in ethanol even after 8 months. • Ultrasonic intensity showed a crucial role on the obtained high stable magnetite nanoparticles in ethanol. - Abstract: The sonochemical synthesis of magnetite nanoparticles was carried out at relatively low temperature (80 °C) in ethylene glycol (EG) as a polyol solvent. The particle size was determined by transmission electron microscopy (TEM).more » The magnetite nanoparticles with an average size of 24 nm were composed of small building blocks with an average size of 2–3 nm and the particles exhibited nearly spherical shape. The surface characterization was investigated by using Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The stability of magnetite nanoparticles was studied in ethanol as a polar solvent. The nanoparticles showed an enhanced stability in ethanol which is due to the hydrophilic surface of the particles. The colloidal stability of magnetite nanoparticles in ethanol was monitored by UV–visible spectrophotometer. According to the results, the nanoparticles synthesized in 30 min of sonication with intensity of 35 W/cm{sup 2} (50%) led to a maximum stability in ethanol as a polar solvent with respect to the other applied intensities. The obtained magnetite nanoparticles were stable for more than12 months.« less

Cast Aluminum Alloys for High Temperature Applications Using Nanoparticles Al2O3 and Al3-X Compounds (X = Ti, V, Zr)

NASA Technical Reports Server (NTRS)

Lee, Jonathan A.

2009-01-01

In this paper, the effect of nanoparticles Al2O3 and Al3-X compounds (X = Ti, V, Zr) on the improvement of mechanical properties of aluminum alloys for elevated temperature applications is presented. These nanoparticles were selected based on their low cost, chemical stability and low diffusions rates in aluminum at high temperatures. The strengthening mechanism at high temperature for aluminum alloy is based on the mechanical blocking of dislocation movements by these nanoparticles. For Al2O3 nanoparticles, the test samples were prepared from special Al2O3 preforms, which were produced using ceramic injection molding process and then pressure infiltrated by molten aluminum. In another method, Al2O3 nanoparticles can also be homogeneously mixed with fine aluminum powder and consolidated into test samples through hot pressing and sintering. With the Al3-X nanoparticles, the test samples are produced as precipitates from in-situ reactions with molten aluminum using conventional permanent mold or die casting techniques. It is found that cast aluminum alloy using nanoparticles Al3-X is the most cost effective method to produce high strength aluminum alloys for high temperature applications in comparison to nanoparticles Al2O3. Furthermore, significant mechanical properties retention in high temperature environment could be achieved with Al3-X nanoparticles, resulting in tensile strength of nearly 3 times higher than most 300- series conventional cast aluminum alloys tested at 600 F.

Functional Magnetic Nanoparticles for Highly Efficient Cholesterol Removal.

PubMed

Sun, Jun; Xu, Bin; Mu, Yaoyao; Ma, Haile; Qu, Wenjuan

2018-01-01

In this study, magnetic nanoparticles functionalized with carboxylated β-cyclodextrin (CM-β-CD; referred to Fe 3 O 4 @CM-β-CD) were synthesized and used for the efficient removal of cholesterol from milk and egg yolk via host-guest interactions. The results of Fourier-transform infrared, X-ray photoelectron spectroscopy, and thermogravimetric analysis indicated that the CM-β-CD was successfully conjugated to the surface of Fe 3 O 4 , and the amount of CM-β-CD attached on Fe 3 O 4 @CM-β-CD was determined to be 9.164%. The X-ray diffraction and transmission electron microscopy data revealed that the process of CM-β-CD coating did not result in a phase change of the Fe 3 O 4 , and the Fe 3 O 4 @CM-β-CD nanoparticles were determined to have an average size of about 15 nm. The results of isotherm adsorption and kinetic properties indicated that CM-β-CD functionalization increased the cholesterol removal efficiency, and the characteristics of cholesterol adsorption on Fe 3 O 4 @CM-β-CD were fitted well with the Langmuir adsorption model and Lagergren pseudo-1st-order kinetic models. Furthermore, compared with the Fe 3 O 4 nanoparticles, the functionalized Fe 3 O 4 @CM-β-CD nanoparticles exhibited greater cholesterol removal efficiency, and saponification of the milk and egg yolk was found to be beneficial for the cholesterol removal; using the Fe 3 O 4 @CM-β-CD nanoparticles, 98.8% and 94.6% of the cholesterol was extracted in 1 h from saponified milk and egg yolk, respectively, and the Fe 3 O 4 @CM-β-CD nanoparticles still displayed efficient cholesterol removal after 6 reuses. © 2017 Institute of Food Technologists®.

A hypothetical model for predicting the toxicity of high aspect ratio nanoparticles (HARN)

NASA Astrophysics Data System (ADS)

Tran, C. L.; Tantra, R.; Donaldson, K.; Stone, V.; Hankin, S. M.; Ross, B.; Aitken, R. J.; Jones, A. D.

2011-12-01

The ability to predict nanoparticle (dimensional structures which are less than 100 nm in size) toxicity through the use of a suitable model is an important goal if nanoparticles are to be regulated in terms of exposures and toxicological effects. Recently, a model to predict toxicity of nanoparticles with high aspect ratio has been put forward by a consortium of scientists. The High aspect ratio nanoparticles (HARN) model is a platform that relates the physical dimensions of HARN (specifically length and diameter ratio) and biopersistence to their toxicity in biological environments. Potentially, this model is of great public health and economic importance, as it can be used as a tool to not only predict toxicological activity but can be used to classify the toxicity of various fibrous nanoparticles, without the need to carry out time-consuming and expensive toxicology studies. However, this model of toxicity is currently hypothetical in nature and is based solely on drawing similarities in its dimensional geometry with that of asbestos and synthetic vitreous fibres. The aim of this review is two-fold: (a) to present findings from past literature, on the physicochemical property and pathogenicity bioassay testing of HARN (b) to identify some of the challenges and future research steps crucial before the HARN model can be accepted as a predictive model. By presenting what has been done, we are able to identify scientific challenges and research directions that are needed for the HARN model to gain public acceptance. Our recommendations for future research includes the need to: (a) accurately link physicochemical data with corresponding pathogenicity assay data, through the use of suitable reference standards and standardised protocols, (b) develop better tools/techniques for physicochemical characterisation, (c) to develop better ways of monitoring HARN in the workplace, (d) to reliably measure dose exposure levels, in order to support future epidemiological

Rare Earth Oxide Fluoride Nanoparticles And Hydrothermal Method For Forming Nanoparticles

DOEpatents

Fulton, John L.; Hoffmann, Markus M.

2003-12-23

A hydrothermal method for forming nanoparticles of a rare earth element, oxygen and fluorine has been discovered. Nanoparticles comprising a rare earth element, oxygen and fluorine are also described. These nanoparticles can exhibit excellent refractory properties as well as remarkable stability in hydrothermal conditions. The nanoparticles can exhibit excellent properties for numerous applications including fiber reinforcement of ceramic composites, catalyst supports, and corrosion resistant coatings for high-temperature aqueous solutions.

Rare earth oxide fluoride nanoparticles and hydrothermal method for forming nanoparticles

DOEpatents

Fulton, John L [Richland, WA; Hoffmann, Markus M [Richland, WA

2001-11-13

A hydrothermal method for forming nanoparticles of a rare earth element, oxygen and fluorine has been discovered. Nanoparticles comprising a rare earth element, oxygen and fluorine are also described. These nanoparticles can exhibit excellent refractory properties as well as remarkable stability in hydrothermal conditions. The nanoparticles can exhibit excellent properties for numerous applications including fiber reinforcement of ceramic composites, catalyst supports, and corrosion resistant coatings for high-temperature aqueous solutions.

Potential for enhancing external beam radiotherapy for lung cancer using high-Z nanoparticles administered via inhalation

NASA Astrophysics Data System (ADS)

Hao, Yao; Altundal, Yucel; Moreau, Michele; Sajo, Erno; Kumar, Rajiv; Ngwa, Wilfred

2015-09-01

Nanoparticle-aided radiation therapy is emerging as a promising modality to enhance radiotherapy via the radiosensitizing action of high atomic number (Z) nanoparticles. However, the delivery of sufficiently potent concentrations of such nanoparticles to the tumor remain a challenge. This study investigates the dose enhancement to lung tumors due to high-Z nanoparticles (NPs) administered via inhalation during external beam radiotherapy. Here NPs investigated include: cisplatin nanoparticles (CNPs), carboplatin nanoparticles (CBNPs), and gold nanoparticles (GNPs). Using Monte Carlo-generated megavoltage energy spectra, a previously employed analytic method was used to estimate dose enhancement to lung tumors due to radiation-induced photoelectrons from the NPs administered via inhalation route (IR) in comparison to intravenous (IV) administration. Previous studies have indicated about 5% of FDA-approved cisplatin concentrations reach the lung via IV. Meanwhile recent experimental studies indicate that 3.5-14.6 times higher concentrations of NPs can reach the lung by IR compared to IV. Taking these into account, the dose enhancement factor (DEF) defined as the ratio of the radiotherapy dose with and without nanoparticles was calculated for a range of NPs concentrations and tumor sizes. The DEF for IR was then compared with that for IV. For IR with 3.5 times higher concentrations than IV, and 2 cm diameter tumor, clinically significant DEF values of up to 1.19, 1.26, and 1.51 were obtained for CNPs, CBNPs and GNPs. In comparison values of 1.06, 1.08, and 1.15 were obtained via IV administration. For IR with 14.6 times higher concentrations, even higher DEF values were obtained e.g. 1.81 for CNPs. Results also showed that the DEF increased with increasing field size or decreasing tumor volume, as expected. The results of this work indicate that IR administration of targeted high-Z CNPs/CBNPs/GNPs could enable clinically significant DEF to lung tumors compared to IV

Enhanced Raman scattering of single nanoparticles in a high-Q whispering-gallery microresonator

NASA Astrophysics Data System (ADS)

Liu, Rui-Shan; Jin, Wei-Liang; Yu, Xiao-Chong; Liu, Yong-Chun; Xiao, Yun-Feng

2015-04-01

We study Raman scattering of single nanoparticles coupled to a high-Q whispering-gallery microresonator. It is found that cavity resonances greatly enhance the Raman signal, and the enhancement factor is as high as 108. Unlike the noncavity case, the signal power exhibits a nonmonotonic dependence on particle size, and it reaches the maximum when the Rayleigh scattering loss and the cavity intrinsic loss are comparable. We further analyze how the Raman signal intensity is influenced by different parameters including cavity quality factors and taper-cavity coupling strength. The detection limit of observing single-nanoparticle Raman signal is discussed finally. As a potential application, this mechanism may provide an alternative way to detect specific biological targets without the need of precovered biorecognitions.

Nanocarbon synthesis by high-temperature oxidation of nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nomura, Ken-ichi; Kalia, Rajiv K.; Li, Ying

High-temperature oxidation of silicon-carbide nanoparticles (nSiC) underlies a wide range of technologies from high-power electronic switches for efficient electrical grid and thermal protection of space vehicles to self-healing ceramic nanocomposites. Here, multimillion-atom reactive molecular dynamics simulations validated by ab initio quantum molecular dynamics simulations predict unexpected condensation of large graphene flakes during high-temperature oxidation of nSiC. Initial oxidation produces a molten silica shell that acts as an autocatalytic ‘nanoreactor’ by actively transporting oxygen reactants while protecting the nanocarbon product from harsh oxidizing environment. Percolation transition produces porous nanocarbon with fractal geometry, which consists of mostly sp 2 carbons with pentagonalmore » and heptagonal defects. Furthermore, this work suggests a simple synthetic pathway to high surface-area, low-density nanocarbon with numerous energy, biomedical and mechanical-metamaterial applications, including the reinforcement of self-healing composites.« less

Nanocarbon synthesis by high-temperature oxidation of nanoparticles

DOE PAGES

Nomura, Ken-ichi; Kalia, Rajiv K.; Li, Ying; ...

2016-04-20

High-temperature oxidation of silicon-carbide nanoparticles (nSiC) underlies a wide range of technologies from high-power electronic switches for efficient electrical grid and thermal protection of space vehicles to self-healing ceramic nanocomposites. Here, multimillion-atom reactive molecular dynamics simulations validated by ab initio quantum molecular dynamics simulations predict unexpected condensation of large graphene flakes during high-temperature oxidation of nSiC. Initial oxidation produces a molten silica shell that acts as an autocatalytic ‘nanoreactor’ by actively transporting oxygen reactants while protecting the nanocarbon product from harsh oxidizing environment. Percolation transition produces porous nanocarbon with fractal geometry, which consists of mostly sp 2 carbons with pentagonalmore » and heptagonal defects. Furthermore, this work suggests a simple synthetic pathway to high surface-area, low-density nanocarbon with numerous energy, biomedical and mechanical-metamaterial applications, including the reinforcement of self-healing composites.« less

Nanocarbon synthesis by high-temperature oxidation of nanoparticles

PubMed Central

Nomura, Ken-ichi; Kalia, Rajiv K.; Li, Ying; Nakano, Aiichiro; Rajak, Pankaj; Sheng, Chunyang; Shimamura, Kohei; Shimojo, Fuyuki; Vashishta, Priya

2016-01-01

High-temperature oxidation of silicon-carbide nanoparticles (nSiC) underlies a wide range of technologies from high-power electronic switches for efficient electrical grid and thermal protection of space vehicles to self-healing ceramic nanocomposites. Here, multimillion-atom reactive molecular dynamics simulations validated by ab initio quantum molecular dynamics simulations predict unexpected condensation of large graphene flakes during high-temperature oxidation of nSiC. Initial oxidation produces a molten silica shell that acts as an autocatalytic ‘nanoreactor’ by actively transporting oxygen reactants while protecting the nanocarbon product from harsh oxidizing environment. Percolation transition produces porous nanocarbon with fractal geometry, which consists of mostly sp2 carbons with pentagonal and heptagonal defects. This work suggests a simple synthetic pathway to high surface-area, low-density nanocarbon with numerous energy, biomedical and mechanical-metamaterial applications, including the reinforcement of self-healing composites. PMID:27095061

Highly bacterial resistant silver nanoparticles: synthesis and antibacterial activities

NASA Astrophysics Data System (ADS)

Chudasama, Bhupendra; Vala, Anjana K.; Andhariya, Nidhi; Mehta, R. V.; Upadhyay, R. V.

2010-06-01

In this article, we describe a simple one-pot rapid synthesis route to produce uniform silver nanoparticles by thermal reduction of AgNO3 using oleylamine as reducing and capping agent. To enhance the dispersal ability of as-synthesized hydrophobic silver nanoparticles in water, while maintaining their unique properties, a facile phase transfer mechanism has been developed using biocompatible block co-polymer pluronic F-127. Formation of silver nanoparticles is confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-vis spectroscopy. Hydrodynamic size and its distribution are obtained from dynamic light scattering (DLS). Hydrodynamic size and size distribution of as-synthesized and phase transferred silver nanoparticles are 8.2 ± 1.5 nm (σ = 18.3%) and 31.1 ± 4.5 nm (σ = 14.5%), respectively. Antimicrobial activities of hydrophilic silver nanoparticles is tested against two Gram positive ( Bacillus megaterium and Staphylococcus aureus), and three Gram negative ( Escherichia coli, Proteus vulgaris and Shigella sonnei) bacteria. Minimum inhibitory concentration (MIC) values obtained in the present study for the tested microorganisms are found much better than those reported for commercially available antibacterial agents.

Polymeric nanoparticles for increased oral bioavailability and rapid absorption using celecoxib as a model of a low-solubility, high-permeability drug.

PubMed

Morgen, Michael; Bloom, Corey; Beyerinck, Ron; Bello, Akintunde; Song, Wei; Wilkinson, Karen; Steenwyk, Rick; Shamblin, Sheri

2012-02-01

To demonstrate drug/polymer nanoparticles can increase the rate and extent of oral absorption of a low-solubility, high-permeability drug. Amorphous drug/polymer nanoparticles containing celecoxib were prepared using ethyl cellulose and either sodium caseinate or bile salt. Nanoparticles were characterized using dynamic light scattering, transmission and scanning electron microscopy, and differential scanning calorimetry. Drug release and resuspension studies were performed using high-performance liquid chromatography. Pharmacokinetic studies were performed in dogs and humans. A physical model is presented describing the nanoparticle state of matter and release performance. Nanoparticles dosed orally in aqueous suspensions provided higher systemic exposure and faster attainment of peak plasma concentrations than commercial capsules, with median time to maximum drug concentration (Tmax) of 0.75 h in humans for nanoparticles vs. 3 h for commercial capsules. Nanoparticles released celecoxib rapidly and provided higher dissolved-drug concentrations than micronized crystalline drug. Nanoparticle suspensions are stable for several days and can be spray-dried to form dry powders that resuspend in water. Drug/polymer nanoparticles are well suited for providing rapid oral absorption and increased bioavailability of BCS Class II drugs.

Photodeposition of Gold, Platinum, or Silver onto Titanium Dioxide Nanoparticles at Steps of Highly Oriented Pyrolytic Graphite

NASA Astrophysics Data System (ADS)

Taing, James

The photodeposition of gold, platinum, or silver nanoparticles selectively onto isolated titanium dioxide (TiO2) nanoparticles created metal/TiO2 photocatalysts and heterogeneous catalysts, and validated the photocatalytic property of the semiconductor. The isolated and ordered TiO2 nanoparticles permitted clear observations of the stability, and changes in morphology, of the particles in various experimental conditions. The fabrication of TiO2 nanoparticles at the steps of highly oriented pyrolytic graphite (HOPG), utilizing physical vapor deposition, required heating the graphite substrate to a minimum of 800 °C. The production of a photocurrent, and plating of gold nanoparticles, confirmed the photocatalytic property of the TiO2 nanoparticles on HOPG when utilized as a photoelectrode in a two half-cell setup. Employing sodium chloride (1.0 M) as an electrolyte resulted in an increase/decrease of the photocurrent with the addition of gold cations to the half-cell without/with the TiO2 nanoparticles. A poor distribution of gold nanoparticles, roughly 40-45 nm wide, deposited around few of the TiO2 nanoparticles. A lower concentration of sodium chloride (0.1 M) resulted in a coalescence of Au nanoparticles, roughly 10 nm, around many TiO2 nanoparticles. Using sodium nitrate as an electrolyte resulted in a rapid decay in the photocurrent and a growth of an unidentified material on the TiO2 nanoparticles. The unidentified material hindered the reduction of gold cations introduced midway through the experiment. With gold cations present at the onset of the experiment, disperse gold nanoparticles (˜5-10 nm) deposited around the TiO2 nanoparticles. In the absence of additional electrolyte, many disperse gold nanoparticles less than 5 nm deposited onto the TiO2 nanoparticles. More platinum than gold selectively deposited onto the TiO2 nanoparticles. On the contrary, less silver selectively deposited onto the TiO2 nanoparticles. Scanning electron microscopy and atomic

A highly sensitive magnetic biosensor for detection and quantification of anticancer drugs tagged to superparamagnetic nanoparticles

NASA Astrophysics Data System (ADS)

Wingo, J.; Devkota, J.; Mai, T. T. T.; Nguyen, X. P.; Mukherjee, P.; Srikanth, H.; Phan, M. H.; Vietnam Academy of Science and Technology Collaboration; University of South Florida Team

2014-03-01

A precise detection of low concentrations of biomolecules attached to magnetic nanoparticles in complex biological systems is a challenging task and requires biosensors with improved sensitivity. Here, we present a highly sensitive magnetic biosensor based on the magneto-reactance (MX) effect of a Co65Fe4Ni2Si15B14 amorphous ribbon with nanohole-patterned surface for detection and quantification of anticancer drugs (Curcumin) tagged to Fe3O4 nanoparticles. The detection and quantification of Curcumin were assessed by the change in MX of the ribbon subject to varying concentrations of the functionalized Fe3O4 nanoparticles. A high capacity of the MX-based biosensor in quantitative analysis of the nanoparticles was achieved in the range of 0 - 50 ng/ml, beyond which the detection sensitivity (η) remained unchanged. The η of the biosensor reached an extremely high value of 30%, which is about 4-5 times higher than that of a magneto-impedance (MI) based biosensor. This biosensor is well suited for detection of low-concentration magnetic biomarkers in biological systems. This work was supported by was supported by the Florida Cluster for Advanced Smart Sensor Technologies, USAMRMC (Grant # W81XWH-07-1-0708), and the NSF-funded REU program at the USF.

Highly coke-resistant ni nanoparticle catalysts with minimal sintering in dry reforming of methane.

PubMed

Han, Joung Woo; Kim, Chanyeon; Park, Jun Seong; Lee, Hyunjoo

2014-02-01

Nickel catalysts are typically used for hydrogen production by reforming reactions. Reforming methane with carbon dioxide, called dry reforming of methane (DRM), is a good way to produce hydrogen or syngas (a mixture of hydrogen and carbon monoxide) from two notable greenhouse gases. However, Ni catalysts used for DRM suffer from severe coke deposition. It has been known that small Ni nanoparticles are advantageous to reduce coke formation, but the high reaction temperature of DRM (800 °C) inevitably induces aggregation of the nanoparticles, leading to severe coke formation and degraded activity. Here, we develop highly coke-resistant Ni catalysts by immobilizing premade Ni nanoparticles of 5.2 nm in size onto functionalized silica supports, and then coating the Ni/SiO2 catalyst with silica overlayers. The silica overlayers enable the transfer of reactants and products while preventing aggregation of the Ni nanoparticles. The silica-coated Ni catalysts operate stably for 170 h without any degradation in activity. No carbon deposition was observed by temperature programmed oxidation (TPO), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy. The Ni catalysts without silica coating show severe sintering after DRM reaction, and the formation of filamentous carbon was observed. The coke-resistant Ni catalyst is potentially useful in various hydrocarbon transformations. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Laser-induced incandescence (LII) diagnostic for in situ monitoring of nanoparticle synthesis in a high-pressure arc discharge

NASA Astrophysics Data System (ADS)

Yatom, Shurik; Vekselman, Vladislav; Mitrani, James; Stratton, Brentley; Raitses, Yevgeny; LaboratoryPlasma Nanosynthesis Team

2016-10-01

A DC arc discharge is commonly used for synthesis of carbon nanoparticles, including buckyballs, carbon nanotubes, and graphene flakes. In this work we show the first results of nanoparticles monitored during the arc discharge. The graphite electrode is vaporized by high current (60 A) in a buffer Helium gas leading to nanoparticle synthesis in a low temperature plasma. The arc was shown to oscillate, which can possibly influence the nano-synthesis. To visualize the nanoparticles in-situ we employ the LII technique. The nanoparticles with radii >50 nm, emerging from the arc area are heated with a short laser pulse and incandesce. The resulting radiation is captured with an ICCD camera, showing the location of the generated nanoparticles. The images of incandescence are studied together with temporally synchronized fast-framing imaging of C2 emission, to connect the dynamics of arc instabilities, C2 molecules concentration and nanoparticles. The time-resolved incandescence signal is analyzed with combination of ex-situ measurements of the synthesized nanoparticles and LII modeling, to provide the size distribution of produced nanoparticles. This work was supported by US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division.

Preparation, characterization, and antibacterial activity of silver nanoparticle-decorated graphene oxide nanocomposite.

PubMed

Shao, Wei; Liu, Xiufeng; Min, Huihua; Dong, Guanghui; Feng, Qingyuan; Zuo, Songlin

2015-04-01

In this work, we report a facile and green approach to prepare a uniform silver nanoparticles (AgNPs) decorated graphene oxide (GO) nanocomposite (GO-Ag). The nanocomposite was fully characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectra, ultraviolet-visible (UV-vis) absorption spectra, and X-ray photoelectron spectroscopy (XPS), which demonstrated that AgNPs with a diameter of approximately 22 nm were uniformly and compactly deposited on GO. To investigate the silver ion release behaviors, HEPES buffers with different pH (5.5, 7, and 8.5) were selected and the mechanism of release actions was discussed in detail. The cytotoxicity of GO-Ag nanocomposite was also studied using HEK 293 cells. GO-Ag nanocomposite displayed good cytocompatibility. Furthermore, the antibacterial properties of GO-Ag nanocomposite were studied using Gram-negative E. coli ATCC 25922 and Gram-positive S. aureus ATCC 6538 by both the plate count method and disk diffusion method. The nanocomposite showed excellent antibacterial activity. These results demonstrated that GO-Ag nanocomposite, as a kind of antibacterial material, had a great promise for application in a wide range of biomedical applications.

High-temperature-stable and regenerable catalysts: platinum nanoparticles in aligned mesoporous silica wells.

PubMed

Xiao, Chaoxian; Maligal-Ganesh, Raghu V; Li, Tao; Qi, Zhiyuan; Guo, Zhiyong; Brashler, Kyle T; Goes, Shannon; Li, Xinle; Goh, Tian Wei; Winans, Randall E; Huang, Wenyu

2013-10-01

We report the synthesis, structural characterization, thermal stability study, and regeneration of nanostructured catalysts made of 2.9 nm Pt nanoparticles sandwiched between a 180 nm SiO2 core and a mesoporous SiO2 shell. The SiO2 shell consists of 2.5 nm channels that are aligned perpendicular to the surface of the SiO2 core. The nanostructure mimics Pt nanoparticles that sit in mesoporous SiO2 wells (Pt@MSWs). By using synchrotron-based small-angle X-ray scattering, we were able to prove the ordered structure of the aligned mesoporous shell. By using high-temperature cyclohexane dehydrogenation as a model reaction, we found that the Pt@MSWs of different well depths showed stable activity at 500 °C after the induction period. Conversely, a control catalyst, SiO2 -sphere-supported Pt nanoparticles without a mesoporous SiO2 shell (Pt/SiO2 ), was deactivated. We deliberately deactivated the Pt@MSWs catalyst with a 50 nm deep well by using carbon deposition induced by a low H2 /cyclohexane ratio. The deactivated Pt@MSWs catalyst was regenerated by calcination at 500 °C with 20 % O2 balanced with He. After the regeneration treatments, the activity of the Pt@MSWs catalyst was fully restored. Our results suggest that the nanostructured catalysts-Pt nanoparticles confined inside mesoporous SiO2 wells-are stable and regenerable for treatments and reactions that require high temperatures. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of a bio-based hydrophobic cellulose laurate film as biomaterial--study on biodegradation and cytocompatibility.

PubMed

Crépy, Lucie; Monchau, Francine; Chai, Feng; Raoul, Gwénaël; Hivart, Philippe; Hildebrand, Hartmut F; Martin, Patrick; Joly, Nicolas

2012-05-01

The study aims to validate an original bio-based material, obtained by grafting fatty chains, and more especially lauric chains (C12) onto cellulose, for medical applications. The mechanical properties of the synthesized cellulose laurate (C12) are close to those of petrochemical ones such as low density polyethylene. This cellulose-based polymer is transparent, flexible, and hydrophobic. To evaluate the stability of the cellulosic films in biological fluids the samples are soaked in simulated body fluid or blood plasma for a few hours to 6 months, and then submitted to mechanical and chemical analyses. The simultaneously performed cytocompatibility tests were the colony-forming viability, the vitality and cell proliferation tests using NIH 3T3 fibroblasts and MC 3T3 osteoblast-like cells. The results show the stability, the biocompatibility, and the noncytotoxicity of the synthesized cellulose laurate films. This biomaterial may so be considered for surgical applications. Copyright © 2012 Wiley Periodicals, Inc.

Highly luminescent material based on Alq3:Ag nanoparticles.

PubMed

Salah, Numan; Habib, Sami S; Khan, Zishan H

2013-09-01

Tris (8-hydroxyquinoline) aluminum (Alq3) is an organic semiconductor molecule, widely used as an electron transport layer, light emitting layer in organic light-emitting diodes and a host for fluorescent and phosphorescent dyes. In this work thin films of pure and silver (Ag), cupper (Cu), terbium (Tb) doped Alq3 nanoparticles were synthesized using the physical vapor condensation method. They were fabricated on glass substrates and characterized by X-ray diffraction, scanning electron microscope (SEM), energy dispersive spectroscopy, atomic force microscope (AFM), UV-visible absorption spectra and studied for their photoluminescence (PL) properties. SEM and AFM results show spherical nanoparticles with size around 70-80 nm. These nanoparticles have almost equal sizes and a homogeneous size distribution. The maximum absorption of Alq3 nanoparticles is observed at 300 nm, while the surface plasmon resonant band of Ag doped sample appears at 450 nm. The PL emission spectra of Tb, Cu and Ag doped Alq3 nanoparticles show a single broad band at around 515 nm, which is similar to that of the pure one, but with enhanced PL intensity. The sample doped with Ag at a concentration ratio of Alq3:Ag = 1:0.8 is found to have the highest PL intensity, which is around 2 times stronger than that of the pure one. This enhancement could be attributed to the surface plasmon resonance of Ag ions that might have increased the absorption and then the quantum yield. These remarkable result suggest that Alq3 nanoparticles incorporated with Ag ions might be quite useful for future nano-optoelectronic devices.

Silver Nanoparticle-Deposited Boron Nitride Nanosheets as Fillers for Polymeric Composites with High Thermal Conductivity.

PubMed

Wang, Fangfang; Zeng, Xiaoliang; Yao, Yimin; Sun, Rong; Xu, Jianbin; Wong, Ching-Ping

2016-01-19

Polymer composites with high thermal conductivity have recently attracted much attention, along with the rapid development of the electronic devices toward higher speed and performance. However, a common method to enhance polymer thermal conductivity through an addition of high thermally conductive fillers usually cannot provide an expected value, especially for composites requiring electrical insulation. Here, we show that polymeric composites with silver nanoparticle-deposited boron nitride nanosheets as fillers could effectively enhance the thermal conductivity of polymer, thanks to the bridging connections of silver nanoparticles among boron nitride nanosheets. The thermal conductivity of the composite is significantly increased from 1.63 W/m-K for the composite filled with the silver nanoparticle-deposited boron nitride nanosheets to 3.06 W/m-K at the boron nitride nanosheets loading of 25.1 vol %. In addition, the electrically insulating properties of the composite are well preserved. Fitting the measured thermal conductivity of epoxy composite with one physical model indicates that the composite with silver nanoparticle-deposited boron nitride nanosheets outperforms the one with boron nitride nanosheets, owning to the lower thermal contact resistance among boron nitride nanosheets' interfaces. The finding sheds new light on enhancement of thermal conductivity of the polymeric composites which concurrently require the electrical insulation.

Silver Nanoparticle-Deposited Boron Nitride Nanosheets as Fillers for Polymeric Composites with High Thermal Conductivity

PubMed Central

Wang, Fangfang; Zeng, Xiaoliang; Yao, Yimin; Sun, Rong; Xu, Jianbin; Wong, Ching-Ping

2016-01-01

Polymer composites with high thermal conductivity have recently attracted much attention, along with the rapid development of the electronic devices toward higher speed and performance. However, a common method to enhance polymer thermal conductivity through an addition of high thermally conductive fillers usually cannot provide an expected value, especially for composites requiring electrical insulation. Here, we show that polymeric composites with silver nanoparticle-deposited boron nitride nanosheets as fillers could effectively enhance the thermal conductivity of polymer, thanks to the bridging connections of silver nanoparticles among boron nitride nanosheets. The thermal conductivity of the composite is significantly increased from 1.63 W/m-K for the composite filled with the silver nanoparticle-deposited boron nitride nanosheets to 3.06 W/m-K at the boron nitride nanosheets loading of 25.1 vol %. In addition, the electrically insulating properties of the composite are well preserved. Fitting the measured thermal conductivity of epoxy composite with one physical model indicates that the composite with silver nanoparticle-deposited boron nitride nanosheets outperforms the one with boron nitride nanosheets, owning to the lower thermal contact resistance among boron nitride nanosheets’ interfaces. The finding sheds new light on enhancement of thermal conductivity of the polymeric composites which concurrently require the electrical insulation. PMID:26783258

Increased brain uptake of targeted nanoparticles by adding an acid-cleavable linkage between transferrin and the nanoparticle core.

PubMed

Clark, Andrew J; Davis, Mark E

2015-10-06

Most therapeutic agents are excluded from entering the central nervous system by the blood-brain barrier (BBB). Receptor mediated transcytosis (RMT) is a common mechanism used by proteins, including transferrin (Tf), to traverse the BBB. Here, we prepared Tf-containing, 80-nm gold nanoparticles with an acid-cleavable linkage between the Tf and the nanoparticle core to facilitate nanoparticle RMT across the BBB. These nanoparticles are designed to bind to Tf receptors (TfRs) with high avidity on the blood side of the BBB, but separate from their multidentate Tf-TfR interactions upon acidification during the transcytosis process to allow release of the nanoparticle into the brain. These targeted nanoparticles show increased ability to cross an in vitro model of the BBB and, most important, enter the brain parenchyma of mice in greater amounts in vivo after systemic administration compared with similar high-avidity nanoparticles containing noncleavable Tf. In addition, we investigated this design with nanoparticles containing high-affinity antibodies (Abs) to TfR. With the Abs, the addition of the acid-cleavable linkage provided no improvement to in vivo brain uptake for Ab-containing nanoparticles, and overall brain uptake was decreased for all Ab-containing nanoparticles compared with Tf-containing ones. These results are consistent with recent reports of high-affinity anti-TfR Abs trafficking to the lysosome within BBB endothelium. In contrast, high-avidity, Tf-containing nanoparticles with the acid-cleavable linkage avoid major endothelium retention by shedding surface Tf during their transcytosis.

Comparison of charged nanoparticle concentrations near busy roads and overhead high-voltage power lines.

PubMed

Jayaratne, E R; Ling, X; Morawska, L

2015-09-01

Overhead high-voltage power lines are known sources of corona ions. These ions rapidly attach to aerosols to form charged particles in the environment. Although the effect of ions and charged particles on human health is largely unknown, much attention has focused on the increasing exposure as a result of the expanding power network in urban residential areas. However, it is not widely known that a large number of charged particles in urban environments originate from motor vehicle emissions. In this study, for the first time, we compare the concentrations of charged nanoparticles near busy roads and overhead power lines. We show that large concentrations of both positive and negative charged nanoparticles are present near busy roadways and that these concentrations commonly exceed those under high-voltage power lines. We estimate that the concentration of charged nanoparticles found near two freeways carrying around 120 vehicles per minute exceeded the corresponding maximum concentrations under two corona-emitting overhead power lines by as much as a factor of 5. The difference was most pronounced when a significant fraction of traffic consisted of heavy-duty diesel vehicles which typically have high particle and charge emission rates. Copyright © 2015 Elsevier B.V. All rights reserved.

High frequency lateral flow affinity assay using superparamagnetic nanoparticles

NASA Astrophysics Data System (ADS)

Lago-Cachón, D.; Rivas, M.; Martínez-García, J. C.; Oliveira-Rodríguez, M.; Blanco-López, M. C.; García, J. A.

2017-02-01

Lateral flow assay is one of the simplest and most extended techniques in medical diagnosis for point-of-care testing. Although it has been traditionally a positive/negative test, some work has been lately done to add quantitative abilities to lateral flow assay. One of the most successful strategies involves magnetic beads and magnetic sensors. Recently, a new technique of superparamagnetic nanoparticle detection has been reported, based on the increase of the impedance induced by the nanoparticles on a RF-current carrying copper conductor. This method requires no external magnetic field, which reduces the system complexity. In this work, nitrocellulose membranes have been installed on the sensor, and impedance measurements have been carried out during the sample diffusion by capillarity along the membrane. The impedance of the sensor changes because of the presence of magnetic nanoparticles. The results prove the potentiality of the method for point-of-care testing of biochemical substances and nanoparticle capillarity flow studies.

Fabrication of thermoplastic ductile films of chitin butyrate/poly(ɛ-caprolactone) blends and their cytocompatibility.

PubMed

Hashiwaki, Hiroki; Teramoto, Yoshikuni; Nishio, Yoshiyuki

2014-12-19

We fabricate thermoplastic films of chitin burtyrate (ChB)/poly(ɛ-caprolactone) (PCL) blends with different degree of miscibility (miscible (M), partially miscible (PM), and immiscible (IM)), and examined the feasibility as a cell scaffold system through evaluating mechanical properties and cytocompatibility. We found a remediation of the brittleness and an increase in ductility of ChB by blending PCL for the M and PM blends. The blend films were subjected to alkaline hydrolysis (2-M NaOH/37°C/48 h) with expectation of the improvement of the surface hydrophilicity and cell accessibility. ATR-FTIR spectroscopy of the alkaline-treated PM and IM films revealed that PCL component and ester side-chains of acyl chitin were selectively removed from the surface domain. L929 fibroblast cells well adhered and proliferated on these films. Therefore, the materials possess a great potential for the utilization as a thermoplastic cell scaffold in tissue engineering by adequate selection of the degree of miscibility and post treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Gold silver alloy nanoparticles (GSAN): an imaging probe for breast cancer screening with dual-energy mammography or computed tomography

NASA Astrophysics Data System (ADS)

Naha, Pratap C.; Lau, Kristen C.; Hsu, Jessica C.; Hajfathalian, Maryam; Mian, Shaameen; Chhour, Peter; Uppuluri, Lahari; McDonald, Elizabeth S.; Maidment, Andrew D. A.; Cormode, David P.

2016-07-01

Earlier detection of breast cancer reduces mortality from this disease. As a result, the development of better screening techniques is a topic of intense interest. Contrast-enhanced dual-energy mammography (DEM) is a novel technique that has improved sensitivity for cancer detection. However, the development of contrast agents for this technique is in its infancy. We herein report gold-silver alloy nanoparticles (GSAN) that have potent DEM contrast properties and improved biocompatibility. GSAN formulations containing a range of gold : silver ratios and capped with m-PEG were synthesized and characterized using various analytical methods. DEM and computed tomography (CT) phantom imaging showed that GSAN produced robust contrast that was comparable to silver alone. Cell viability, reactive oxygen species generation and DNA damage results revealed that the formulations with 30% or higher gold content are cytocompatible to Hep G2 and J774A.1 cells. In vivo imaging was performed in mice with and without breast tumors. The results showed that GSAN produce strong DEM and CT contrast and accumulated in tumors. Furthermore, both in vivo imaging and ex vivo analysis indicated the excretion of GSAN via both urine and feces. In summary, GSAN produce strong DEM and CT contrast, and has potential for both blood pool imaging and for breast cancer screening.Earlier detection of breast cancer reduces mortality from this disease. As a result, the development of better screening techniques is a topic of intense interest. Contrast-enhanced dual-energy mammography (DEM) is a novel technique that has improved sensitivity for cancer detection. However, the development of contrast agents for this technique is in its infancy. We herein report gold-silver alloy nanoparticles (GSAN) that have potent DEM contrast properties and improved biocompatibility. GSAN formulations containing a range of gold : silver ratios and capped with m-PEG were synthesized and characterized using various

Synthesis of highly stable cyanine-dye-doped silica nanoparticle for biological applications

NASA Astrophysics Data System (ADS)

Lian, Ying; Ding, Long-Jiang; Zhang, Wei; Zhang, Xiao-ai; Zhang, Ying-Lu; Lin, Zhen-zhen; Wang, Xu-dong

2018-07-01

Cyanine dyes are widely used in biological labeling and imaging because of their narrow near infrared emission, good brightness and high flexibility in functionalization, which not only enables multiplex analysis and multi-color imaging, but also greatly reduces autofluorescence from biological matter and increases signal-to-noise ratio. Unfortunately, their poor chemical- and photo-stability strongly limits their applications. The incorporation of cyanine dyes in silica nanoparticles provides a solution to the problem. On one hand, the incorporation of cyanine dyes in silica matrix can enhance their chemical- and photo-stability and increase brightness of the nanomaterials. On the other hand, silica matrix provides an optimized condition to host the dye, which helps to maintain their fluorescent properties during application. In addition, the well-established silane technique provides numerous functionalities for diverse applications. However, commercially available cyanine dyes are not very stable at high alkaline conditions, which will gradually lose their fluorescence over time. Our results showed that cyanine dyes are very vulnerable in the reverse micelle system, in which they will lose their fluorescence in less than half an hour. The existence of surfactant could greatly promote degradation of cyanine dyes. Fluorescent silica nanoparticles cannot be obtained at the high alkaline condition with the existence of surfactant. In contrast, the cyanine dyes are relatively stable in Stöber media. Owing to the fast formation of silica particles in Stöber media, the exposure time of cyanine dye in alkaline solution was greatly reduced, and highly fluorescent particles with good morphology and size distribution could be obtained via Stöber approach. However, the increasing water content in the Stöber could reduce the stability of cyanine dyes, which should be avoided. This research here provides a clear guidance on how to successfully synthesize cyanine dye

A statin-loaded reconstituted high-density lipoprotein nanoparticle inhibits atherosclerotic plaque inflammation

NASA Astrophysics Data System (ADS)

Duivenvoorden, Raphaël; Tang, Jun; Cormode, David P.; Mieszawska, Aneta J.; Izquierdo-Garcia, David; Ozcan, Canturk; Otten, Maarten J.; Zaidi, Neeha; Lobatto, Mark E.; van Rijs, Sarian M.; Priem, Bram; Kuan, Emma L.; Martel, Catherine; Hewing, Bernd; Sager, Hendrik; Nahrendorf, Matthias; Randolph, Gwendalyn J.; Stroes, Erik S. G.; Fuster, Valentin; Fisher, Edward A.; Fayad, Zahi A.; Mulder, Willem J. M.

2014-01-01

Inflammation is a key feature of atherosclerosis and a target for therapy. Statins have potent anti-inflammatory properties but these cannot be fully exploited with oral statin therapy due to low systemic bioavailability. Here we present an injectable reconstituted high-density lipoprotein (rHDL) nanoparticle carrier vehicle that delivers statins to atherosclerotic plaques. We demonstrate the anti-inflammatory effect of statin-rHDL in vitro and show that this effect is mediated through the inhibition of the mevalonate pathway. We also apply statin-rHDL nanoparticles in vivo in an apolipoprotein E-knockout mouse model of atherosclerosis and show that they accumulate in atherosclerotic lesions in which they directly affect plaque macrophages. Finally, we demonstrate that a 3-month low-dose statin-rHDL treatment regimen inhibits plaque inflammation progression, while a 1-week high-dose regimen markedly decreases inflammation in advanced atherosclerotic plaques. Statin-rHDL represents a novel potent atherosclerosis nanotherapy that directly affects plaque inflammation.

Efficient Intracellular Delivery of Molecules with High Cell Viability Using Nanosecond-Pulsed Laser-Activated Carbon Nanoparticles

PubMed Central

2015-01-01

Conventional physical and chemical methods that efficiently deliver molecules into cells are often associated with low cell viability. In this study, we evaluated the cellular effects of carbon nanoparticles believed to emit photoacoustic waves due to nanosecond-pulse laser activation to test the hypothesis that this method could achieve efficient intracellular delivery while maintaining high cell viability. Suspensions of DU145 human prostate carcinoma cells, carbon black (CB) nanoparticles, and calcein were exposed to 5–9 ns long laser pulses of near-infrared (1064 nm wavelength) light and then analyzed by flow cytometry for intracellular uptake of calcein and cell viability by propidium iodide staining. We found that intracellular uptake increased and in some cases saturated at high levels with only small losses in cell viability as a result of increasing laser fluence, laser exposure time, and as a unifying parameter, the total laser energy. Changing interpulse spacing between 0.1 and 10 s intervals showed no significant change in bioeffects, suggesting that the effects of each pulse were independent when spaced by at least 0.1 s intervals. Pretreatment of CB nanoparticles to intense laser exposure followed by mixing with cells also had no significant effect on uptake or viability. Similar uptake and viability were seen when CB nanoparticles were substituted with India ink, when DU145 cells were substituted with H9c2 rat cardiomyoblast cells, and when calcein was substituted with FITC-dextran. The best laser exposure conditions tested led to 88% of cells with intracellular uptake and close to 100% viability, indicating that nanosecond-pulse laser-activated carbon nanoparticles can achieve efficient intracellular delivery while maintaining high cell viability. PMID:24547946

Highly stabilized gadolinium chelates functionalized on metal nanoparticles as magnetic resonance imaging contrast agent

NASA Astrophysics Data System (ADS)

Siddiqui, Talha S.

Magnetic resonance imaging (MRI) is a non-invasive method for imaging and diagnosing tissue damage, organ function and the vascular system. Magnevist(TM) a complex of diethylenetriaminepentaacetic acid (DTPA) and Gd3+ is a clinically approved contrast agent for MRI. A derivative of DTPA was formed by the addition of two cysteine groups (DTPA-L-Cys) through amide linkage. The Gd complex of this ligand bonds with the silver surfaces through the cysteine thiols. GdDTPA-L-Cys was bound to ˜10nm diameter Ag nanoparticles for use as a multifunctional MRI contrast agent. The ligand and complex were characterized by 1H and 13C NMR, ESI-MS and IR spectroscopy. The silver construct was characterized by TEM, TGA and UV-Vis absorption spectra. The per metal complex r1 relaxivity of GdDTPA-L-Cys{Ag} greater than that of Magnavist(TM) with the same molarity for both compounds. The synthesis of a DTPA derivative is described that allows it to bind to silver or gold nanoparticles through a single thiol linkage (DTPASH). The resulting Gd complex, GdDTPASH, was bound to Ag nanoparticles to create a single monolayer on the surface. The construct was further stabilized in buffered solution with the addition of a thiolated PEG chain. The highly stabilized nanoparticle construct delivers a high payload of Gd compelex and is an effective T1 brightening agent. The production of this type of construct opens the way for engineered multimodal MRI contrast agents.

Recent Advances in Inorganic Nanoparticle-Based NIR Luminescence Imaging: Semiconductor Nanoparticles and Lanthanide Nanoparticles.

PubMed

Kim, Dokyoon; Lee, Nohyun; Park, Yong Il; Hyeon, Taeghwan

2017-01-18

Several types of nanoparticle-based imaging probes have been developed to replace conventional luminescent probes. For luminescence imaging, near-infrared (NIR) probes are useful in that they allow deep tissue penetration and high spatial resolution as a result of reduced light absorption/scattering and negligible autofluorescence in biological media. They rely on either an anti-Stokes or a Stokes shift process to generate luminescence. For example, transition metal-doped semiconductor nanoparticles and lanthanide-doped inorganic nanoparticles have been demonstrated as anti-Stokes shift-based agents that absorb NIR light through two- or three-photon absorption process and upconversion process, respectively. On the other hand, quantum dots (QDs) and lanthanide-doped nanoparticles that emit in NIR-II range (∼1000 to ∼1350 nm) were suggested as promising Stokes shift-based imaging agents. In this topical review, we summarize and discuss the recent progress in the development of inorganic nanoparticle-based luminescence imaging probes working in NIR range.

Nanoparticle self-assembly by a highly stable recombinant spider wrapping silk protein subunit.

PubMed

Xu, Lingling; Tremblay, Marie-Laurence; Orrell, Kathleen E; Leclerc, Jérémie; Meng, Qing; Liu, Xiang-Qin; Rainey, Jan K

2013-10-01

Artificial spider silk proteins may form fibers with exceptional strength and elasticity. Wrapping silk, or aciniform silk, is the toughest of the spider silks, and has a very different protein composition than other spider silks. Here, we present the characterization of an aciniform protein (AcSp1) subunit named W1, consisting of one AcSp1 199 residue repeat unit from Argiope trifasciata. The structural integrity of recombinant W1 is demonstrated in a variety of buffer conditions and time points. Furthermore, we show that W1 has a high thermal stability with reversible denaturation at ∼71°C and forms self-assembled nanoparticle in near-physiological conditions. W1 therefore represents a highly stable and structurally robust module for protein-based nanoparticle formation. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Development of Ti-Nb-Zr alloys with high elastic admissible strain for temporary orthopedic devices.

PubMed

Ozan, Sertan; Lin, Jixing; Li, Yuncang; Ipek, Rasim; Wen, Cuie

2015-07-01

A new series of beta Ti-Nb-Zr (TNZ) alloys with considerable plastic deformation ability during compression test, high elastic admissible strain, and excellent cytocompatibility have been developed for removable bone tissue implant applications. TNZ alloys with nominal compositions of Ti-34Nb-25Zr, Ti-30Nb-32Zr, Ti-28Nb-35.4Zr and Ti-24.8Nb-40.7Zr (wt.% hereafter) were fabricated using the cold-crucible levitation technique, and the effects of alloying element content on their microstructures, mechanical properties (tensile strength, yield strength, compressive yield strength, Young's modulus, elastic energy, toughness, and micro-hardness), and cytocompatibilities were investigated and compared. Microstructural examinations revealed that the TNZ alloys consisted of β phase. The alloy samples displayed excellent ductility with no cracking, or fracturing during compression tests. Their tensile strength, Young's modulus, elongation at rupture, and elastic admissible strain were measured in the ranges of 704-839 MPa, 62-65 GPa, 9.9-14.8% and 1.08-1.31%, respectively. The tensile strength, Young's modulus and elongation at rupture of the Ti-34Nb-25Zr alloy were measured as 839 ± 31.8 MPa, 62 ± 3.6 GPa, and 14.8 ± 1.6%, respectively; this alloy exhibited the elastic admissible strain of approximately 1.31%. Cytocompatibility tests indicated that the cell viability ratios (CVR) of the alloys are greater than those of the control group; thus the TNZ alloys possess excellent cytocompatibility. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

High yield production of long branched Au nanoparticles characterized by atomic resolution transmission electron microscopy

PubMed Central

Mayoral, Alvaro; Magen, Cesar; Jose-Yacaman, Miguel

2011-01-01

Long multi-branched gold nanoparticles have been synthesized in a very high yield through a facile synthesis combining two different capping agents. The stability of these materials with the time has been tested and their characterization have been performed by diverse advanced electron microscopy techniques, paying special attention to aberration corrected transmission electron microscopy in order to unambiguously analyze the surface structure of the branches and provide insights for the formation of stellated gold nanoparticles. PMID:22125420

Alloy nanoparticle synthesis using ionizing radiation

DOEpatents

Nenoff, Tina M [Sandia Park, NM; Powers, Dana A [Albuquerque, NM; Zhang, Zhenyuan [Durham, NC

2011-08-16

A method of forming stable nanoparticles comprising substantially uniform alloys of metals. A high dose of ionizing radiation is used to generate high concentrations of solvated electrons and optionally radical reducing species that rapidly reduce a mixture of metal ion source species to form alloy nanoparticles. The method can make uniform alloy nanoparticles from normally immiscible metals by overcoming the thermodynamic limitations that would preferentially produce core-shell nanoparticles.

Sorting process of nanoparticles and applications of same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tyler, Timothy P.; Henry, Anne-Isabelle; Van Duyne, Richard P.

In one aspect of the present invention, a method for sorting nanoparticles includes preparing a high-viscosity density gradient medium filled in a container, dispersing nanoparticles into an aqueous solution to form a suspension of the nanoparticles, each nanoparticle having one or more cores and a shell encapsulating the one or more cores, layering the suspension of the nanoparticles on the top of the high-viscosity density gradient medium in the container, and centrifugating the layered suspension of the nanoparticles on the top of the high-viscosity density gradient medium in the container at a predetermined speed for a predetermined period of timemore » to form a gradient of fractions of the nanoparticles along the container, where each fraction comprises nanoparticles in a respective one of aggregation states of the nanoparticles.« less

Interference-free Micro/nanoparticle Cell Engineering by Use of High-Throughput Microfluidic Separation.

PubMed

Yeo, David C; Wiraja, Christian; Zhou, Yingying; Tay, Hui Min; Xu, Chenjie; Hou, Han Wei

2015-09-23

Engineering cells with active-ingredient-loaded micro/nanoparticles is becoming increasingly popular for imaging and therapeutic applications. A critical yet inadequately addressed issue during its implementation concerns the significant number of particles that remain unbound following the engineering process, which inadvertently generate signals and impart transformative effects onto neighboring nontarget cells. Here we demonstrate that those unbound micro/nanoparticles remaining in solution can be efficiently separated from the particle-labeled cells by implementing a fast, continuous, and high-throughput Dean flow fractionation (DFF) microfluidic device. As proof-of-concept, we applied the DFF microfluidic device for buffer exchange to sort labeled suspension cells (THP-1) from unbound fluorescent dye and dye-loaded micro/nanoparticles. Compared to conventional centrifugation, the depletion efficiency of free dyes or particles was improved 20-fold and the mislabeling of nontarget bystander cells by free particles was minimized. The microfluidic device was adapted to further accommodate heterogeneous-sized mesenchymal stem cells (MSCs). Complete removal of unbound nanoparticles using DFF led to the usage of engineered MSCs without exerting off-target transformative effects on the functional properties of neighboring endothelial cells. Apart from its effectiveness in removing free particles, this strategy is also efficient and scalable. It could continuously process cell solutions with concentrations up to 10(7) cells·mL(-1) (cell densities commonly encountered during cell therapy) without observable loss of performance. Successful implementation of this technology is expected to pave the way for interference-free clinical application of micro/nanoparticle engineered cells.

High-energy ball milling technique for ZnO nanoparticles as antibacterial material

PubMed Central

Salah, Numan; Habib, Sami S; Khan, Zishan H; Memic, Adnan; Azam, Ameer; Alarfaj, Esam; Zahed, Nabeel; Al-Hamedi, Salim

2011-01-01

Nanoparticles of zinc oxide (ZnO) are increasingly recognized for their utility in biological applications. In this study, the high-energy ball milling (HEBM) technique was used to produce nanoparticles of ZnO from its microcrystalline powder. Four samples were ball milled for 2, 10, 20, and 50 hours, respectively. The structural and optical modifications induced in the ‘as synthesized’ nanomaterials were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), and photoluminescence emission spectra (PL). SEM and TEM results show a gradual decrease in particle size from around 600 to ∼30 nm, with increased milling time. The initial microstructures had random shapes, while the final shape became quite spherical. XRD analysis showed ZnO in a hexagonal structure, broadening in the diffracted peaks and going from larger to smaller particles along with a relaxation in the lattice constant c. The value of c was found to increase from 5.204 to 5.217 Å with a decrease in particle size (600 to ∼30 nm). PL result showed a new band at around 365 nm, whose intensity is found to increase as the particles size decreases. These remarkable structural and optical modifications induced in ZnO nanoparticles might prove useful for various applications. The increase in c value is an important factor for increasing the antibacterial effects of ZnO, suggesting that the HEBM technique is quite suitable for producing these nanoparticles for this purpose. PMID:21720499

Efficient neutron generation from solid-nanoparticle explosions driven by DPSSL-pumped high-repetition rate femtosecond laser pulse

NASA Astrophysics Data System (ADS)

Watari, T.; Matsukado, K.; Sekine, T.; Takeuchi, Y.; Hatano, Y.; Yoshimura, R.; Satoh, N.; Nishihara, K.; Takagi, M.; Kawashima, T.

2016-03-01

We propose novel neutron source using high-intensity laser based on the cluster fusion scheme. We developed DPSSL-pumped high-repetition-rate 20-TW laser system and solid nanoparticle target for neutron generation demonstration. In our neutron generation experiment, high-energy deuterons were generated from coulomb explosion of CD solid- nanoparticles and neutrons were generated by DD fusion reaction. Efficient and stable neutron generation was obtained by irradiating an intense femtosecond laser pulse of >2×1018 W/cm2. A yield of ∼105 neutrons per shot was stably observed during 0.1-1 Hz continuous operation.

Anomalous thermal hysteresis in the high-field magnetic moments of magnetic nanoparticles embedded in multi-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Zhao, Guo-Meng; Wang, Jun; Ren, Yang; Beeli, Pieder

2012-02-01

We report high-temperature (300-1120 K) magnetic properties of Fe and Fe3O4 nanoparticles embedded in multi-walled carbon nanotubes. We unambiguously show that the magnetic moments of Fe and Fe3O4 nanoparticles are seemingly enhanced by a factor of about 3 compared with what they would be expected to have for free (unembedded) magnetic nanoparticles. What is more intriguing is that the enhanced moments were completely lost when the sample was heated up to 1120 K and the lost moments at 1120 K were completely recovered through several thermal cycles below 1020 K. The anomalous thermal hysteresis of the high-field magnetic moments is unlikely to be explained by existing physical models except for the high-field paramagnetic Meissner effect due to the existence of ultrahigh temperature superconductivity in the multi-walled carbon nanotubes.

Long-term delivery of brain-derived neurotrophic factor (BDNF) from nanoporous silica nanoparticles improves the survival of spiral ganglion neurons in vitro

PubMed Central

Warwas, Dawid P.; Ehlert, Nina; Lenarz, Thomas; Warnecke, Athanasia; Behrens, Peter

2018-01-01

Sensorineural hearing loss (SNHL) can be overcome by electrical stimulation of spiral ganglion neurons (SGNs) via a cochlear implant (CI). Restricted CI performance results from the spatial gap between the SGNs and the electrode, but the efficacy of CI is also limited by the degeneration of SGNs as one consequence of SHNL. In the healthy cochlea, the survival of SGNs is assured by endogenous neurotrophic support. Several applications of exogenous neurotrophic supply have been shown to reduce SGN degeneration in vitro and in vivo. In the present study, nanoporous silica nanoparticles (NPSNPs), with an approximate diameter of <100 nm, were loaded with the brain-derived neurotrophic factor (BDNF) to test their efficacy as long-term delivery system for neurotrophins. The neurotrophic factor was released constantly from the NPSNPs over a release period of 80 days when the surface of the nanoparticles had been modified with amino groups. Cell culture investigations with NIH3T3 fibroblasts attest a good general cytocompatibility of the NPSNPs. In vitro experiments with SGNs indicate a significantly higher survival rate of SGNs in cell cultures that contained BDNF-loaded nanoparticles compared to the control culture with unloaded NPSNPs (p<0.001). Importantly, also the amounts of BDNF released up to a time period of 39 days increased the survival rate of SGNs. Thus, NPSNPs carrying BDNF are suitable for the treatment of inner ear disease and for the protection and the support of SGNs. Their nanoscale nature and the fact that a direct contact of the nanoparticles and the SGNs is not necessary for neuroprotective effects, should allow for the facile preparation of nanocomposites, e.g., with biocompatible polymers, to install coatings on implants for the realization of implant-based growth factor delivery systems. PMID:29584754

Synthesis and Characterization of Biomimetic High Density Lipoprotein Nanoparticles To Treat Lymphoma

NASA Astrophysics Data System (ADS)

Damiano, Marina Giacoma

High density lipoproteins (HDLs), natural nanoparticles that function as vehicles for cholesterol transport, have enhanced uptake by several human cancers. This uptake is mediated, in part, by the high affinity HDL receptor, scavenger receptor B-1 (SR-B1). More specifically, studies show that the rate of cellular proliferation of lymphoma, a cancer of the lymphocytes, is directly proportional to the amount of HDL-cholesterol available. Thus, targeting of HDL-cholesterol uptake by these cells could be an effective therapeutic approach that may have lower toxicity to healthy cells compared to conventional therapies. Biomimetic HDL can be synthesized using a gold nanoparticle template (HDL-AuNPs), which provides control over size, shape, and surface chemistry. Like their natural counterparts, HDL-AuNPs sequester cholesterol. However, since the gold nanoparticle replaces the cholesterol core of natural HDL, HDL-AuNPs inherently deliver less cholesterol. We show that HDL-AuNPs are able to induce dose dependent apoptosis in B cell lymphoma cell lines and reduce tumor volume following systemic administration to mice bearing B cell lymphoma tumors. Furthermore, HDL-AuNPs are neither toxic to healthy human lymphocytes (SR-B1-), nor to hepatocytes and macrophages (SR-B1+), which are cells naturally encountered by HDLs. Manipulation of cholesterol flux and targeting of SR-B1 are responsible for the efficacy of HDL-AuNPs against B cell lymphoma. HDL-AuNPs could be used to treat B cell lymphomas and other diseases that involve pathologic accumulation of cholesterol. Titanium dioxide nanoparticle (TiO2 NP) core HDLs (HDL-TiO 2 NPs) have been synthesized for high resolution cellular localization studies and for future use as a therapeutic and imaging agent. In initial studies, HDL-TiO(2 NPs display maximum uptake in B cell lymphoma cell lines. X-ray fluorescence microscopy studies show interaction between HDL-TiO2 NPs and cells 10 minutes after treatment and internalization after

In situ generation of highly dispersed metal nanoparticles on two-dimensional layered SiO2 by topotactic structure conversion and their superior catalytic activity

NASA Astrophysics Data System (ADS)

Chen, Zhe; Jia, Da-Shuang; Zhou, Yue; Hao, Jiang; Liang, Yu; Cui, Zhi-Min; Song, Wei-Guo

2018-03-01

Metal nanoparticles such as Ag, Cu and Fe are effective catalysts for many reactions, whereas a facile method to prepare metal nanoparticles with high uniformed dispersion is still desirable. Herein, the topotactic structure conversion of layered silicate, RUB-15, was utilized to support metal nanoparticles. Through simple ion-exchange and following calcination step, metal nanoparticles were generated in situ inside the interlayer space of layered silica, and the topotactic structure conversion process assured nano-sized and highly uniformed dispersion of metal nanoparticles. The obtained Ag/SiO2 composite showed superior catalytic activity for the reduction of 4-nitrophenol (4-NP) and methylene blue (MB), with a rate constant as high as 0.0607 s-1 and 0.0778 s-1. The simple and universal synthesis method as well as high activity of the product composite endow the strategy good application prospect.

Pure colloidal metal and ceramic nanoparticles from high-power picosecond laser ablation in water and acetone.

PubMed

Bärsch, Niko; Jakobi, Jurij; Weiler, Sascha; Barcikowski, Stephan

2009-11-04

The generation of colloids by laser ablation of solids in a liquid offers a nearly unlimited material variety and a high purity as no chemical precursors are required. The use of novel high-power ultra-short-pulsed laser systems significantly increases the production rates even in inflammable organic solvents. By applying an average laser power of 50 W and pulse durations below 10 ps, up to 5 mg min(-1) of nanoparticles have been generated directly in acetone, marking a breakthrough in productivity of ultra-short-pulsed laser ablation in liquids. The produced colloids remain stable for more than six months. In the case of yttria-stabilized zirconia ceramic, the nanoparticles retain the tetragonal crystal structure of the ablated target. Laser beam self-focusing plays an important role, as a beam radius change of 2% on the liquid surface can lead to a decrease of nanoparticle production rates of 90% if the target position is not re-adjusted.

Co-delivery of a hydrophobic small molecule and a hydrophilic peptide by porous silicon nanoparticles.

PubMed

Liu, Dongfei; Bimbo, Luis M; Mäkilä, Ermei; Villanova, Francesca; Kaasalainen, Martti; Herranz-Blanco, Barbara; Caramella, Carla M; Lehto, Vesa-Pekka; Salonen, Jarno; Herzig, Karl-Heinz; Hirvonen, Jouni; Santos, Hélder A

2013-09-10

Nanoparticulate drug delivery systems offer remarkable opportunities for clinical treatment. However, there are several challenges when they are employed to deliver multiple cargos/payloads, particularly concerning the synchronous delivery of small molecular weight drugs and relatively larger peptides. Since porous silicon (PSi) nanoparticles (NPs) can easily contain high payloads of drugs with various properties, we evaluated their carrier potential in multi-drug delivery for co-loading of the hydrophobic drug indomethacin and the hydrophilic human peptide YY3-36 (PYY3-36). Sequential loading of these two drugs into the PSi NPs enhanced the drug release rate of each drug and also their amount permeated across Caco-2 and Caco-2/HT29 cell monolayers. Regardless of the loading approach used, dual or single, the drug permeation profiles were in good correlation with their drug release behaviour. Furthermore, the permeation studies indicated the critical role of the mucus intestinal layer and the paracellular resistance in the permeation of the therapeutic compounds across the intestinal wall. Loading with PYY3-36 also greatly improved the cytocompatibility of the PSi NPs. Conformational analysis indicated that the PYY3-36 could still display biological activity after release from the PSi NPs and permeation across the intestinal cell monolayers. These results are the first demonstration of the promising potential of PSi NPs for simultaneous multi-drug delivery of both hydrophobic and hydrophilic compounds. Copyright © 2013 Elsevier B.V. All rights reserved.

Highly Transparent Wafer-Scale Synthesis of Crystalline WS2 Nanoparticle Thin Film for Photodetector and Humidity-Sensing Applications.

PubMed

Pawbake, Amit S; Waykar, Ravindra G; Late, Dattatray J; Jadkar, Sandesh R

2016-02-10

In the present investigation, we report a one-step synthesis method of wafer-scale highly crystalline tungsten disulfide (WS2) nanoparticle thin film by using a modified hot wire chemical vapor deposition (HW-CVD) technique. The average size of WS2 nanoparticle is found to be 25-40 nm over an entire 4 in. wafer of quartz substrate. The low-angle XRD data of WS2 nanoparticle shows the highly crystalline nature of sample along with orientation (002) direction. Furthermore, Raman spectroscopy shows two prominent phonon vibration modes of E(1)2g and A1g at ∼356 and ∼420 cm(-1), respectively, indicating high purity of material. The TEM analysis shows good crystalline quality of sample. The synthesized WS2 nanoparticle thin film based device shows good response to humidity and good photosensitivity along with good long-term stability of the device. It was found that the resistance of the films decreases with increasing relative humidity (RH). The maximum humidity sensitivity of 469% along with response time of ∼12 s and recovery time of ∼13 s were observed for the WS2 thin film humidity sensor device. In the case of photodetection, the response time of ∼51 s and recovery time of ∼88 s were observed with sensitivity ∼137% under white light illumination. Our results open up several avenues to grow other transition metal dichalcogenide nanoparticle thin film for large-area nanoelectronics as well as industrial applications.

Multifunctional Nucleus-targeting Nanoparticles with Ultra-high Gene Transfection Efficiency for In Vivo Gene Therapy

PubMed Central

Li, Ling; Li, Xia; Wu, Yuzhe; Song, Linjiang; Yang, Xi; He, Tao; Wang, Ning; Yang, Suleixin; Zeng, Yan; Wu, Qinjie; Qian, Zhiyong; Wei, Yuquan; Gong, Changyang

2017-01-01

Cancer stem cell-like cells (CSCL) are responsible for tumor recurrence associated with conventional therapy (e.g. surgery, radiation, and chemotherapy). Here, we developed a novel multifunctional nucleus-targeting nanoparticle-based gene delivery system which is capable of targeting and eradicating CSCL. These nanoparticles can facilitate efficient endosomal escape and spontaneously penetrate into nucleus without additional nuclear localization signal. They also induced extremely high gene transfection efficiency (>95%) even in culture medium containing 30% serum, which significantly surpassed that of some commercial transfection reagents, such as Lipofectamine 2000 and Lipofectamine 3000 etc. Especially, when loaded with the TRAIL gene, this system mediated remarkable depletion of CSCL. Upon systemic administration, the nanoparticles accumulated in tumor sites while sparing the non-cancer tissues and significantly inhibited the growth of tumors with no evident systemic toxicity. Taken together, our results suggest that these novel multifunctional, nucleus-targeting nanoparticles are a very promising in vivo gene delivery system capable of targeting CSCL and represent a new treatment candidate for improving the survival of cancer patients. PMID:28529641

Highly stable noble-metal nanoparticles in tetraalkylphosphonium ionic liquids for in situ catalysis.

PubMed

Banerjee, Abhinandan; Theron, Robin; Scott, Robert W J

2012-01-09

Gold and palladium nanoparticles were prepared by lithium borohydride reduction of the metal salt precursors in tetraalkylphosphonium halide ionic liquids in the absence of any organic solvents or external nanoparticle stabilizers. These colloidal suspensions remained stable and showed no nanoparticle agglomeration over many months. A combination of electrostatic interactions between the coordinatively unsaturated metal nanoparticle surface and the ionic-liquid anions, bolstered by steric protection offered by the bulky alkylated phosphonium cations, is likely to be the reason behind such stabilization. The halide anion strongly absorbs to the nanoparticle surface, leading to exceptional nanoparticle stability in halide ionic liquids; other tetraalkylphosphonium ionic liquids with non-coordinating anions, such as tosylate and hexafluorophosphate, show considerably lower affinities towards the stabilization of nanoparticles. Palladium nanoparticles stabilized in the tetraalkylphosphonium halide ionic liquid were stable, efficient, and recyclable catalysts for a variety of hydrogenation reactions at ambient pressures with sustained activity. Aerial oxidation of the metal nanoparticles occurred over time and was readily reversed by re-reduction of oxidized metal salts. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High density flux of Co nanoparticles produced by a simple gas aggregation apparatus.

PubMed

Landi, G T; Romero, S A; Santos, A D

2010-03-01

Gas aggregation is a well known method used to produce clusters of different materials with good size control, reduced dispersion, and precise stoichiometry. The cost of these systems is relatively high and they are generally dedicated apparatuses. Furthermore, the usual sample production speed of these systems is not as fast as physical vapor deposition devices posing a problem when thick samples are needed. In this paper we describe the development of a multipurpose gas aggregation system constructed as an adaptation to a magnetron sputtering system. The cost of this adaptation is negligible and its installation and operation are both remarkably simple. The gas flow for flux in the range of 60-130 SCCM (SCCM denotes cubic centimeter per minute at STP) is able to completely collimate all the sputtered material, producing spherical nanoparticles. Co nanoparticles were produced and characterized using electron microscopy techniques and Rutherford back-scattering analysis. The size of the particles is around 10 nm with around 75 nm/min of deposition rate at the center of a Gaussian profile nanoparticle beam.

Photoinitiated polymerization of PEG-diacrylate with lithium phenyl-2,4,6-trimethylbenzoylphosphinate: polymerization rate and cytocompatibility

PubMed Central

Fairbanks, Benjamin D.; Schwartz, Michael P.; Bowman, Christopher N.; Anseth, Kristi S.

2009-01-01

Due to mild reaction conditions and temporal and spatial control over material formation, photopolymerization has become a valuable technique for the encapsulation of living cells in three dimensional, hydrated, biomimetic materials. For such applications,2-hydroxy-1-[4-(2-hydroxyethoxy) phenyl]-2-methyl-1-propanone (I2959) is the most commonly used photoinitiator (by virtue of its moderate water solubility), yet this initiator has an absorption spectrum that is poorly matched with wavelengths of light generally regarded as benign to living cells, limiting the rate at which it may initiate polymerization in their presence. In contrast, acylphosphine oxide photoinitiators, generally exhibit absorption spectra at wavelengths suitable for cell encapsulation, yet commercially available initiators of this class have low water solubility. Here, a water soluble lithium acylphosphinate salt is evaluated for its ability to polymerize diacrylated poly(ethylene glycol) (PEGDA) monomers rapidly into hydrogels, while maintaining high viability during direct encapsulation of cells. Through rheometric measurements, the time to reach gelation of a PEGDA solution with the phosphinate initiator is one tenth the time for that using I2959 at similar concentrations, when exposed to 365 nm light. Further, polymerization with the phosphinate initiator at 405 nm visible light exposure is achieved with low initiator concentrations and light intensities, precluded in polymerizations initiated with I2959 by its absorbance profile. When examined 24 hours after encapsulation, survival rates of human neonatal fibroblasts encapsulated in hydrogels polymerized with the phosphinate initiator exceed 95%, demonstrating the cytocompatibility of this initiating system. PMID:19783300

Zein/Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) electrospun blend fiber scaffolds: Preparation, characterization and cytocompatibility.

PubMed

Zhijiang, Cai; Qin, Zhang; Xianyou, Song; Yuanpei, Liu

2017-02-01

In the present work, a series of Zein/Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) blend fiber scaffolds have been prepared by electrospinning method. The electrospun fibers showed a circular and uniform morphology with random distribution. The blend fiber scaffolds possessed well interconnected porous fibrous network structure with high porosity and large aspect surface areas. The FTIR and XPS spectra of Zein/P(3HB-co-4HB) blend fibers demonstrated the same characteristics to that of pure Zein and P(3HB-co-4HB) electrospun fibers. However, Zein might hinder the crystallization of P(3HB-co-4HB) owing to the formation of weak intermolecular interactions, which can affect the preferential orientation of P(3HB-co-4HB) molecules. Only one glass transition temperature (Tg) can be detected for electrospun Zein/P(3HB-co-4HB) blend fiber scaffolds implying the miscibility of Zein and P(3HB-co-4HB) in the blend fibers. The Zein/P(3HB-co-4HB) blend fiber scaffolds showed about 50% of improvement in tensile strength and 400% of increase in elongation at break by increasing P(3HB-co-4HB) content from 20% to 80%. The cytocompatibility of the Zein/P(3HB-co-4HB) blend fiber scaffolds was preliminarily evaluated by cell culture in vitro. The as-prepared electrospun Zein/P(3HB-co-4HB) blend fiber scaffolds with the characteristics of good biocompatibility, excellent pore characteristic as well as sufficient mechanical properties should be more promising for applications as tissue engineering scaffold. Copyright © 2016 Elsevier B.V. All rights reserved.

Versatile Methodology to Encapsulate Gold Nanoparticles in PLGA Nanoparticles Obtained by Nano-Emulsion Templating.

PubMed

Fornaguera, Cristina; Feiner-Gracia, Natàlia; Dols-Perez, Aurora; García-Celma, Maria José; Solans, Conxita

2017-05-01

Gold nanoparticles have been proved useful for many biomedical applications, specifically, for their use as advanced imaging systems. However, they usually present problems related with stability and toxicity. In the present work, gold-nanoparticles have been encapsulated in polymeric nanoparticles using a novel methodology based on nano-emulsion templating. Firstly, gold nanoparticles have been transferred from water to ethyl acetate, a solvent classified as class III by the NIH guidelines (low toxic potential). Next, the formation of nano-emulsions loaded with gold nanoparticles has been performed using a low-energy, the phase inversion composition (PIC) emulsification method, followed by solvent evaporation giving rise to polymeric nanoparticles. Using this methodology, high concentrations of gold nanoparticles (>100 pM) have been encapsulated. Increasing gold nanoparticle concentration, nano-emulsion and nanoparticle sizes increase, resulting in a decrease on the stability. It is noteworthy that the designed nanoparticles did not produce cytotoxicity neither hemolysis at the required concentration. Therefore, it can be concluded that a novel and very versatile methodology has been developed for the production of polymeric nanoparticles loaded with gold nanoparticles. Graphical Abstract Schematic representation of AuNP-loaded polymeric nanoparticles preparation from nano-emulsion templating.

Nanostructured titanium-silver coatings with good antibacterial activity and cytocompatibility fabricated by one-step magnetron sputtering

NASA Astrophysics Data System (ADS)

Bai, Long; Hang, Ruiqiang; Gao, Ang; Zhang, Xiangyu; Huang, Xiaobo; Wang, Yueyue; Tang, Bin; Zhao, Lingzhou; Chu, Paul K.

2015-11-01

Bacterial infection and loosing are serious complications for biomedical implants in the orthopedic, dental, and other biomedical fields and the ideal implants should combine good antibacterial ability and bioactivity. In this study, nanostructured titanium-silver (Ti-Ag) coatings with different Ag contents (1.2 to 21.6 at%) are prepared on Ti substrates by magnetron sputtering. As the Ag concentration is increased, the coatings change from having dense columnar crystals to sparse ones and eventually no columnar structure. The Ti-Ag coatings can effectively kill Staphylococcus aureus during the first few days and remain moderately antibacterial after immersion for 75 days. Compared to pure Ti, the Ti-Ag coatings show good cytocompatibility as indicated by good osteoblast adhesion, proliferation, intracellular total protein synthesis, and alkaline phosphatase (ALP) activity. In addition, cell spreading, collagen secretion, and extracellular matrix mineralization are promoted on the coatings with the proper Ag contents due to the nanostructured morphological features. Our results indicate that favorable antibacterial activity and osseointegration ability can be simultaneously achieved by regulating the Ag contents in Ti-Ag coatings.

Growth graphene on silver-copper nanoparticles by chemical vapor deposition for high-performance surface-enhanced Raman scattering

NASA Astrophysics Data System (ADS)

Zhang, Xiumei; Xu, Shicai; Jiang, Shouzhen; Wang, Jihua; Wei, Jie; Xu, Shida; Gao, Shoubao; Liu, Hanping; Qiu, Hengwei; Li, Zhen; Liu, Huilan; Li, Zhenhua; Li, Hongsheng

2015-10-01

We present a graphene/silver-copper nanoparticle hybrid system (G/SCNPs) to be used as a high-performance surface-enhanced Raman scattering (SERS) substrate. The silver-copper nanoparticles wrapped by a monolayer graphene layer are directly synthesized on SiO2/Si substrate by chemical vapor deposition in a mixture of methane and hydrogen. The G/SCNPs shows excellent SERS enhancement activity and high reproducibility. The minimum detected concentration of R6G is as low as 10-10 M and the calibration curve shows a good linear response from 10-6 to 10-10 M. The date fluctuations from 20 positions of one SERS substrate are less than 8% and from 20 different substrates are less than 10%. The high reproducibility of the enhanced Raman signals could be due to the presence of an ultrathin graphene layer and uniform morphology of silver-copper nanoparticles. The use of G/SCNPs for detection of nucleosides extracted from human urine demonstrates great potential for the practical applications on a variety of detection in medicine and biotechnology field.

Bioactive bredigite coating with improved bonding strength, rapid apatite mineralization and excellent cytocompatibility.

PubMed

Yi, Deliang; Wu, Chengtie; Ma, Bing; Ji, Heng; Zheng, Xuebin; Chang, Jiang

2014-05-01

Previous studies have shown that bredigite (Ca7MgSi4O16) bioceramics possessed excellent biocompatibility, apatite-mineralization ability and mechanical properties. In this paper, the bredigite coating on Ti-6Al-4 V substrate was prepared by plasma spraying technique. The main compositions of the coating were bredigite crystal phase with small parts of amorphous phases. The bonding strength of the coating to Ti-6Al-4 V substrate reached 49.8 MPa, which was significantly higher than that of hydroxyapatite coating and other silicate-based bioceramic coatings prepared by same method. After immersed in simulated body fluid for 2 days, a distinct apatite layer was deposited on the surface of bredigite coating, indicating that the prepared bredigite coating has excellent apatite-mineralization ability. The prepared bredigite coating supported the attachment and proliferation of rabbit bone marrow stem cells. The proliferation level of bone marrow stem cells was significantly higher than that on the hydroxyapatite coating. Our further study showed that the released SiO4 (4-) and Mg(2+) ions from bredigite coating as well as the formed nano-apatite layer on the coating surface might mainly contribute to the improvement of cell proliferation. The results indicated that the bredigite coating may be applied on orthopedic implants due to its excellent bonding strength, apatite mineralization and cytocompatibility.

Antimicrobial activity of silver nanoparticles encapsulated in poly-N-isopropylacrylamide-based polymeric nanoparticles.

PubMed

Qasim, Muhammad; Udomluck, Nopphadol; Chang, Jihyun; Park, Hansoo; Kim, Kyobum

2018-01-01

In this study, we analyzed the antimicrobial activities of poly- N -isopropylacrylamide (pNIPAM)-based polymeric nanoparticles encapsulating silver nanoparticles (AgNPs). Three sizes of AgNP-encapsulating pNIPAM- and pNIPAM-NH 2 -based polymeric nanoparticles were fabricated. Highly stable and uniformly distributed AgNPs were encapsulated within polymeric nanoparticles via in situ reduction of AgNO 3 using NaBH 4 as the reducing agent. The formation and distribution of AgNPs was confirmed by UV-visible spectroscopy, transmission electron microscopy, and inductively coupled plasma optical emission spectrometry, respectively. Both polymeric nanoparticles showed significant bacteriostatic activities against Gram-negative ( Escherichia coli ) and Gram-positive ( Staphylococcus aureus ) bacteria depending on the nanoparticle size and amount of AgNO 3 used during fabrication.

Antimicrobial activity of silver nanoparticles encapsulated in poly-N-isopropylacrylamide-based polymeric nanoparticles

PubMed Central

Qasim, Muhammad; Udomluck, Nopphadol; Chang, Jihyun; Park, Hansoo; Kim, Kyobum

2018-01-01

In this study, we analyzed the antimicrobial activities of poly-N-isopropylacrylamide (pNIPAM)-based polymeric nanoparticles encapsulating silver nanoparticles (AgNPs). Three sizes of AgNP-encapsulating pNIPAM- and pNIPAM-NH2-based polymeric nanoparticles were fabricated. Highly stable and uniformly distributed AgNPs were encapsulated within polymeric nanoparticles via in situ reduction of AgNO3 using NaBH4 as the reducing agent. The formation and distribution of AgNPs was confirmed by UV-visible spectroscopy, transmission electron microscopy, and inductively coupled plasma optical emission spectrometry, respectively. Both polymeric nanoparticles showed significant bacteriostatic activities against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria depending on the nanoparticle size and amount of AgNO3 used during fabrication. PMID:29379284

Unusual multiscale mechanics of biomimetic nanoparticle hydrogels

DOE PAGES

Zhou, Yunlong; Damasceno, Pablo F.; Somashekar, Bagganahalli S.; ...

2018-01-12

Viscoelastic properties are central for gels and other materials. Simultaneously, high storage and loss moduli are difficult to attain due to their contrarian requirements to chemical structure. Biomimetic inorganic nanoparticles offer a promising toolbox for multiscale engineering of gel mechanics, but a conceptual framework for their molecular, nanoscale, mesoscale, and microscale engineering as viscoelastic materials is absent. Here we show nanoparticle gels with simultaneously high storage and loss moduli from CdTe nanoparticles. Viscoelastic figure of merit reaches 1.83 MPa exceeding that of comparable gels by 100–1000 times for glutathione-stabilized nanoparticles. The gels made from the smallest nanoparticles display the highestmore » stiffness, which was attributed to the drastic change of GSH configurations when nanoparticles decrease in size. A computational model accounting for the difference in nanoparticle interactions for variable GSH configurations describes the unusual trends of nanoparticle gel viscoelasticity. These observations are generalizable to other NP gels interconnected by supramolecular interactions and lead to materials with high-load bearing abilities and energy dissipation needed for multiple technologies.« less

Unusual multiscale mechanics of biomimetic nanoparticle hydrogels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Yunlong; Damasceno, Pablo F.; Somashekar, Bagganahalli S.

Viscoelastic properties are central for gels and other materials. Simultaneously, high storage and loss moduli are difficult to attain due to their contrarian requirements to chemical structure. Biomimetic inorganic nanoparticles offer a promising toolbox for multiscale engineering of gel mechanics, but a conceptual framework for their molecular, nanoscale, mesoscale, and microscale engineering as viscoelastic materials is absent. Here we show nanoparticle gels with simultaneously high storage and loss moduli from CdTe nanoparticles. Viscoelastic figure of merit reaches 1.83 MPa exceeding that of comparable gels by 100–1000 times for glutathione-stabilized nanoparticles. The gels made from the smallest nanoparticles display the highestmore » stiffness, which was attributed to the drastic change of GSH configurations when nanoparticles decrease in size. A computational model accounting for the difference in nanoparticle interactions for variable GSH configurations describes the unusual trends of nanoparticle gel viscoelasticity. These observations are generalizable to other NP gels interconnected by supramolecular interactions and lead to materials with high-load bearing abilities and energy dissipation needed for multiple technologies.« less

Zeolite Nanoparticles for Selective Sorption of Plasma Proteins

NASA Astrophysics Data System (ADS)

Rahimi, M.; Ng, E.-P.; Bakhtiari, K.; Vinciguerra, M.; Ahmad, H. Ali; Awala, H.; Mintova, S.; Daghighi, M.; Bakhshandeh Rostami, F.; de Vries, M.; Motazacker, M. M.; Peppelenbosch, M. P.; Mahmoudi, M.; Rezaee, F.

2015-11-01

The affinity of zeolite nanoparticles (diameter of 8-12 nm) possessing high surface area and high pore volume towards human plasma proteins has been investigated. The protein composition (corona) of zeolite nanoparticles has been shown to be more dependent on the plasma protein concentrations and the type of zeolites than zeolite nanoparticles concentration. The number of proteins present in the corona of zeolite nanoparticles at 100% plasma (in vivo state) is less than with 10% plasma exposure. This could be due to a competition between the proteins to occupy the corona of the zeolite nanoparticles. Moreover, a high selective adsorption for apolipoprotein C-III (APOC-III) and fibrinogen on the zeolite nanoparticles at high plasma concentration (100%) was observed. While the zeolite nanoparticles exposed to low plasma concentration (10%) exhibited a high selective adsorption for immunoglobulin gamma (i.e. IGHG1, IGHG2 and IGHG4) proteins. The zeolite nanoparticles can potentially be used for selectively capture of APOC-III in order to reduce the activation of lipoprotein lipase inhibition during hypertriglyceridemia treatment. The zeolite nanoparticles can be adapted to hemophilic patients (hemophilia A (F-VIII deficient) and hemophilia B (F-IX deficient)) with a risk of bleeding, and thus might be potentially used in combination with the existing therapy.

Zeolite Nanoparticles for Selective Sorption of Plasma Proteins.

PubMed

Rahimi, M; Ng, E-P; Bakhtiari, K; Vinciguerra, M; Ali Ahmad, H; Awala, H; Mintova, S; Daghighi, M; Bakhshandeh Rostami, F; de Vries, M; Motazacker, M M; Peppelenbosch, M P; Mahmoudi, M; Rezaee, F

2015-11-30

The affinity of zeolite nanoparticles (diameter of 8-12 nm) possessing high surface area and high pore volume towards human plasma proteins has been investigated. The protein composition (corona) of zeolite nanoparticles has been shown to be more dependent on the plasma protein concentrations and the type of zeolites than zeolite nanoparticles concentration. The number of proteins present in the corona of zeolite nanoparticles at 100% plasma (in vivo state) is less than with 10% plasma exposure. This could be due to a competition between the proteins to occupy the corona of the zeolite nanoparticles. Moreover, a high selective adsorption for apolipoprotein C-III (APOC-III) and fibrinogen on the zeolite nanoparticles at high plasma concentration (100%) was observed. While the zeolite nanoparticles exposed to low plasma concentration (10%) exhibited a high selective adsorption for immunoglobulin gamma (i.e. IGHG1, IGHG2 and IGHG4) proteins. The zeolite nanoparticles can potentially be used for selectively capture of APOC-III in order to reduce the activation of lipoprotein lipase inhibition during hypertriglyceridemia treatment. The zeolite nanoparticles can be adapted to hemophilic patients (hemophilia A (F-VIII deficient) and hemophilia B (F-IX deficient)) with a risk of bleeding, and thus might be potentially used in combination with the existing therapy.

Zeolite Nanoparticles for Selective Sorption of Plasma Proteins

PubMed Central

Rahimi, M.; Ng, E.-P.; Bakhtiari, K.; Vinciguerra, M.; Ahmad, H. Ali; Awala, H.; Mintova, S.; Daghighi, M.; Bakhshandeh Rostami, F.; de Vries, M.; Motazacker, M. M.; Peppelenbosch, M. P.; Mahmoudi, M.; Rezaee, F.

2015-01-01

The affinity of zeolite nanoparticles (diameter of 8–12 nm) possessing high surface area and high pore volume towards human plasma proteins has been investigated. The protein composition (corona) of zeolite nanoparticles has been shown to be more dependent on the plasma protein concentrations and the type of zeolites than zeolite nanoparticles concentration. The number of proteins present in the corona of zeolite nanoparticles at 100% plasma (in vivo state) is less than with 10% plasma exposure. This could be due to a competition between the proteins to occupy the corona of the zeolite nanoparticles. Moreover, a high selective adsorption for apolipoprotein C-III (APOC-III) and fibrinogen on the zeolite nanoparticles at high plasma concentration (100%) was observed. While the zeolite nanoparticles exposed to low plasma concentration (10%) exhibited a high selective adsorption for immunoglobulin gamma (i.e. IGHG1, IGHG2 and IGHG4) proteins. The zeolite nanoparticles can potentially be used for selectively capture of APOC-III in order to reduce the activation of lipoprotein lipase inhibition during hypertriglyceridemia treatment. The zeolite nanoparticles can be adapted to hemophilic patients (hemophilia A (F-VIII deficient) and hemophilia B (F-IX deficient)) with a risk of bleeding, and thus might be potentially used in combination with the existing therapy. PMID:26616161

A highly reversible room-temperature lithium metal battery based on crosslinked hairy nanoparticles

NASA Astrophysics Data System (ADS)

Choudhury, Snehashis; Mangal, Rahul; Agrawal, Akanksha; Archer, Lynden A.

2015-12-01

Rough electrodeposition, uncontrolled parasitic side-reactions with electrolytes and dendrite-induced short-circuits have hindered development of advanced energy storage technologies based on metallic lithium, sodium and aluminium electrodes. Solid polymer electrolytes and nanoparticle-polymer composites have shown promise as candidates to suppress lithium dendrite growth, but the challenge of simultaneously maintaining high mechanical strength and high ionic conductivity at room temperature has so far been unmet in these materials. Here we report a facile and scalable method of fabricating tough, freestanding membranes that combine the best attributes of solid polymers, nanocomposites and gel-polymer electrolytes. Hairy nanoparticles are employed as multifunctional nodes for polymer crosslinking, which produces mechanically robust membranes that are exceptionally effective in inhibiting dendrite growth in a lithium metal battery. The membranes are also reported to enable stable cycling of lithium batteries paired with conventional intercalating cathodes. Our findings appear to provide an important step towards room-temperature dendrite-free batteries.

A highly reversible room-temperature lithium metal battery based on crosslinked hairy nanoparticles.

PubMed

Choudhury, Snehashis; Mangal, Rahul; Agrawal, Akanksha; Archer, Lynden A

2015-12-04

Rough electrodeposition, uncontrolled parasitic side-reactions with electrolytes and dendrite-induced short-circuits have hindered development of advanced energy storage technologies based on metallic lithium, sodium and aluminium electrodes. Solid polymer electrolytes and nanoparticle-polymer composites have shown promise as candidates to suppress lithium dendrite growth, but the challenge of simultaneously maintaining high mechanical strength and high ionic conductivity at room temperature has so far been unmet in these materials. Here we report a facile and scalable method of fabricating tough, freestanding membranes that combine the best attributes of solid polymers, nanocomposites and gel-polymer electrolytes. Hairy nanoparticles are employed as multifunctional nodes for polymer crosslinking, which produces mechanically robust membranes that are exceptionally effective in inhibiting dendrite growth in a lithium metal battery. The membranes are also reported to enable stable cycling of lithium batteries paired with conventional intercalating cathodes. Our findings appear to provide an important step towards room-temperature dendrite-free batteries.

A highly reversible room-temperature lithium metal battery based on crosslinked hairy nanoparticles

PubMed Central

Choudhury, Snehashis; Mangal, Rahul; Agrawal, Akanksha; Archer, Lynden A.

2015-01-01

Rough electrodeposition, uncontrolled parasitic side-reactions with electrolytes and dendrite-induced short-circuits have hindered development of advanced energy storage technologies based on metallic lithium, sodium and aluminium electrodes. Solid polymer electrolytes and nanoparticle-polymer composites have shown promise as candidates to suppress lithium dendrite growth, but the challenge of simultaneously maintaining high mechanical strength and high ionic conductivity at room temperature has so far been unmet in these materials. Here we report a facile and scalable method of fabricating tough, freestanding membranes that combine the best attributes of solid polymers, nanocomposites and gel-polymer electrolytes. Hairy nanoparticles are employed as multifunctional nodes for polymer crosslinking, which produces mechanically robust membranes that are exceptionally effective in inhibiting dendrite growth in a lithium metal battery. The membranes are also reported to enable stable cycling of lithium batteries paired with conventional intercalating cathodes. Our findings appear to provide an important step towards room-temperature dendrite-free batteries. PMID:26634644

Nanoscale size effect in in situ titanium based composites with cell viability and cytocompatibility studies.

PubMed

Miklaszewski, Andrzej; Jurczyk, Mieczysława U; Kaczmarek, Mariusz; Paszel-Jaworska, Anna; Romaniuk, Aleksandra; Lipińska, Natalia; Żurawski, Jakub; Urbaniak, Paulina; Jurczyk, Mieczyslaw

2017-04-01

Novel in situ Metal Matrix Nanocomposite (MMNC) materials based on titanium and boron, revealed their new properties in the nanoscale range. In situ nanocomposites, obtained through mechanical alloying and traditional powder metallurgy compaction and sintering, show obvious differences to their microstructural analogue. A unique microstructure connected with good mechanical properties reliant on the processing conditions favour the nanoscale range of results of the Ti-TiB in situ MMNC example. The data summarised in this work, support and extend the knowledge boundaries of the nanoscale size effect that influence not only the mechanical properties but also the studies on the cell viability and cytocompatibility. Prepared in the same bulk, in situ MMNC, based on titanium and boron, could be considered as a possible candidate for dental implants and other medical applications. The observed relations and research conclusions are transferable to the in situ MMNC material group. Aside from all the discussed relations, the increasing share of these composites in the ever-growing material markets, heavily depends on the attractiveness and a possible wider application of these composites as well as their operational simplicity presented in this work. Copyright © 2016 Elsevier B.V. All rights reserved.

Ag Nanoparticles-enhanced Fluorescence of Terbium-Deferasirox Complexes for the Highly Sensitive Determination of Deferasirox.

PubMed

Abolhasani, Jafar; Naderali, Roza; Hassanzadeh, Javad

2016-01-01

We describe the effect of different sized gold and silver nanoparticles on the terbium sensitized fluorescence of deferasirox. It is indicated that silver nanostructures, especially 18 nm Ag nanoparticles (AgNPs), have a remarkable amplifying effect compared to Au nanoparticles. Based on this observation, a highly sensitive and selective method was developed for the determination of deferasirox. Effects of various parameters like AgNPs and Tb(3+) concentration and pH of media were investigated. Under the optimal conditions, a calibration curve was plotted as the fluorescence intensities versus the concentration of deferasirox in the range of 0.1 to 200 nmol L(-1), and detection limit of 0.03 nmol L(-1) was obtained. The method has good linearity, recovery, reproducibility and sensitivity, and was satisfactorily applied for the determination of deferasirox in urine and pharmaceutical samples.

[Health effects of nanoparticles and nanomaterials (II) methods for measurement of nanoparticles and their presence in the air].

PubMed

Fujitani, Yuji; Hirano, Seishiro

2008-05-01

The mass concentrations of airborne particles in the atmospheric, indoor, and industrial environments are regulated by air quality standards. Epidemiological studies show that there are significant positive correlations between particle mass concentrations and adverse health effects. In this context nanoparticles in the air, which are defined as particles with a diameter (Dp) of less than 50 nm or 100 nm for engineered ones, are gaining increasing attention despite a small contribution to the mass of total airborn particles. Contrary to the mass concentration the number concentrations of atmospheric nanoparticles are quite high in most cases. Moreover there is limited toxicological information on nanoparticles, although the deposition rate of nanoparticles in the respiratory region is known to be relatively high. Accordingly there are a lot of debates about what metric is best to depict the size distribution of nanoparticles, number, surface area, or mass. In this paper, we report methods for measurement of nanoparticles on the basis of those metrics. We also report sources of nanoparticle in the environment and occupational settings. The high number concentration of nanoparticles of 20-30 nm modal diameters have been documented at roadsides. Diesel-powered vehicles are major sources of those nanoparticles in the urban atmosphere. Engineered nanoparticles generate in some occupational settings in the handling processes such as bagging and cleaning with vacuum cleaners.

Synthesis, characterization, and magnetic properties of ZnO-ZnFe2O4 nanoparticles with high photocatalytic activity

NASA Astrophysics Data System (ADS)

Falak, P.; Hassanzadeh-Tabrizi, S. A.; Saffar-Teluri, A.

2017-11-01

In the present research, a magnetic ZnO-ZnFe2O4 binary nanocomposite was synthesized by a one-step microemulsion method. The characteristics of the synthesized powders were characterized using various analytical instruments including X-ray diffraction, scanning electron microscope, transmission electron microscope, thermogravimetric and differential thermal analysis, vibrating sample magnetometer, and ultraviolet-visible spectroscopy. The results of transmission electron microscope proved that the synthesized nanoparticles have irregular morphologies and the average particle size is about 20 nm. The photocatalytic investigation of ZnO-ZnFe2O4 nanoparticles was carried out using methylene blue solution under UV light. The synthesized nanoparticles showed enhanced photocatalytic performance in comparison with the ZnO nanoparticles more than 40%. The magnetization saturation value of ZnO-ZnFe2O4 nanoparticles was about 5.8 emu/g, which was high enough to be magnetically removed by applying a magnetic field. The results showed that the magnetization and coercivity of the samples reduced by increasing calcination temperature.

Theranostic nanoplatform based on polypyrrole nanoparticles for photoacoustic imaging and photothermal therapy

NASA Astrophysics Data System (ADS)

Liu, Hui; Li, Wenchao; Cao, Yang; Guo, Yuan; Kang, Yuejun

2018-03-01

Development of effective theranostic nanoplatforms against malignant tumor is still a challenge. With desirable near-infrared (NIR) light-responsive properties, polypyrrole nanoparticles (PPy NPs) are one of the promising theranostic candidates for cancer photoacoustic imaging and photothermal therapy. Here, PPy NPs with distinct sizes were prepared using a facile aqueous dispersion polymerization method. The formed PPy NPs are uniform in size with narrow size distribution. Characterization data show that PPy NPs with a diameter around 50 nm (P50) display stronger absorption in the NIR range compared to 40 and 60 nm PPy NPs, which further influences their photo-responsive properties. Due to their higher NIR absorption, P50 NPs have better photoacoustic imaging property and photothermal conversion ability than the other two kinds of PPy NPs. The photothermal stability of P50 NPs was proved to be excellent. The CCK-8 assays show that PPy NPs have obvious acute cytotoxicity within 6 h and desirable cytocompatibility for longer incubation time (12 and 24 h). After 6-h incubation, P50 NPs could be internalized by HeLa cells. Their photothermal tumor ablation effect was demonstrated under 808-nm laser irradiation. These findings may provide in-depth understanding of the PPy-based multifunctional nanomaterials for the development of theranostic systems against cancer.

Functionalized graphene oxide nanoparticles for cancer cell-specific delivery of antitumor drug.

PubMed

Zhao, Xubo; Yang, Liangwei; Li, Xiaorui; Jia, Xu; Liu, Lei; Zeng, Jin; Guo, Jinshan; Liu, Peng

2015-01-21

The unique reduction-triggered functional graphene oxide nanoparticles (GON) with well-defined size and uniform distribution were designed as an innovative drug delivery platform for cancer treatment for the first time, via the redox radical polymerization of methacrylic acid from the polyethylene glycol (PEG) modified GON (GON-PEG), following by cross-linking with cystamine. Thermogravimetric analysis demonstrates that the typical PMAA2-GON-PEG carriers contain about 16 wt % PEG segments and 33 wt % poly(methacrylic acid) (PMAA) brushes. PEG moieties are incorporated to make the drug delivery platforms stealthy during blood circulation. Notably, introducing the cross-linked PMAA brushes efficiently minimizes the premature release of doxorubicin (DOX) in the stimulated normal tissues, and accelerates DOX release in the stimulated tumor tissues through response to reduce agent. The carriers showed a 6-fold faster releasing rate at pH 5.0 in the presence of 10 mM glutathione (GSH) (stimulated tumor tissues) than at pH 7.4 with 10 μM GSH (stimulated normal tissues). In vitro cytotoxicity test also showed that the cross-linked PMAA2-GON-PEG (CPMAA2-GON-PEG) carriers had remarkable cytocompatibility, and that the DOX-loaded CPMAA2-GON-PEG had excellent killing capability to SiHa cells.

Nickel nanoparticle decorated graphene for highly selective isolation of polyhistidine-tagged proteins

NASA Astrophysics Data System (ADS)

Liu, Jia-Wei; Yang, Ting; Ma, Lin-Yu; Chen, Xu-Wei; Wang, Jian-Hua

2013-12-01

Nickel nanoparticle decorated graphene (GP-Ni) is prepared by one-pot hydrothermal reduction of graphene oxide and nickel cations by hydrazine hydrate in the presence of poly(sodium-p-styrenesulfonate) (PSS). The GP-Ni hybrid is characterized by XRD, TEM, SEM, XPS, Raman and FT-IR spectra, demonstrating the formation of poly-dispersed nickel nanoparticles with an average size of 83 nm attached on the surface of graphene sheets. The GP-Ni hybrid exhibits ferromagnetic behavior with a magnetization saturation of 31.1 emu g-1 at 10 000 Oersted (Oe). The GP-Ni also possesses favorable stability in aqueous medium and rapid magnetic response to an external magnetic field. These make it a novel magnetic adsorbent for the separation/isolation of His6-tagged recombinant proteins from a complex sample matrix (cell lysate). The targeted protein species is captured onto the surface of the GP-Ni hybrid via specific metal affinity force between polyhistidine groups and nickel nanoparticles. The SDS-PAGE assay indicates highly selective separation of His6-tagged Smt A from cell lysate. The GP-Ni hybrid displays favorable performance on the separation/isolation of His6-tagged recombinant proteins with respect to the commercial NTA-Ni2+ column.

Fabrication of highly hydrophobic two-component thermosetting polyurethane surfaces with silica nanoparticles

NASA Astrophysics Data System (ADS)

Yang, Guang; Song, Jialu; Hou, Xianghui

2018-05-01

Highly hydrophobic thermosetting polyurethane (TSU) surfaces with micro-nano hierarchical structures were developed by a simple process combined with sandpaper templates and nano-silica embellishment. Sandpapers with grit sizes varying from 240 to 7000 grit were used to obtain micro-scale roughness on an intrinsic hydrophilic TSU surface. The surface wettability was investigated by contact angle measurement. It was found that the largest contact angle of the TSU surface without nanoparticles at 102 ± 3° was obtained when the template was 240-grit sandpaper and the molding progress started after 45 min curing of TSU. Silica nanoparticles modified with polydimethylsiloxane were scattered onto the surfaces of both the polymer and the template to construct the desirable nanostructures. The influences of the morphology, surface composition and the silica content on the TSU surface wettability were studied by scanning electron microscopy (SEM), attenuated total reflection (ATR) infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The surface of the TSU/SiO2 nanocomposites containing 4 wt% silica nanoparticles exhibited a distinctive dual-scale structure and excellent hydrophobicity with the contact angle above 150°. The mechanism of wettability was also discussed by Wenzel model and Cassie-Baxter model.

High-performance antibacterial of montmorillonite decorated with silver nanoparticles using microwave-assisted method

NASA Astrophysics Data System (ADS)

Kheiralla, Zeinab Mohamed Hassan; Rushdy, Abeer Ahmed; Betiha, Mohamed Ahmed; Yakob, Naglaa Abdullah Nasif

2014-08-01

Syntheses of silver nanocomposites (AgNPs@MMT) were fabricated with different silver nanoparticles to montmorillonite clay (MMT) ratios using microwave-assisted synthesis method, and silver nitrate was used as the precursor of silver nanoparticles. The antibacterial activities of the nanocomposite were evaluated against Staphylococcus aureus and Pseudomonas aeruginosa bacteria by the disk diffusion and macrodilution broth techniques. The prepared nanocomposites were characterized by N2 adsorption-desorption isotherms, X-ray diffraction (XRD), field emission scanning electron microscope, high-resolution transmission electron microscope (HRTEM), X-ray fluorescence spectroscopy and Fourier transform infrared spectroscopy. The wide-angle XRD patterns and HRTEM images demonstrate that silver nanoparticles were fabricated on surface and within MMT channels. The diameters of the AgNPs were below 15 nm, as indicated by UV-Vis absorption, which effectively controlled by the pores of the MMT host. Data revealed that 5 % AgNP@MMT nanocomposite is much more effective than silver nitrate and shows strong antibacterial activities. The efficiency of antibiotics increased when combined with 5 % AgNP@MMT nanocomposite against both the tested strains. The increase in fold area was higher in case of P. aeruginosa than S. aureus. The highest percentage of fold increases was found for Sulfamethaxole/Trimethoprim and Oxacillin followed by Levofloxaci and Nalidixic acid against P.aeruginosa. On the other hand, Imipenem increases activity in presence of AgNP@MMT nanocomposite against S. aureus. Overall, the synergistic effect of antibiotics and nanoparticles clearly revealed that nanoparticles can be effectively used in combination with antibiotics in order to improve their efficiency against various pathogenic microbes. The suspensions of the synthesized nanocomposites were found to be stable over a long time without any sign of detachment of AgNPs.

Oxygen plasma surface modification augments poly(L-lactide-co-glycolide) cytocompatibility toward osteoblasts and minimizes immune activation of macrophages.

PubMed

Scislowska-Czarnecka, Anna; Szmigiel, Dariusz; Genet, Michel; Dupont-Gillain, Christine; Pamula, Elzbieta; Kolaczkowska, Elzbieta

2015-12-01

Here, we report on modification of one of the model biomedical polymers, poly L-lactide-co-glycolide (PLGA; 85:15), by reactive ion etching (RIE) oxygen plasma treatment. PLGA's major disadvantage is high hydrophobicity which restrains binding of cell-adhesive proteins and host cells. In the current approach, we aimed to answer two questions: (1) will only short (10 s) and moderate (20-200 mTorr, 45-90 W) RIE oxygen plasma treatment, leading to decrease of water contact angle by only up to 10°, sufficiently improve PLGA adherence to cells, and (2) how will this affect osteoblasts and activation of the immune system? All obtained modified PLGAs had improved hydrophilicity but unaltered roughness (as revealed by water contact angle measurements, X-ray photoelectron spectroscopy, and atomic force microscopy) resulting in significantly improved adhesion of osteoblasts (MG-63) and their low activation. Importantly, macrophages (RAW 264.7), one of the key cells initiating inflammation and bone resorption, responded significantly less vigorously to the modified polymers, expressing/releasing lower amounts of nitric oxide, matrix metalloproteinases (MMP-9), and pro-inflammatory cytokines (TNF-α, IL-6, IL-12p70, IFN-γ, IL-10). We conclude that already slight RIE oxygen plasma modification of PLGA is sufficient to improve its surface properties, and enhance cytocompatibility. Most importantly, this type of modification prevents excessive immune response. © 2015 Wiley Periodicals, Inc.

The effects of bacteria-nanoparticles interface on the antibacterial activity of green synthesized silver nanoparticles.

PubMed

Ahmad, Aftab; Wei, Yun; Syed, Fatima; Tahir, Kamran; Rehman, Aziz Ur; Khan, Arifullah; Ullah, Sadeeq; Yuan, Qipeng

2017-01-01

Neutralization of bacterial cell surface potential using nanoscale materials is an effective strategy to alter membrane permeability, cytoplasmic leakage, and ultimate cell death. In the present study, an attempt was made to prepare biogenic silver nanoparticles using biomolecules from the aqueous rhizome extract of Coptis Chinensis. The biosynthesized silver nanoparticles were surface modified with chitosan biopolymer. The prepared silver nanoparticles and chitosan modified silver nanoparticles were cubic crystalline structures (XRD) with an average particle size of 15 and 20 nm respectively (TEM, DLS). The biosynthesized silver nanoparticles were surface stabilized by polyphenolic compounds (FTIR). Coptis Chinensis mediated silver nanoparticles displayed significant activity against E. coli and Bacillus subtilus with a zone of inhibition 12 ± 1.2 (MIC = 25 μg/mL) and 18 ± 1.6 mm (MIC = 12.50 μg/mL) respectively. The bactericidal efficacy of these nanoparticles was considerably increased upon surface modification with chitosan biopolymer. The chitosan modified biogenic silver nanoparticles exhibited promising activity against E. coli (MIC = 6.25 μg/mL) and Bacillus subtilus (MIC = 12.50 μg/mL). Our results indicated that the chitosan modified silver nanoparticles were promising agents in damaging bacterial membrane potential and induction of high level of intracellular reactive oxygen species (ROS). In addition, these nanoparticles were observed to induce the release of the high level of cytoplasmic materials especially protein and nucleic acids into the media. All these findings suggest that the chitosan functionalized silver nanoparticles are efficient agents in disrupting bacterial membrane and induction of ROS leading to cytoplasmic leakage and cell death. These findings further conclude that the bacterial-nanoparticles surface potential modulation is an effective strategy in enhancing the antibacterial potency of silver nanoparticles

High-performance liquid chromatography separation of unsaturated organic compounds by a monolithic silica column embedded with silver nanoparticles.

PubMed

Zhu, Yang; Morisato, Kei; Hasegawa, George; Moitra, Nirmalya; Kiyomura, Tsutomu; Kurata, Hiroki; Kanamori, Kazuyoshi; Nakanishi, Kazuki

2015-08-01

The optimization of a porous structure to ensure good separation performances is always a significant issue in high-performance liquid chromatography column design. Recently we reported the homogeneous embedment of Ag nanoparticles in periodic mesoporous silica monolith and the application of such Ag nanoparticles embedded silica monolith for the high-performance liquid chromatography separation of polyaromatic hydrocarbons. However, the separation performance remains to be improved and the retention mechanism as compared with the Ag ion high-performance liquid chromatography technique still needs to be clarified. In this research, Ag nanoparticles were introduced into a macro/mesoporous silica monolith with optimized pore parameters for high-performance liquid chromatography separations. Baseline separation of benzene, naphthalene, anthracene, and pyrene was achieved with the theoretical plate number for analyte naphthalene as 36,000 m(-1). Its separation function was further extended to cis/trans isomers of aromatic compounds where cis/trans stilbenes were chosen as a benchmark. Good separation of cis/trans-stilbene with separation factor as 7 and theoretical plate number as 76,000 m(-1) for cis-stilbene was obtained. The trans isomer, however, is retained more strongly, which contradicts the long- established retention rule of Ag ion chromatography. Such behavior of Ag nanoparticles embedded in a silica column can be attributed to the differences in the molecular geometric configuration of cis/trans stilbenes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Friction mechanism of individual multilayered nanoparticles.

PubMed

Tevet, Ofer; Von-Huth, Palle; Popovitz-Biro, Ronit; Rosentsveig, Rita; Wagner, H Daniel; Tenne, Reshef

2011-12-13

Inorganic nanoparticles of layered [two-dimensional (2D)] compounds with hollow polyhedral structure, known as fullerene-like nanoparticles (IF), were found to have excellent lubricating properties. This behavior can be explained by superposition of three main mechanisms: rolling, sliding, and exfoliation-material transfer (third body). In order to elucidate the tribological mechanism of individual nanoparticles in different regimes, in situ axial nanocompression and shearing forces were applied to individual nanoparticles using a high resolution scanning electron microscope. Gold nanoparticles deposited onto the IF nanoparticles surface served as markers, delineating the motion of individual IF nanoparticle. It can be concluded from these experiments that rolling is an important lubrication mechanism for IF-WS(2) in the relatively low range of normal stress (0.96 ± 0.38 GPa). Sliding is shown to be relevant under slightly higher normal stress, where the spacing between the two mating surfaces does not permit free rolling of the nanoparticles. Exfoliation of the IF nanoparticles becomes the dominant mechanism at the high end of normal stress; above 1.2 GPa and (slow) shear; i.e., boundary lubrication conditions. It is argued that the modus operandi of the nanoparticles depends on their degree of crystallinity (defects); sizes; shape, and their mechanical characteristics. This study suggests that the rolling mechanism, which leads to low friction and wear, could be attained by improving the sphericity of the IF nanoparticle, the dispersion (deagglomeration) of the nanoparticles, and the smoothness of the mating surfaces.

Friction mechanism of individual multilayered nanoparticles

PubMed Central

Tevet, Ofer; Von-Huth, Palle; Popovitz-Biro, Ronit; Rosentsveig, Rita; Wagner, H. Daniel; Tenne, Reshef

2011-01-01

Inorganic nanoparticles of layered [two-dimensional (2D)] compounds with hollow polyhedral structure, known as fullerene-like nanoparticles (IF), were found to have excellent lubricating properties. This behavior can be explained by superposition of three main mechanisms: rolling, sliding, and exfoliation-material transfer (third body). In order to elucidate the tribological mechanism of individual nanoparticles in different regimes, in situ axial nanocompression and shearing forces were applied to individual nanoparticles using a high resolution scanning electron microscope. Gold nanoparticles deposited onto the IF nanoparticles surface served as markers, delineating the motion of individual IF nanoparticle. It can be concluded from these experiments that rolling is an important lubrication mechanism for IF-WS2 in the relatively low range of normal stress (0.96±0.38 GPa). Sliding is shown to be relevant under slightly higher normal stress, where the spacing between the two mating surfaces does not permit free rolling of the nanoparticles. Exfoliation of the IF nanoparticles becomes the dominant mechanism at the high end of normal stress; above 1.2 GPa and (slow) shear; i.e., boundary lubrication conditions. It is argued that the modus operandi of the nanoparticles depends on their degree of crystallinity (defects); sizes; shape, and their mechanical characteristics. This study suggests that the rolling mechanism, which leads to low friction and wear, could be attained by improving the sphericity of the IF nanoparticle, the dispersion (deagglomeration) of the nanoparticles, and the smoothness of the mating surfaces. PMID:22084073

A novel on-line gold nanoparticle-catalyzed luminol chemiluminescence detector for high-performance liquid chromatography.

PubMed

Zhang, Qun Lin; Wu, Liang; Lv, Chen; Zhang, Xiao Yue

2012-06-15

A novel on-line gold nanoparticle-catalyzed luminol-H(2)O(2) chemiluminescence (CL) detector for high-performance liquid chromatography (HPLC) was established, in which gold nanoparticles were produced by the on-line reaction of H(2)O(2), NaHCO(3)-Na(2)CO(3) (buffer solution of luminol), and HAuCl(4). Eight phenolic compounds (gallic acid, protocatechuic acid, protocatechuic aldehyde, 2,5-dihydroxybenzoic acid, caffeic acid, 2,3-dihydroxybenzoic acid, (+)-catechin, and (-)-epicatechin) were chosen as the model compounds. Every separated phenolic compound in the column eluent strongly enhanced the CL signal of on-line gold nanoparticle-catalyzed luminol system. The CL and UV-visible absorption spectra and transmission electron microscopy studies were carried out, and the CL enhancement mechanism was ascribed to that the presence of phenolic compound promoted the on-line formation of 38-nm-diameter gold nanoparticles, which better catalyzed the luminol-H(2)O(2) CL reaction. The effects of methanol and phosphoric acid in the proposed HPLC configuration were performed by two gradient elution programs, and the baseline profile revealed that on-line gold nanoparticle-catalyzed luminol-H(2)O(2) CL detector had better compatibility than 38 nm gold colloids-luminol-H(2)O(2) CL detector. The proposed CL detector exhibits excellent analytical performance with the low detection limit (S/N=3) of 0.53-0.97 ng/mL (10.6-19.4 pg) phenolic compounds, and offers a new strategy for developing on-line nanoparticle-catalyzed CL detector for HPLC with sensitive analysis. Copyright © 2012 Elsevier B.V. All rights reserved.

One-pot synthesis of CoNiO2 single-crystalline nanoparticles as high-performance electrode materials of asymmetric supercapacitors

NASA Astrophysics Data System (ADS)

Du, Weimin; Gao, Yanping; Tian, Qingqing; Li, Dan; Zhang, Zhenhu; Guo, Jiaojiao; Qian, Xuefeng

2015-09-01

A facile one-pot solvothermal method has been developed to synthesize CoNiO2 single-crystalline nanoparticles. Crystal phase, morphology, crystal lattice, and composition of the obtained products were characterized by X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, and energy-dispersive X-ray analysis, respectively. Results revealed that the as-synthesized CoNiO2 nanoparticles belong to cubic structure with narrow size-distribution (8-10 nm). Subsequently, new asymmetric supercapacitors were successfully assembled with CoNiO2 nanoparticles as positive electrode and activated carbon as negative electrode. The electrochemical results show that asymmetric supercapacitors based on CoNiO2 nanoparticles possess excellent supercapacitor properties, i.e., a stable electrochemical window of 0-1.7 V, higher energy density of 24.0 Wh/kg at a power density of 415.4 W/kg, and excellent cycling stability (96.8 % capacitance retention after 5000 charge-discharge cycles). Meanwhile, both a light-emitting diode and a mini fan can be powered by two series connection asymmetric supercapacitors. These results imply that the present asymmetric supercapacitors based on CoNiO2 nanoparticles possess the promising potential application in the field of high-performance energy storage.

Non-Engineered Nanoparticles of C60

PubMed Central

Deguchi, Shigeru; Mukai, Sada-atsu; Sakaguchi, Hide; Nonomura, Yoshimune

2013-01-01

We discovered that rubbing bulk solids of C60 between fingertips generates nanoparticles including the ones smaller than 20 nm. Considering the difficulties usually associated with nanoparticle production by pulverisation, formation of nanoparticles by such a mundane method is unprecedented and noteworthy. We also found that nanoparticles of C60 could be generated from bulk solids incidentally without deliberate engineering of any sort. Our findings imply that there exist highly unusual human exposure routes to nanoparticles of C60, and elucidating formation mechanisms of nanoparticles is crucial in assessing their environmental impacts. PMID:23807024

Highly nonlinear sub-micron silicon nitride trench waveguide coated with gold nanoparticles

NASA Astrophysics Data System (ADS)

Huang, Yuewang; Zhao, Qiancheng; Sharac, Nicholas; Ragan, Regina; Boyraz, Ozdal

2015-05-01

We demonstrate the fabrication of a highly nonlinear sub-micron silicon nitride trench waveguide coated with gold nanoparticles for plasmonic enhancement. The average enhancement effect is evaluated by measuring the spectral broadening effect caused by self-phase-modulation. The nonlinear refractive index n2 was measured to be 7.0917×10-19 m2/W for a waveguide whose Wopen is 5 μm. Several waveguides at different locations on one wafer were measured in order to take the randomness of the nanoparticle distribution into consideration. The largest enhancement is measured to be as high as 10 times. Fabrication of this waveguide started with a MEMS grade photomask. By using conventional optical lithography, the wide linewidth was transferred to a <100> wafer. Then the wafer was etched anisotropically by potassium hydroxide (KOH) to engrave trapezoidal trenches with an angle of 54.7º. Side wall roughness was mitigated by KOH etching and thermal oxidation that was used to generate a buffer layer for silicon nitride waveguide. The guiding material silicon nitride was then deposited by low pressure chemical vapor deposition. The waveguide was then patterned with a chemical template, with 20 nm gold particles being chemically attached to the functionalized poly(methyl methacrylate) domains. Since the particles attached only to the PMMA domains, they were confined to localized regions, therefore forcing the nanoparticles into clusters of various numbers and geometries. Experiments reveal that the waveguide has negligible nonlinear absorption loss, and its nonlinear refractive index can be greatly enhanced by gold nano clusters. The silicon nitride trench waveguide has large nonlinear refractive index, rendering itself promising for nonlinear applications.

Strengthening Aluminum Alloys for High Temperature Applications Using Nanoparticles of Al203 and Al3-X Compounds (X= Ti, V, Zr)

NASA Technical Reports Server (NTRS)

Lee, Jonathan A.

2007-01-01

In this paper the effect of nanoparticles A12O3 and A13-X compounds (X= Ti, V, Zr) on the improvement of mechanical properties of aluminum alloys for elevated temperature applications is presented. These nanoparticles were selected based on their chemical stability and low diffusions rates in aluminum matrix at high temperatures. The strengthening mechanism for aluminum alloy is based on the mechanical blocking of dislocation movements by these nanoparticles. Samples were prepared from A12O3 nanoparticle preforms, which were produced using ceramic injection molding process and pressure infiltrated by molten aluminum. A12O3 nanoparticles can also be homogeneously mixed with aluminum powder and consolidated into samples through hot pressing and sintering. On the other hand, the Al3-X nanoparticles are produced as precipitates via in situ reactions with molten aluminum alloys using conventional casting techniques. The degree of alloy strengthening using nanoparticles will depend on the materials, particle size, shape, volume fraction, and mean inter-particle spacing.

A simple high-yield synthesis of high-purity Hägg carbide (χ-Fe5C2) nanoparticles with extraordinary electrochemical properties.

PubMed

Malina, Ondřej; Jakubec, Petr; Kašlík, Josef; Tuček, Jiří; Zbořil, Radek

2017-07-27

Iron carbides are of eminent interest in both fundamental scientific research and in the industry owing to their properties such as excellent mechanical strength and chemical inertness. They have been found very effective in Fischer-Tropsch synthesis exploring heterogeneous catalysis for the production of chemicals such as liquid fuel and they have also been employed as successful promoters for the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). However, so far there have been only a few reports on the application of iron carbide nanoparticles in the field of electrochemical sensing. Here, we present a stable form of Hägg carbide nanoparticles synthesized from a rare form of iron(iii) oxide (β-Fe 2 O 3 ). The as-prepared nanomaterial was characterized employing X-ray powder diffraction and Mössbauer spectroscopy to prove its composition as well as an extraordinary high purity level. It turned out that Hägg carbide nanoparticles prepared by thermally treated β-Fe 2 O 3 exhibited excellent electrochemical properties including low charge transfer resistivity (R ct ) compared to the other tested materials. Moreover, the Hägg carbide nanoparticles were tested as a promising electrocatalyst for voltammetric detection of the antibiotic metronidazole proving its practical applicability.

High performance hybrid silicon micropillar solar cell based on light trapping characteristics of Cu nanoparticles

NASA Astrophysics Data System (ADS)

Zhang, Yulong; Fan, Zhiqiang; Zhang, Weijia; Ma, Qiang; Jiang, Zhaoyi; Ma, Denghao

2018-05-01

High performance silicon combined structure (micropillar with Cu nanoparticles) solar cell has been synthesized from N-type silicon substrates based on the micropillar array. The combined structure solar cell exhibited higher short circuit current rather than the silicon miropillar solar cell, which the parameters of micropillar array are the same. Due to the Cu nanoparticles were decorated on the surface of silicon micropillar array, the photovoltaic properties of cells have been improved. In addition, the optimal efficiency of 11.5% was measured for the combined structure solar cell, which is better than the silicon micropillar cell.

The effect of high-power plasma flows on tungsten plates with multilayer films of tungsten nanoparticles

NASA Astrophysics Data System (ADS)

Gorokhov, M. V.; Kozhevin, V. M.; Yavsin, D. A.; Voronin, A. V.; Gurevich, S. A.

2017-04-01

We have experimentally studied the action of high-power plasma flows on pure tungsten plates covered with multilayer films of tungsten nanoparticles formed by the method of laser electrodeposition. The samples were irradiated using a plasma gun producing hydrogen (helium) plasma flows with power density up to 35 GW/cm2. The resulting surface morphology was studied by scanning electron microscopy (SEM). SEM data showed that tungsten plates coated by nanoparticles are more resistant to the formation of microcracks than are pure tungsten plates.

Facile, one-pot synthesis, and antibacterial activity of mesoporous silica nanoparticles decorated with well-dispersed silver nanoparticles.

PubMed

Tian, Yue; Qi, Juanjuan; Zhang, Wei; Cai, Qiang; Jiang, Xingyu

2014-08-13

In this study, we exploit a facile, one-pot method to prepare MCM-41 type mesoporous silica nanoparticles decorated with silver nanoparticles (Ag-MSNs). Silver nanoparticles with diameter of 2-10 nm are highly dispersed in the framework of mesoporous silica nanoparticles. These Ag-MSNs possess an enhanced antibacterial effect against both Gram-positive and Gram-negative bacteria by preventing the aggregation of silver nanoparticles and continuously releasing silver ions for one month. The cytotoxicity assay indicates that the effective antibacterial concentration of Ag-MSNs shows little effect on human cells. This report describes an efficient and economical route to synthesize mesoporous silica nanoparticles with uniform silver nanoparticles, and these nanoparticles show promising applications as antibiotics.

Modular Carbon and Gold Nanoparticles for High Field MR Imaging and Theranostics

NASA Astrophysics Data System (ADS)

Rammohan, Nikhil

The ability to track labeled cancer cells in vivo would allow researchers to study their distribution, growth and metastatic potential within the intact organism. Magnetic Resonance (MR) imaging is invaluable for tracking cancer cells in vivo as it benefits from high spatial resolution and absence of ionizing radiation. However, many MR contrast agents (CAs) required to label cells either do not significantly accumulate in cells or are not biologically compatible for translational studies. Accordingly, we have developed carbon- and gold-nanoparticles coupled to gadolinium(III) [Gd(III)] chelates for T1-weighted MR imaging that demonstrated remarkable properties for cell tracking in vitro and in vivo.. We created nanodiamond-Gd(III) aggregates (NDG) by peptide coupling Gd(III) chelates to aminated nanodiamonds. NDG had high relaxivity independent of field strength (unprecedented for Gd(III)-nanoparticle conjugates), and demonstrated a 300-fold increase in cellular delivery of Gd(III) compared to clinical Gd(III) chelates. Further, we were able to monitor the tumor growth of NDG-labeled flank tumors by T1-weighted MRI for 26 days in vivo, longer than reported for other MR CAs or nuclear agents. Further, theranostic nanodiamond-gadolinium(III)-doxorubicin (ND-Gd-Dox) aggregates were generated by conjugating doxorubicin (ND-Gd-Dox), which enabled efficient cancer chemotherapy in breast cancer cells. Further, we synthesized Gd(III)-gold nanoconjugates (Gd AuNPs) with varied chelate structure and nanoparticle-chelate linker length. Significantly enhanced cell labeling was demonstrated compared to previous gadolinium-gold-DNA nanoconstructs. Differences in Gd(III) loading, surface packing and cell uptake were observed between four different Gd AuNP formulations suggesting that linker length and surface charge play an important role in cell labeling. The best performing Gd AuNPs afforded 23.6 +/- 3.6 fmol of Gd(III) per cell at an incubation concentration of 27.5 micro

Supraparamagnetic, conductive, and processable multifunctional graphene nanosheets coated with high-density Fe3O4 nanoparticles.

PubMed

He, Hongkun; Gao, Chao

2010-11-01

The amazing properties of graphene are triggering extensive interests of both scientists and engineers, whereas how to fully utilize the unique attributes of graphene to construct novel graphene-based composites with tailor-made, integrated functions remains to be a challenge. Here, we report a facile approach to multifunctional iron oxide nanoparticle-attached graphene nanosheets (graphene@Fe(3)O(4)) which show the integrated properties of strong supraparamagnetism, electrical conductivity, highly chemical reactivity, good solubility, and excellent processability. The synthesis method is efficient, scalable, green, and controllable and has the feature of reduction of graphene oxide and formation of Fe(3)O(4) nanoparticles in one step. When the feed ratios are adjusted, the average diameter of Fe(3)O(4) nanoparticles (1.2-6.3 nm), the coverage density of Fe(3)O(4) nanoparticles on graphene nanosheets (5.3-57.9%), and the saturated magnetization of graphene@Fe(3)O(4) (0.5-44.1 emu/g) can be controlled readily. Because of the good solubility of the as-prepared graphene@Fe(3)O(4), highly flexible and multifunctional films composed of polyurethane and a high content of graphene@Fe(3)O(4) (up to 60 wt %) were fabricated by the solution-processing technique. The graphene@Fe(3)O(4) hybrid sheets showed electrical conductivity of 0.7 S/m and can be aligned into a layered-stacking pattern in an external magnetic field. The versatile graphene@Fe(3)O(4) nanosheets hold great promise in a wide range of fields, including magnetic resonance imaging, electromagnetic interference shielding, microwave absorbing, and so forth.

Terahertz cascades from nanoparticles

NASA Astrophysics Data System (ADS)

Arnardottir, K. B.; Liew, T. C. H.

2018-05-01

In this article we propose a system capable of terahertz (THz) radiation with quantum yield above unity. The system consists of nanoparticles where the material composition varies along the radial direction of each nanoparticle in such a way that a ladder of equidistant energy levels emerges. By then exciting the highest level of this ladder we produce multiple photons of the same frequency in the THz range. We demonstrate how we can calculate a continuous material composition profile that achieves a high quantum yield and then show that a more experimentally friendly design of a multishell nanoparticle can still result in a high quantum yield.

Seed mediated synthesis of highly mono-dispersed gold nanoparticles in the presence of hydroquinone

NASA Astrophysics Data System (ADS)

Kumar, Dhiraj; Mutreja, Isha; Sykes, Peter

2016-09-01

Gold nanoparticles (AuNPs) are being studied for several biomedical applications, including drug delivery, biomedical imaging, contrast agents and tumor targeting. The synthesis of nanoparticles with a narrow size distribution is critical for these applications. We report the synthesis of highly mono-dispersed AuNPs by a seed mediated approach, in the presence of tri-sodium citrate and hydroquinone (HQ). AuNPs with an average size of 18 nm were used for the synthesis of highly mono-dispersed nanocrystals of an average size 40 nm, 60 nm, 80 nm and ˜100 nm; but the protocol is not limited to these sizes. The colloidal gold was subjected to UV-vis absorbance spectroscopy, showing a red shift in lambda max wavelength, peaks at 518.47 nm, 526.37 nm, 535.73 nm, 546.03 nm and 556.50 nm for AuNPs seed (18 nm), 40 nm, 60 nm, 80 nm and ˜100 nm respectively. The analysis was consistent with dynamic light scattering and electron microscopy. Hydrodynamic diameters measured were 17.6 nm, 40.8 nm, 59.8 nm, 74.1 nm, and 91.4 nm (size by dynamic light scattering—volume %); with an average poly dispersity index value of 0.088, suggesting mono-dispersity in the size distribution, which was also confirmed by transmission electron microscopy analysis. The advantage of a seed mediated approach is a multi-step growth of nanoparticle size that enables us to control the number of nanoparticles in the suspension, for size ranging from 24.5 nm to 95.8 nm. In addition, the HQ-based synthesis of colloidal nanocrystals allowed control of the particle size and size distribution by tailoring either the number of seeds, amount of gold precursor or reducing agent (HQ) in the final reaction mixture.

Carbon materials-functionalized tin dioxide nanoparticles toward robust, high-performance nitrogen dioxide gas sensor.

PubMed

Zhang, Rui; Liu, Xiupeng; Zhou, Tingting; Wang, Lili; Zhang, Tong

2018-08-15

Carbon (C) materials, which process excellent electrical conductivity and high carrier mobility, are promising sensing materials as active units for gas sensors. However, structural agglomeration caused by chemical processes results in a small resistance change and low sensing response. To address the above issues, structure-derived carbon-coated tin dioxide (SnO 2 ) nanoparticles having distinct core-shell morphology with a 3D net-like structure and highly uniform size are prepared by careful synthesis and fine structural design. The optimum carbon-coated SnO 2 nanoparticles (SnO 2 /C)-based gas sensor exhibits a low working temperature, excellent selectivity and fast response-recovery properties. In addition, the SnO 2 /C-based gas sensor can maintain a sensitivity to nitrogen dioxide (NO 2 ) of 3 after being cycled 4 times at 140 °C for, suggesting its good long-term stability. The structural integrity, good synergistic properties, and high gas-sensing performance of SnO 2 /C render it a promising sensing material for advanced gas sensors. Copyright © 2018 Elsevier Inc. All rights reserved.

Industrial applications of nanoparticles.

PubMed

Stark, W J; Stoessel, P R; Wohlleben, W; Hafner, A

2015-08-21

Research efforts in the past two decades have resulted in thousands of potential application areas for nanoparticles - which materials have become industrially relevant? Where are sustainable applications of nanoparticles replacing traditional processing and materials? This tutorial review starts with a brief analysis on what makes nanoparticles attractive to chemical product design. The article highlights established industrial applications of nanoparticles and then moves to rapidly emerging applications in the chemical industry and discusses future research directions. Contributions from large companies, academia and high-tech start-ups are used to elucidate where academic nanoparticle research has revolutionized industry practice. A nanomaterial-focused analysis discusses new trends, such as particles with an identity, and the influence of modern instrument advances in the development of novel industrial products.

The nano-particle dispersion strengthening of V-4Cr-4Ti alloys for high temperature application in fusion reactors

NASA Astrophysics Data System (ADS)

Zheng, Pengfei; Chen, Jiming; Xu, Zengyu; Duan, Xuru

2013-10-01

V-4Cr-4Ti was identified as an attractive structural material for Li blanket in fusion reactors. However, both high temperature and irradiation induced degradation are great challenges for this material. It was thought that the nano-particles with high thermal stability can efficiently strengthen the alloy at elevated temperatures, and accommodate the irradiation induced defects at the boundaries. This study is a starting work aiming at improving the creep resistance and reducing the irradiation induced degradation for V-4Cr-4Ti alloy. Currently, we focus on the preparation of some comparative nano-particle dispersion strengthened V-4Cr-4Ti alloys. A mechanical alloying (MA) route is used to fabricate yttrium and carbides added V-4Cr-4Ti alloys. Nano-scale yttria, carbides and other possible particles have a combined dispersion-strengthening effect on the matrices of these MA-fabricated V-4Cr-4Ti alloys. High-temperature annealing is carried out to stabilize the optimized nano-particles. Mechanical properties are tested. Microstructures of the MA-fabricated V-4Cr-4Ti alloys with yttrium and carbide additions are characterized. Based on these results, the thermal stability of different nano-particle agents are classified. ITER related China domestic project 2011GB108007.

High refractive index gold nanoparticle doped Bi2O3-B2O3 glasses for THz frequencies

NASA Astrophysics Data System (ADS)

Singla, Shivani; Achanta, Venu Gopal; Mahendru, Nancy; Prabhu, Shriganesh S.; Falconieri, Mauro; Sharma, Gopi

2017-10-01

Direct incorporation of gold nanoparticles from suspensions in 30%Bi2O3:70%B2O3 glass was achieved. This method has advantage over traditional methods where a gold salt is added to the precursor mixture and gold nanoparticles are obtained with subsequent heat treatment, eventually inducing crystallization with associated scattering of light and hence resulting in reduced optical quality of material. X-ray diffraction and differential thermal analysis were carried out in order to confirm the amorphous nature of the material and thermal properties of the prepared glasses, respectively. The size of the gold nanoparticles in the prepared glass matrix was measured using scanning electron microscopy. Optical characterization of prepared glass samples in ultraviolet-visible and terahertz regions was performed using ellipsometry, UV-VIS spectrophotometry and THz-time-domain spectroscopy. Comparison was made between glasses with and without gold nanoparticles and the effect of gold nanoparticle concentration on their optical behaviour is studied. These glasses are found to have high refractive index in the THz region making them suitable for photonic applications.

Ultra-high sensitive substrates for surface enhanced Raman scattering, made of 3 nm gold nanoparticles embedded on SiO2 nanospheres

NASA Astrophysics Data System (ADS)

Phatangare, A. B.; Dhole, S. D.; Dahiwale, S. S.; Bhoraskar, V. N.

2018-05-01

The surface properties of substrates made of 3 nm gold nanoparticles embedded on SiO2 nanospheres enabled fingerprint detection of thiabendazole (TBZ), crystal violet (CV) and 4-Aminothiophenol (4-ATP) at an ultralow concentration of ∼10-18 M by surface enhanced Raman spectroscopy (SERS). Gold nanoparticles of an average size of ∼3 nm were synthesized and simultaneously embedded on SiO2 nanospheres by the electron irradiation method. The substrates made from the 3 nm gold nanoparticles embedded on SiO2 nanospheres were successfully used for recording fingerprint SERS spectra of TBZ, CV and 4-ATP over a wide range of concentrations from 10-6 M to 10-18 M using 785 nm laser. The unique features of these substrates are roughness near the surface due to the inherent structural defects of 3 nm gold nanoparticles, nanogaps of ≤ 1 nm between the embedded nanoparticles and their high number. These produced an abundance of nanocavities which act as active centers of hot-spots and provided a high electric field at the reporter molecules and thus an enhancement factor required to record the SERS spectra at ultra low concentration of 10-18 M. The SERS spectra recorded by the substrates of 4 nm and 6 nm gold nanoparticles are discussed.

A high performance quasi-solid-state supercapacitor based on CuMnO2 nanoparticles

NASA Astrophysics Data System (ADS)

Wang, Lu; Arif, Muhammad; Duan, Guorong; Chen, Shenming; Liu, Xiaoheng

2017-07-01

Mixed metal or transition metal oxides hold an unveiled potential as one of the most promising energy storage material because of their excellent stability, reliable conductivity, and convenient use. In this work, CuMnO2 nanoparticles are successfully prepared by a facile hydrothermal process with the help of dispersing agent cetyltrimethylammonium bromide (CTAB). CuMnO2 nanoparticles possess a uniform quadrilateral shape, small size (approximately 25 × 25 nm-35 × 35 nm), excellent dispersity, and large specific surface specific (56.9 m2 g-1) with an interparticle mesoporous structure. All these characteristics can bring benefit for their application in supercapacitor. A quasi-solid-state symmetric supercapacitor device is assembled by using CuMnO2 nanoparticles as both positive electrode and negative electrode. The device exhibits good supercapacitive performance with a high specific capacitance (272 F g-1), a maximum power density of 7.56 kW kg-1 and a superior cycling stability of 18,000 continuous cycles, indicating an excellent potential to be used in energy storage device.

Antifungal activity of gold nanoparticles prepared by solvothermal method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmad, Tokeer, E-mail: tahmad3@jmi.ac.in; Wani, Irshad A.; Lone, Irfan H.

2013-01-15

Graphical abstract: Gold nanoparticles (7 and 15 nm) of very high surface area (329 and 269 m{sup 2}/g) have been successfully synthesized through solvothermal method by using tin chloride and sodium borohydride as reducing agents. As-prepared gold nanoparticles shows very excellent antifungal activity against Candida isolates and activity increases with decrease in the particle size. Display Omitted Highlights: ► Effect of reducing agents on the morphology of gold nanoparticles. ► Highly uniform and monodisperse gold nanoparticles (7 nm). ► Highest surface area of gold nanoparticles (329 m{sup 2/}g). ► Excellent antifungal activity of gold nanoparticles against Candida strains. -- Abstract:more » Gold nanoparticles have been successfully synthesized by solvothermal method using SnCl{sub 2} and NaBH{sub 4} as reducing agents. X-ray diffraction studies show highly crystalline and monophasic nature of the gold nanoparticles with face centred cubic structure. The transmission electron microscopic studies show the formation of nearly spherical gold nanoparticles of average size of 15 nm using SnCl{sub 2}, however, NaBH{sub 4} produced highly uniform, monodispersed and spherical gold nanoparticles of average grain size of 7 nm. A high surface area of 329 m{sup 2}/g for 7 nm and 269 m{sup 2}/g for 15 nm gold nanoparticles was observed. UV–vis studies assert the excitations over the visible region due to transverse and longitudinal surface plasmon modes. The gold nanoparticles exhibit excellent size dependant antifungal activity and greater biocidal action against Candida isolates for 7 nm sized gold nanoparticles restricting the transmembrane H{sup +} efflux of the Candida species than 15 nm sized gold nanoparticles.« less

Biomimetic High Density Lipoprotein Nanoparticles For Nucleic Acid Delivery

PubMed Central

McMahon, Kaylin M.; Mutharasan, R. Kannan; Tripathy, Sushant; Veliceasa, Dorina; Bobeica, Mariana; Shumaker, Dale K.; Luthi, Andrea J.; Helfand, Brian T.; Ardehali, Hossein; Mirkin, Chad A.; Volpert, Olga; Thaxton, C. Shad

2014-01-01

We report a gold nanoparticle-templated high density lipoprotein (HDL AuNP) platform for gene therapy which combines lipid-based nucleic acid transfection strategies with HDL biomimicry. For proof-of-concept, HDL AuNPs are shown to adsorb antisense cholesterylated DNA. The conjugates are internalized by human cells, can be tracked within cells using transmission electron microscopy (TEM), and regulate target gene expression. Overall, the ability to directly image the AuNP core within cells, the chemical tailorability of the HDL AuNP platform, and the potential for cell-specific targeting afforded by HDL biomimicry make this platform appealing for nucleic acid delivery. PMID:21319839

Ordering nanoparticles with polymer brushes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Shengfeng; Stevens, Mark J.; Grest, Gary S.

Ordering nanoparticles into a desired super-structure is often crucial for their technological applications. We use molecular dynamics simulations to study the assembly of nanoparticles in a polymer brush randomly grafted to a planar surface as the solvent evaporates. Initially, the nanoparticles are dispersed in a solvent that wets the polymer brush. After the solvent evaporates, the nanoparticles are either inside the brush or adsorbed at the surface of the brush, depending on the strength of the nanoparticle-polymer interaction. For strong nanoparticle-polymer interactions, a 2-dimensional ordered array is only formed when the brush density is finely tuned to accommodate a singlemore » layer of nanoparticles. When the brush density is higher or lower than this optimal value, the distribution of nanoparticles shows large fluctuations in space and the packing order diminishes. For weak nanoparticle-polymer interactions, the nanoparticles order into a hexagonal array on top of the polymer brush as long as the grafting density is high enough to yield a dense brush. As a result, an interesting healing effect is observed for a low-grafting-density polymer brush that can become more uniform in the presence of weakly adsorbed nanoparticles.« less

Ordering nanoparticles with polymer brushes

NASA Astrophysics Data System (ADS)

Cheng, Shengfeng; Stevens, Mark J.; Grest, Gary S.

2017-12-01

Ordering nanoparticles into a desired super-structure is often crucial for their technological applications. We use molecular dynamics simulations to study the assembly of nanoparticles in a polymer brush randomly grafted to a planar surface as the solvent evaporates. Initially, the nanoparticles are dispersed in a solvent that wets the polymer brush. After the solvent evaporates, the nanoparticles are either inside the brush or adsorbed at the surface of the brush, depending on the strength of the nanoparticle-polymer interaction. For strong nanoparticle-polymer interactions, a 2-dimensional ordered array is only formed when the brush density is finely tuned to accommodate a single layer of nanoparticles. When the brush density is higher or lower than this optimal value, the distribution of nanoparticles shows large fluctuations in space and the packing order diminishes. For weak nanoparticle-polymer interactions, the nanoparticles order into a hexagonal array on top of the polymer brush as long as the grafting density is high enough to yield a dense brush. An interesting healing effect is observed for a low-grafting-density polymer brush that can become more uniform in the presence of weakly adsorbed nanoparticles.

Ordering nanoparticles with polymer brushes

DOE PAGES

Cheng, Shengfeng; Stevens, Mark J.; Grest, Gary S.

2017-12-08

Ordering nanoparticles into a desired super-structure is often crucial for their technological applications. We use molecular dynamics simulations to study the assembly of nanoparticles in a polymer brush randomly grafted to a planar surface as the solvent evaporates. Initially, the nanoparticles are dispersed in a solvent that wets the polymer brush. After the solvent evaporates, the nanoparticles are either inside the brush or adsorbed at the surface of the brush, depending on the strength of the nanoparticle-polymer interaction. For strong nanoparticle-polymer interactions, a 2-dimensional ordered array is only formed when the brush density is finely tuned to accommodate a singlemore » layer of nanoparticles. When the brush density is higher or lower than this optimal value, the distribution of nanoparticles shows large fluctuations in space and the packing order diminishes. For weak nanoparticle-polymer interactions, the nanoparticles order into a hexagonal array on top of the polymer brush as long as the grafting density is high enough to yield a dense brush. As a result, an interesting healing effect is observed for a low-grafting-density polymer brush that can become more uniform in the presence of weakly adsorbed nanoparticles.« less

Optimization of synthesis and peptization steps to obtain iron oxide nanoparticles with high energy dissipation rates

NASA Astrophysics Data System (ADS)

Mérida, Fernando; Chiu-Lam, Andreina; Bohórquez, Ana C.; Maldonado-Camargo, Lorena; Pérez, María-Eglée; Pericchi, Luis; Torres-Lugo, Madeline; Rinaldi, Carlos

2015-11-01

Magnetic Fluid Hyperthermia (MFH) uses heat generated by magnetic nanoparticles exposed to alternating magnetic fields to cause a temperature increase in tumors to the hyperthermia range (43-47 °C), inducing apoptotic cancer cell death. As with all cancer nanomedicines, one of the most significant challenges with MFH is achieving high nanoparticle accumulation at the tumor site. This motivates development of synthesis strategies that maximize the rate of energy dissipation of iron oxide magnetic nanoparticles, preferable due to their intrinsic biocompatibility. This has led to development of synthesis strategies that, although attractive from the point of view of chemical elegance, may not be suitable for scale-up to quantities necessary for clinical use. On the other hand, to date the aqueous co-precipitation synthesis, which readily yields gram quantities of nanoparticles, has only been reported to yield sufficiently high specific absorption rates after laborious size selective fractionation. This work focuses on improvements to the aqueous co-precipitation of iron oxide nanoparticles to increase the specific absorption rate (SAR), by optimizing synthesis conditions and the subsequent peptization step. Heating efficiencies up to 1048 W/gFe (36.5 kA/m, 341 kHz; ILP=2.3 nH m2 kg-1) were obtained, which represent one of the highest values reported for iron oxide particles synthesized by co-precipitation without size-selective fractionation. Furthermore, particles reached SAR values of up to 719 W/gFe (36.5 kA/m, 341 kHz; ILP=1.6 nH m2 kg-1) when in a solid matrix, demonstrating they were capable of significant rates of energy dissipation even when restricted from physical rotation. Reduction in energy dissipation rate due to immobilization has been identified as an obstacle to clinical translation of MFH. Hence, particles obtained with the conditions reported here have great potential for application in nanoscale thermal cancer therapy.

Spectroscopic study of gold nanoparticle formation through high intensity laser irradiation of solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakamura, Takahiro, E-mail: nakamu@tagen.tohoku.ac.jp; Sato, Shunichi; Herbani, Yuliati

A spectroscopic study of the gold nanoparticle (NP) formation by high-intensity femtosecond laser irradiation of a gold ion solution was reported. The effect of varying energy density of the laser on the formation of gold NPs was also investigated. The surface plasmon resonance (SPR) peak of the gold nanocolloid in real-time UV-visible absorption spectra during laser irradiation showed a distinctive progress; the SPR absorption peak intensity increased after a certain irradiation time, reached a maximum and then gradually decreased. During this absorption variation, at the same time, the peak wavelength changed from 530 to 507 nm. According to an empiricalmore » equation derived from a large volume of experimental data, the estimated mean size of the gold NPs varied from 43.4 to 3.2 nm during the laser irradiation. The mean size of gold NPs formed at specific irradiation times by transmission electron microscopy showed the similar trend as that obtained in the spectroscopic analysis. From these observations, the formation mechanism of gold NPs during laser irradiation was considered to have two steps. The first is a reduction of gold ions by reactive species produced through a non-linear reaction during high intensity laser irradiation of the solution; the second is the laser fragmentation of produced gold particles into smaller pieces. The gold nanocolloid produced after the fragmentation by excess irradiation showed high stability for at least a week without the addition of any dispersant because of the negative charge on the surface of the nanoparticles probably due to the surface oxidation of gold nanoparticles. A higher laser intensity resulted in a higher efficiency of gold NPs fabrication, which was attributed to a larger effective volume of the reaction.« less

A high brightness probe of polymer nanoparticles for biological imaging

NASA Astrophysics Data System (ADS)

Zhou, Sirong; Zhu, Jiarong; Li, Yaping; Feng, Liheng

2018-03-01

Conjugated polymer nanoparticles (CPNs) with high brightness in long wavelength region were prepared by the nano-precipitation method. Based on fluorescence resonance energy transfer (FRET) mechanism, the high brightness property of the CPNs was realized by four different emission polymers. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) displayed that the CPNs possessed a spherical structure and an average diameter of 75 nm. Analysis assays showed that the CPNs had excellent biocompatibility, good photostability and low cytotoxicity. The CPNs were bio-modified with a cell penetrating peptide (Tat, a targeted element) through covalent link. Based on the entire wave fluorescence emission, the functionalized CPNs1-4 can meet multichannel and high throughput assays in cell and organ imaging. The contribution of the work lies in not only providing a new way to obtain a high brightness imaging probe in long wavelength region, but also using targeted cell and organ imaging.

Effects of Nanoparticle Size on Cellular Uptake and Liver MRI with PVP-Coated Iron Oxide Nanoparticles

PubMed Central

Huang, Jing; Bu, Lihong; Xie, Jin; Chen, Kai; Cheng, Zhen; Li, Xingguo; Chen, Xiaoyuan

2010-01-01

The effect of nanoparticle size (30–120 nm) on magnetic resonance imaging (MRI) of hepatic lesions in vivo has been systematically examined using polyvinylpyrrolidone (PVP)-coated iron oxide nanoparticles (PVP-IOs). Such biocompatible PVP-IOs with different sizes were synthesized by a simple one-pot pyrolysis method. These PVP-IOs exhibited good crystallinity and high T2 relaxivities, and the relaxivity increased with the size of the magnetic nanoparticles. It was found that cellular uptake changed with both size and surface physiochemical properties, and that PVP-IO-37 with a core size of 37 nm and hydrodynamic particle size of 100 nm exhibited higher cellular uptake rate and greater distribution than other PVP-IOs and Feridex. We systematically investigated the effect of nanoparticle size on MRI of normal liver and hepatic lesions in vivo. The physical and chemical properties of the nanoparticles influenced their pharmacokinetic behavior, which ultimately determined their ability to accumulate in the liver. The contrast enhancement of PVP-IOs within the liver was highly dependent on the overall size of the nanoparticles, and the 100 nm PVP-IO-37 nanoparticles exhibited the greatest enhancement. These results will have implications in designing engineered nanoparticles that are optimized as MR contrast agents or for use in therapeutics. PMID:21043459

Nanoparticle-assisted high photoconductive gain in polymer/fullerene matrix

PubMed Central

Chen, Hsiang-Yu; Lo, Michael K. F.; Yang, Guanwen; Monbouquette, Harold G.; Yang, Yang

2014-01-01

Polymer/inorganic nanocrystal composites1–10 offer an attractive means to combine the merits of organic and inorganic materials into novel electronic and photonic systems. However, many applications of these composites are limited by the solubility11 and distribution of nanocrystals (NCs) in polymer matrices. Here, a high photoconductive gain has been achieved by blending cadmium telluride (CdTe) nanoparticles (NPs) into a polymer/fullerene matrix followed by a solvent annealing12 process. The NP surface capping ligand, N-phenyl-N’-methyldithiocarbamate, renders the NPs highly soluble in the polymer blend thereby enabling high nanocrystal loadings. An external quantum efficiency (EQE) as high as ~8000% (at 350nm) is reached at −4.5V. Hole-dominant devices coupled with AFM images are studied to uncover the probable mechanism. We observe a higher concentration of CdTe NPs is located near the cathode/polymer interface. These NPs with trapped electrons assist hole injection into the polymer under reverse bias, which contributes to greater than 100% EQE. PMID:18772915

Carbon nanotubes decorated with Pt nanoparticles via electrostatic self-assembly: a highly active oxygen reduction electrocatalyst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Sheng; Shao, Yuyan; Yin, Geping

2010-03-20

Carbon nanotubes (CNTs) are noncovalently functionalized with poly(allylamine hydrochloride) (PAH) and then employed as the support of Pt nanoparticles. X-Ray photoelectron spectroscopy confirms the successful functionalization of CNTs with PAH. The negatively charged Pt precursors are adsorbed on positively charged PAH-wrapping CNTs surface via electrostatic self-assembly and then in situ reduced in ethylene glycol. X-Ray diffraction and transmission electron microscope images reveal that Pt nanoparticles with an average size of 2.6 nm are uniformly dispersed on CNT surface. Pt/PAH-CNTs exhibit unexpectedly high activity towards oxygen reduction reaction, which can be attributed to the large electrochemical surface area of Pt nanoparticles.more » It also shows enhanced electrochemical stability due to the structural integrity of PAH-CNTs. This provides a facile approach to synthesize CNTs-based nanoelectrocatalysts.« less

High-Resolution Large-Ensemble Nanoparticle Trapping with Multifunctional Thermoplasmonic Nanohole Metasurface.

PubMed

Ndukaife, Justus C; Xuan, Yi; Nnanna, Agbai George Agwu; Kildishev, Alexander V; Shalaev, Vladimir M; Wereley, Steven T; Boltasseva, Alexandra

2018-06-07

The intrinsic loss in a plasmonic metasurface is usually considered to be detrimental for device applications. Using plasmonic loss to our advantage, we introduce a thermoplasmonic metasurface that enables high-throughput large-ensemble nanoparticle assembly in a lab-on-a-chip platform. In our work, an array of subwavelength nanoholes in a metal film is used as a plasmonic metasurface that supports the excitation of localized surface plasmon and Bloch surface plasmon polariton waves upon optical illumination and provides a platform for molding both optical and thermal landscapes to achieve a tunable many-particle assembling process. The demonstrated many-particle trapping occurs against gravity in an inverted configuration where the light beam first passes through the nanoparticle suspension before illuminating the thermoplasmonic metasurface, a feat previously thought to be impossible. We also report an extraordinarily enhanced electrothermoplasmonic flow in the region of the thermoplasmonic nanohole metasurface, with comparatively larger transport velocities in comparison to the unpatterned region. This thermoplasmonic metasurface could enable possibilities for myriad applications in molecular analysis, quantum photonics, and self-assembly and creates a versatile platform for exploring nonequilibrium physics.

Cytocompatibility and biocompatibility of nanostructured carbonated hydroxyapatite spheres for bone repair

PubMed Central

CALASANS-MAIA, Mônica Diuana; de MELO, Bruno Raposo; ALVES, Adriana Terezinha Neves Novellino; RESENDE, Rodrigo Figueiredo de Brito; LOURO, Rafael Seabra; SARTORETTO, Suelen Cristina; GRANJEIRO, José Mauro; ALVES, Gutemberg Gomes

2015-01-01

ABSTRACT Objective The aim of this study was to investigate the in vitro and in vivo biological responses to nanostructured carbonated hydroxyapatite/calcium alginate (CHA) microspheres used for alveolar bone repair, compared to sintered hydroxyapatite (HA). Material and Methods The maxillary central incisors of 45 Wistar rats were extracted, and the dental sockets were filled with HA, CHA, and blood clot (control group) (n=5/period/group). After 7, 21 and 42 days, the samples of bone with the biomaterials were obtained for histological and histomorphometric analysis, and the plasma levels of RANKL and OPG were determined via immunoassay. Statistical analysis was performed by Two-Way ANOVA with post-hoc Tukey test at 95% level of significance. Results The CHA and HA microspheres were cytocompatible with both human and murine cells on an in vitro assay. Histological analysis showed the time-dependent increase of newly formed bone in control group characterized by an intense osteoblast activity. In HA and CHA groups, the presence of a slight granulation reaction around the spheres was observed after seven days, which was reduced by the 42nd day. A considerable amount of newly formed bone was observed surrounding the CHA spheres and the biomaterials particles at 42-day time point compared with HA. Histomorphometric analysis showed a significant increase of newly formed bone in CHA group compared with HA after 21 and 42 days from surgery, moreover, CHA showed almost 2-fold greater biosorption than HA at 42 days (two-way ANOVA, p<0.05) indicating greater biosorption. An increase in the RANKL/OPG ratio was observed in the CHA group on the 7th day. Conclusion CHA spheres were osteoconductive and presented earlier biosorption, inducing early increases in the levels of proteins involved in resorption. PMID:26814461

PEGylated hybrid ytterbia nanoparticles as high-performance diagnostic probes for in vivo magnetic resonance and X-ray computed tomography imaging with low systemic toxicity

NASA Astrophysics Data System (ADS)

Liu, Zhen; Pu, Fang; Liu, Jianhua; Jiang, Liyan; Yuan, Qinghai; Li, Zhengqiang; Ren, Jinsong; Qu, Xiaogang

2013-05-01

Novel nanoparticulate contrast agents with low systemic toxicity and inexpensive character have exhibited more advantages over routinely used small molecular contrast agents for the diagnosis and prognosis of disease. Herein, we designed and synthesized PEGylated hybrid ytterbia nanoparticles as high-performance nanoprobes for X-ray computed tomography (CT) imaging and magnetic resonance (MR) imaging both in vitro and in vivo. These well-defined nanoparticles were facile to prepare and cost-effective, meeting the criteria as a biomedical material. Compared with routinely used Iobitridol in clinic, our PEG-Yb2O3:Gd nanoparticles could provide much significantly enhanced contrast upon various clinical voltages ranging from 80 kVp to 140 kVp owing to the high atomic number and well-positioned K-edge energy of ytterbium. By the doping of gadolinium, our nanoparticulate contrast agent could perform perfect MR imaging simultaneously, revealing similar organ enrichment and bio-distribution with the CT imaging results. The super improvement in imaging efficiency was mainly attributed to the high content of Yb and Gd in a single nanoparticle, thus making these nanoparticles suitable for dual-modal diagnostic imaging with a low single-injection dose. In addition, detailed toxicological study in vitro and in vivo indicated that uniformly sized PEG-Yb2O3:Gd nanoparticles possessed excellent biocompatibility and revealed overall safety.Novel nanoparticulate contrast agents with low systemic toxicity and inexpensive character have exhibited more advantages over routinely used small molecular contrast agents for the diagnosis and prognosis of disease. Herein, we designed and synthesized PEGylated hybrid ytterbia nanoparticles as high-performance nanoprobes for X-ray computed tomography (CT) imaging and magnetic resonance (MR) imaging both in vitro and in vivo. These well-defined nanoparticles were facile to prepare and cost-effective, meeting the criteria as a biomedical material

Phase assemblage study and cytocompatibility property of heat treated potassium magnesium phosphate-silicate ceramics.

PubMed

Kumar, Ravi; Kalmodia, Sushma; Nath, Shekhar; Singh, Dileep; Basu, Bikramjit

2009-08-01

This article reports the study on a new generation bioactive ceramic, based on MgKPO(4) (Magnesium Potassium Phosphate, abbreviated as MKP) for biomedical applications. A series of heat treatment experiments on the slip cast silica (SiO(2)) containing MKP ceramics were carried out at 900, 1,000 and 1,100 degrees C for 4 h in air. The density of the slip cast ceramic increases to 2.5 gm/cm(3) upon heat treatment at 900 degrees C. However, no significant change in density is measured upon heat treatment to higher temperature of 1,000 and 1,100 degrees C. On the basis of XRD results, the presence of K(2)MgSi(5)O(12) and dehydrated MgKPO(4) were confirmed and complementary information has also been obtained using FT-IR and Raman spectroscopy. In order to confirm the in vitro cytocompatibility property, the cell culture tests were carried out on selected samples and the results reveal good cell adhesion and spreading of L929 mouse fibroblast cells. MTT assay analysis with L929 cells confirmed non-cytotoxic behavior of MKP containing ceramics and the results are comparable with sintered HAp ceramics. It is expected that the newly developed MKP based materials could be a good substitute for hydroxyapatite (HAp or HA) based bioceramics.

Mesquite Gum as a Novel Reducing and Stabilizing Agent for Modified Tollens Synthesis of Highly Concentrated Ag Nanoparticles

PubMed Central

Moreno-Trejo, Maira Berenice; Sánchez-Domínguez, Margarita

2016-01-01

The synthesis that is described in this study is for the preparation of silver nanoparticles of sizes ranging from 10 nm to 30 nm with a defined shape (globular), confirmed by UV-vis, SEM, STEM and DLS analysis. This simple and favorable one-step modified Tollens reaction does not require any special equipment or other stabilizing or reducing agent except for a solution of purified mesquite gum, and it produces aqueous colloidal dispersions of silver nanoparticles with a stability that exceeds three months, a relatively narrow size distribution, a low tendency to aggregate and a yield of at least 95% for all cases. Reaction times are between 15 min and 60 min to obtain silver nanoparticles in concentrations ranging from 0.1 g to 3 g of Ag per 100 g of reaction mixture. The proposed synthetic method presents a high potential for scale-up, since its production capacity is rather high and the methodology is simple. PMID:28773938

Monitoring nanoparticle-mediated cellular hyperthermia with a high-sensitivity biosensor

PubMed Central

Mukherjee, Amarnath; Castanares, Mark; Hedayati, Mohammad; Wabler, Michele; Trock, Bruce; Kulkarni, Prakash; Rodriguez, Ronald; Getzenberg, Robert H; DeWeese, Theodore L; Ivkov, Robert; Lupold, Shawn E

2014-01-01

Aim To develop and apply a heat-responsive and secreted reporter assay for comparing cellular response to nanoparticle (NP)- and macroscopic-mediated sublethal hyperthermia. Materials & methods Reporter cells were heated by water bath (macroscopic heating) or iron oxide NPs activated by alternating magnetic fields (nanoscopic heating). Cellular responses to these thermal stresses were measured in the conditioned media by secreted luciferase assay. Results & conclusion Reporter activity was responsive to macroscopic and nanoparticle heating and activity correlated with measured macroscopic thermal dose. Significant cellular responses were observed with NP heating under doses that were insufficient to measurably change the temperature of the system. Under these conditions, the reporter response correlated with proximity to cells loaded with heated nanoparticles. These results suggest that NP and macroscopic hyperthermia may be distinctive under conditions of mild hyperthermia. PMID:24547783

Hierarchical TiN nanoparticles-assembled nanopillars for flexible supercapacitors with high volumetric capacitance.

PubMed

Qin, Ping; Li, Xingxing; Gao, Biao; Fu, Jijiang; Xia, Lu; Zhang, Xuming; Huo, Kaifu; Shen, Wenli; Chu, Paul K

2018-05-10

Titanium nitride (TiN) is an attractive electrode material in fast charging/discharging supercapacitors because of its excellent conductivity. However, the low capacitance and mechanical brittleness of TiN restricts its further application in flexible supercapacitors with high energy density. Thus, it is still a challenge to rationally design TiN electrodes with both high electrochemical and mechanical properties. Herein, the hierarchical TiN nanoparticles-assembled nanopillars (H-TiN NPs) array as binder free electrodes were obtained by nitriding of hierarchical titanium dioxide (TiO2) nanopillars, which was produced by a simple hydrothermal treatment of anodic TiO2 nanotubes (NTs) array in water. The porous TiN nanoparticles connected to each other to form ordered nanopillar arrays, effectively providing larger specific surface area and more active sites for charge storage. The H-TiN NPs delivered a high volumetric capacitance of 120 F cm-3 at 0.83 A cm-3, which is better than that of TiN NTs arrays (69 F cm-3 at 0.83 A cm-3). After assembling into all-solid-state devices, the H-TiN NPs based supercapacitors exhibited outstanding volumetric capacitance of 5.9 F cm-3 at 0.02 A cm-3 and a high energy density of 0.53 mW h cm-3. Our results reveal a new strategy to optimize the supercapacitive performance of metal nitrides.

Dye-doped silica-based nanoparticles for bioapplications

NASA Astrophysics Data System (ADS)

Nhung Tran, Hong; Nghiem, Thi Ha Lien; Thuy Duong Vu, Thi; Tan Pham, Minh; Van Nguyen, Thi; Trang Tran, Thu; Chu, Viet Ha; Thuan Tong, Kim; Thuy Tran, Thanh; Le, Thi Thanh Xuan; Brochon, Jean-Claude; Quy Nguyen, Thi; Nhung Hoang, My; Nguyen Duong, Cao; Thuy Nguyen, Thi; Hoang, Anh Tuan; Hoa Nguyen, Phuong

2013-12-01

This paper presents our recent research results on synthesis and bioapplications of dye-doped silica-based nanoparticles. The dye-doped water soluble organically modified silicate (ORMOSIL) nanoparticles (NPs) with the size of 15-100 nm were synthesized by modified Stöber method from methyltriethoxysilane CH3Si(OCH3)3 precursor (MTEOS). Because thousands of fluorescent dye molecules are encapsulated in the silica-based matrix, the dye-doped nanoparticles are extremely bright and photostable. Their surfaces were modified with bovine serum albumin (BSA) and biocompatible chemical reagents. The highly intensive luminescent nanoparticles were combined with specific bacterial and breast cancer antigen antibodies. The antibody-conjugated nanoparticles can identify a variety of bacterium, such as Escherichia coli O157:H7, through antibody-antigen interaction and recognition. A highly sensitive breast cancer cell detection has been achieved with the anti-HER2 monoclonal antibody-nanoparticles complex. These results demonstrate the potential to apply these fluorescent nanoparticles in various biodetection systems.

High-yield aqueous synthesis of multi-branched iron oxide core-gold shell nanoparticles: SERS substrate for immobilization and magnetic separation of bacteria

NASA Astrophysics Data System (ADS)

Tamer, Ugur; Onay, Aykut; Ciftci, Hakan; Bozkurt, Akif Göktuğ; Cetin, Demet; Suludere, Zekiye; Hakkı Boyacı, İsmail; Daniel, Philippe; Lagarde, Fabienne; Yaacoub, Nader; Greneche, Jean-Marc

2014-10-01

The high product yield of multi-branched core-shell Fe3- x O4@Au magnetic nanoparticles was synthesized used as magnetic separation platform and surface-enhanced Raman scattering (SERS) substrates. The multi-branched magnetic nanoparticles were prepared by a seed-mediated growth approach using magnetic gold nanospheres as the seeds and subsequent reduction of metal salt with ascorbic acid in the presence of a stabilizing agent chitosan biopolymer and silver ions. The anisotropic growth of nanoparticles was observed in the presence of chitosan polymer matrix resulting in multi-branched nanoparticles with a diameter over 100 nm, and silver ions also play a crucial role on the growth of multi-branched nanoparticles. We propose the mechanism of the formation of multi-branched nanoparticles while the properties of nanoparticles embedded in chitosan matrix are discussed. The surface morphology of nanoparticles was characterized with transmission electron microscopy, scanning electron microscopy, ultraviolet visible spectroscopy (UV-Vis), X-ray diffraction, and fourier transform infrared spectroscopy and 57Fe Mössbauer spectrometry. Additionally, the magnetic properties of the nanoparticles were also examined. We also demonstrated that the synthesized Fe3- x O4@Au multi-branched nanoparticle is capable of targeted separation of pathogens from matrix and sensing as SERS substrates.

High photocatalytic activity of mixed anatase-rutile phases on commercial TiO2 nanoparticles

NASA Astrophysics Data System (ADS)

Ruu Siah, Wai; Lintang, Hendrik O.; Shamsuddin, Mustaffa; Yuliati, Leny

2016-02-01

Titanium dioxide (TiO2) is well-known as an active photocatalyst for degradation of various organic pollutants. Over the years, a wide range of TiO2 nanoparticles with different phase compositions, crystallinities, and surface areas have been developed. Due to the different methods and conditions used to synthesize these commercial TiO2 nanoparticles, the properties and photocatalytic performance would also be different from each other. In this study, the photocatalytic removal of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5- trichlorophenoxyacetic acid (2,4,5-T) was investigated on commercial Evonik P25, Evonik P90, Hombikat UV100 and Hombikat N100 TiO2 nanoparticles. Upon photocatalytic tests, it was found that overall, the photocatalytic activities of the P25 and the P90 were higher than the N100 and the UV100 for the removal of both 2,4-D and 2,4,5-T. The high activities of the P25 and the P90 could be attributed to their phase compositions, which are made up of a mixture of anatase and rutile phases of TiO2. Whereas, the UV100 and the N100 are made up of 100% anatase phase of TiO2. The synergistic effect of the anatase/rutile mixture was reported to slow down the recombination rate of photogenerated electron-hole pairs. Consequently, the photocatalytic activity was increased on these TiO2 nanoparticles.

Nitride stabilized core/shell nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuttiyiel, Kurian Abraham; Sasaki, Kotaro; Adzic, Radoslav R.

Nitride stabilized metal nanoparticles and methods for their manufacture are disclosed. In one embodiment the metal nanoparticles have a continuous and nonporous noble metal shell with a nitride-stabilized non-noble metal core. The nitride-stabilized core provides a stabilizing effect under high oxidizing conditions suppressing the noble metal dissolution during potential cycling. The nitride stabilized nanoparticles may be fabricated by a process in which a core is coated with a shell layer that encapsulates the entire core. Introduction of nitrogen into the core by annealing produces metal nitride(s) that are less susceptible to dissolution during potential cycling under high oxidizing conditions.

Cobalt nanoparticles/nitrogen-doped graphene with high nitrogen doping efficiency as noble metal-free electrocatalysts for oxygen reduction reaction.

PubMed

Liang, Jingwen; Hassan, Mehboob; Zhu, Dongsheng; Guo, Liping; Bo, Xiangjie

2017-03-15

Nitrogen-doped graphene (N/GR) has been considered as active metal-free electrocatalysts for oxygen reduction reaction (ORR). However, the nitrogen (N) doping efficiency is very low and only few N atoms are doped into the framework of GR. To boost the N doping efficiency, in this work, a confined pyrolysis method with high N doping efficiency is used for the preparation of cobalt nanoparticles/nitrogen-doped GR (Co/N/GR). Under the protection of SiO 2 , the inorganic ligand NH 3 in cobalt amine complex ([Co(NH 3 ) 6 ] 3+ ) is trapped in the confined space and then can be effectively doped into the framework of GR without the introduction of any carbon residues. Meanwhile, due to the redox reaction between the cobalt ions and carbon atoms of GR, Co nanoparticles are supported into the framework of N/GR. Due to prevention of GR layer aggregation with SiO 2 , the Co/N/GR with high dispersion provides sufficient surface area and maximum opportunity for the exposure of Co nanoparticles and active sites of N dopant. By combination of enhanced N doping efficiency, Co nanoparticles and high dispersion of GR sheets, the Co/N/GR is remarkably active, cheap and selective noble-metal free catalysts for ORR. Copyright © 2016 Elsevier Inc. All rights reserved.

Palladium Nanoparticle-Loaded Cellulose Paper: A Highly Efficient, Robust, and Recyclable Self-Assembled Composite Catalytic System.

PubMed

Zheng, Guangchao; Kaefer, Katharina; Mourdikoudis, Stefanos; Polavarapu, Lakshminarayana; Vaz, Belén; Cartmell, Samantha E; Bouleghlimat, Azzedine; Buurma, Niklaas J; Yate, Luis; de Lera, Ángel R; Liz-Marzán, Luis M; Pastoriza-Santos, Isabel; Pérez-Juste, Jorge

2015-01-15

We present a novel strategy based on the immobilization of palladium nanoparticles (Pd NPs) on filter paper for development of a catalytic system with high efficiency and recyclability. Oleylamine-capped Pd nanoparticles, dispersed in an organic solvent, strongly adsorb on cellulose filter paper, which shows a great ability to wick fluids due to its microfiber structure. Strong van der Waals forces and hydrophobic interactions between the particles and the substrate lead to nanoparticle immobilization, with no desorption upon further immersion in any solvent. The prepared Pd NP-loaded paper substrates were tested for several model reactions such as the oxidative homocoupling of arylboronic acids, the Suzuki cross-coupling reaction, and nitro-to-amine reduction, and they display efficient catalytic activity and excellent recyclability and reusability. This approach of using NP-loaded paper substrates as reusable catalysts is expected to open doors for new types of catalytic support for practical applications.

Applications of Nanoparticle-Containing Plasmas for High-Order Harmonic Generation of Laser Radiation

NASA Astrophysics Data System (ADS)

Ganeev, Rashid A.

The use of nanoparticles for efficient conversion of the wavelength of ultrashort laser toward the deep UV spectral range through harmonic generation is an attractive application of cluster-containing plasmas. Note that earlier observations of HHG in nanoparticles were limited by using the exotic gas clusters formed during fast cooling of atomic flow from the gas jets 1-4. One can assume the difficulties in definition of the structure of such clusters and the ratio between nanoparticles and atoms/ions in the gas flow. The characterization of gas phase cluster production was currently improved using the sophisticated techniques (e.g., a control of nanoparticle mass and spatial distribution, see the review 5). In the meantime, the plasma nanoparticle HHG has demonstrated some advantages over gas cluster HHG 6. The application of commercially available nanopowders allowed for precisely defining the sizes and structure of these clusters in the plume. The laser ablation technique made possible the predictable manipulation of plasma characteristics, which led to the creation of laser plumes containing mainly nanoparticles with known spatial structure. The latter allows the application of such plumes in nonlinear optics, X-ray emission of clusters, deposition of nanoparticles with fixed parameters on the substrates for semiconductor industry, production of nanostructured and nanocomposite films, etc.

Antimicrobial activity of biogenic silver nanoparticles, and silver chloride nanoparticles: an overview and comments.

PubMed

Durán, Nelson; Nakazato, Gerson; Seabra, Amedea B

2016-08-01

The antimicrobial impact of biogenic-synthesized silver-based nanoparticles has been the focus of increasing interest. As the antimicrobial activity of nanoparticles is highly dependent on their size and surface, the complete and adequate characterization of the nanoparticle is important. This review discusses the characterization and antimicrobial activity of biogenic synthesized silver nanoparticles and silver chloride nanoparticles. By revising the literature, there is confusion in the characterization of these two silver-based nanoparticles, which consequently affects the conclusion regarding to their antimicrobial activities. This review critically analyzes recent publications on the synthesis of biogenic silver nanoparticles and silver chloride nanoparticles by attempting to correlate the characterization of the nanoparticles with their antimicrobial activity. It was difficult to correlate the size of biogenic nanoparticles with their antimicrobial activity, since different techniques are employed for the characterization. Biogenic synthesized silver-based nanoparticles are not completely characterized, particularly the nature of capped proteins covering the nanomaterials. Moreover, the antimicrobial activity of theses nanoparticles is assayed by using different protocols and strains, which difficult the comparison among the published papers. It is important to select some bacteria as standards, by following international foundations (Pharmaceutical Microbiology Manual) and use the minimal inhibitory concentration by broth microdilution assays from Clinical and Laboratory Standards Institute, which is the most common assay used in antibiotic ones. Therefore, we conclude that to have relevant results on antimicrobial effects of biogenic silver-based nanoparticles, it is necessary to have a complete and adequate characterization of these nanostructures, followed by standard methodology in microbiology protocols.

Spectroscopic Characterization and Nanosafety of Ag-Modified Antibacterial Leather and Leatherette.

PubMed

Sportelli, Maria Chiara; Picca, Rosaria Anna; Paladini, Federica; Mangone, Annarosa; Giannossa, Lorena Carla; Franco, Cinzia Di; Gallo, Anna Lucia; Valentini, Antonio; Sannino, Alessandro; Pollini, Mauro; Cioffi, Nicola

2017-07-29

The development of antibacterial coatings is of great interest from both industry and the consumer's point of view. In this study, we characterized tanned leather and polyurethane leatherette, typically employed in the automotive and footwear industries, which were modified by photo-deposition of antibacterial silver nanoparticles (AgNPs). Material surface chemical composition was investigated in detail by X-ray photoelectron spectroscopy (XPS). The material's antibacterial capability was checked against Escherichia coli and Staphylococcus aureus , as representative microorganisms in cross transmissions. Due to the presence of silver in a nanostructured form, nanosafety issues were considered, as well. Ionic release in contact media, as well as whole nanoparticle release from treated materials, were quantitatively evaluated, thus providing specific information on potential product nanotoxicity, which was further investigated through cytocompatibility MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays, also after surface abrasion of the materials. The proved negligible nanoparticle release, as well as the controlled release of antibacterial ions, shed light on the materials' potentialities, in terms of both high activity and safety.

Spectroscopic Characterization and Nanosafety of Ag-Modified Antibacterial Leather and Leatherette

PubMed Central

Mangone, Annarosa; Di Franco, Cinzia; Gallo, Anna Lucia; Valentini, Antonio; Sannino, Alessandro

2017-01-01

The development of antibacterial coatings is of great interest from both industry and the consumer’s point of view. In this study, we characterized tanned leather and polyurethane leatherette, typically employed in the automotive and footwear industries, which were modified by photo-deposition of antibacterial silver nanoparticles (AgNPs). Material surface chemical composition was investigated in detail by X-ray photoelectron spectroscopy (XPS). The material’s antibacterial capability was checked against Escherichia coli and Staphylococcus aureus, as representative microorganisms in cross transmissions. Due to the presence of silver in a nanostructured form, nanosafety issues were considered, as well. Ionic release in contact media, as well as whole nanoparticle release from treated materials, were quantitatively evaluated, thus providing specific information on potential product nanotoxicity, which was further investigated through cytocompatibility MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays, also after surface abrasion of the materials. The proved negligible nanoparticle release, as well as the controlled release of antibacterial ions, shed light on the materials’ potentialities, in terms of both high activity and safety. PMID:28758912

High potential of Mn-doped ZnS nanoparticles with different dopant concentrations as novel MRI contrast agents: synthesis and in vitro relaxivity studies

NASA Astrophysics Data System (ADS)

Jahanbin, Tania; Gaceur, Meriem; Gros-Dagnac, Hélène; Benderbous, Soraya; Merah, Souad Ammar

2015-06-01

Over several decades, metal-doped quantum dots (QDs) with core-shell structure have been studied as dual probes: fluorescence and magnetic resonance imaging (MRI) probes (Dixit et al., Mater Lett 63(30):2669-2671, 2009). However, metal-doped nanoparticles, in which the majority of metal ions are close to the surface, can affect their efficacy as MRI contrast agents (CAs). In this context, herein the high potential of synthesized Mn-doped ZnS QDs via polyol method as imaging probe is demonstrated. The mean diameters of QDs were measured via transmission electron microscopy (TEM) and X-ray diffraction (XRD). Optical and magnetic properties of MnZnS nanoparticles were characterized using fluorescence spectroscopy and super quanducting interference devices magnetometer and electron paramagnetic resonance system, respectively. T1- and T2-weighted images of nanoparticles in aqueous solution were acquired from spin-echo sequences at 3 T. From TEM images and XRD spectra of the prepared nanoparticles, it is observed that the average diameter of particles does not significantly change with Mn dopant content ( 1.6-1.9 nm). All three samples exhibit broad blue emission under UV light excitation. According to the MRI studies, MnZnS nanoparticles generate strong T1 contrast enhancement (bright T1-weighted images) at the low concentration (<0.1 mM). The MnZnS nanoparticles exhibit the high longitudinal ( r 1) relaxivity that increases from 20.34 to 75.5 mM-1 s-1 with the Mn dopant contents varying between 10 and 30 %. Strong signal intensity on T1-weighted images and high r 1 with {r2 }/{r_{1 }} ≈ 1 can demonstrate the high potential of the synthesized Mn:ZnS nanoparticles, which can serve as an effective T1 CA.

Mesoporous silica templated zirconia nanoparticles

NASA Astrophysics Data System (ADS)

Ballem, Mohamed A.; Córdoba, José M.; Odén, Magnus

2011-07-01

Nanoparticles of zirconium oxide (ZrO2) were synthesized by infiltration of a zirconia precursor (ZrOCl2·8H2O) into a SBA-15 mesoporous silica mold using a wet-impregnation technique. X-ray diffractometry and high-resolution transmission electron microscopy show formation of stable ZrO2 nanoparticles inside the silica pores after a thermal treatment at 550 °C. Subsequent leaching out of the silica template by NaOH resulted in well-dispersed ZrO2 nanoparticles with an average diameter of 4 nm. The formed single crystal nanoparticles are faceted with 110 surfaces termination suggesting it to be the preferred growth orientation. A growth model of these nanoparticles is also suggested.

Highly scalable, closed-loop synthesis of drug-loaded, layer-by-layer nanoparticles.

PubMed

Correa, Santiago; Choi, Ki Young; Dreaden, Erik C; Renggli, Kasper; Shi, Aria; Gu, Li; Shopsowitz, Kevin E; Quadir, Mohiuddin A; Ben-Akiva, Elana; Hammond, Paula T

2016-02-16

Layer-by-layer (LbL) self-assembly is a versatile technique from which multicomponent and stimuli-responsive nanoscale drug carriers can be constructed. Despite the benefits of LbL assembly, the conventional synthetic approach for fabricating LbL nanoparticles requires numerous purification steps that limit scale, yield, efficiency, and potential for clinical translation. In this report, we describe a generalizable method for increasing throughput with LbL assembly by using highly scalable, closed-loop diafiltration to manage intermediate purification steps. This method facilitates highly controlled fabrication of diverse nanoscale LbL formulations smaller than 150 nm composed from solid-polymer, mesoporous silica, and liposomal vesicles. The technique allows for the deposition of a broad range of polyelectrolytes that included native polysaccharides, linear polypeptides, and synthetic polymers. We also explore the cytotoxicity, shelf life and long-term storage of LbL nanoparticles produced using this approach. We find that LbL coated systems can be reliably and rapidly produced: specifically, LbL-modified liposomes could be lyophilized, stored at room temperature, and reconstituted without compromising drug encapsulation or particle stability, thereby facilitating large scale applications. Overall, this report describes an accessible approach that significantly improves the throughput of nanoscale LbL drug-carriers that show low toxicity and are amenable to clinically relevant storage conditions.

Scalable synthesis of Fe₃O₄ nanoparticles anchored on graphene as a high-performance anode for lithium ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Yu Cheng; Center of Super-Diamond and Advanced Films; Ma, Ru Guang

2013-05-01

We report a scalable strategy to synthesize Fe₃O₄/graphene nanocomposites as a high-performance anode material for lithium ion batteries. In this study, ferric citrate is used as precursor to prepare Fe₃O₄ nanoparticles without introducing additional reducing agent; furthermore and show that such Fe₃O₄ nanoparticles can be anchored on graphene sheets which attributed to multifunctional group effect of citrate. Electrochemical characterization of the Fe₃O₄/graphene nanocomposites exhibit large reversible capacity (~1347 mA h g⁻¹ at a current density of 0.2 C up to 100 cycles, and subsequent capacity of ~619 mA h g⁻¹ at a current density of 2 C up to 200more » cycles), as well as high coulombic efficiency (~97%), excellent rate capability, and good cyclic stability. High resolution transmission electron microscopy confirms that Fe₃O₄ nanoparticles, with a size of ~4–16 nm are densely anchored on thin graphene sheets, resulting in large synergetic effects between Fe₃O₄ nanoparticles and graphene sheets with high electrochemical performance. - Graphical abstract: The reduction of Fe³⁺ to Fe²⁺ and the deposition of Fe₃O₄ on graphene sheets occur simultaneously using citrate function as reductant and anchor agent in this reaction process. Highlights: • Fe₃O₄/graphene composites are synthesized directly from graphene and C₆H₅FeO₇. • The citrate function as reductant and anchor agent in this reaction process. • The resulting Fe₃O₄ particles (~4–16 nm) are densely anchored on graphene sheets. • The prepared Fe₃O₄/graphene composites exhibit excellent electrochemical performance.« less

Ultrasound mediated nanoparticle drug delivery

NASA Astrophysics Data System (ADS)

Mullin, Lee B.

Ultrasound is not only a powerful diagnostic tool, but also a promising therapeutic technology that can be used to improve localized drug delivery. Microbubble contrast agents are micron sized encapsulated gas filled bubbles that are administered intravenously. Originally developed to enhance ultrasound images, microbubbles are highly echogenic due to the gas core that provides a detectable impedance difference from the surrounding medium. The core also allows for controlled response of the microbubbles to ultrasound pulses. Microbubbles can be pushed using acoustic radiation force and ruptured using high pressures. Destruction of microbubbles can increase permeability at the cellular and vascular level, which can be advantageous for drug delivery. Advances in drug delivery methods have been seen with the introduction of nanoparticles, nanometer sized objects often carrying a drug payload. In chemotherapy, nanoparticles can deliver drugs to tumors while limiting systemic exposure due to abnormalities in tumor vasculature such large gaps between endothelial cells that allow nanoparticles to enter into the interstitial space; this is referred to as the enhanced permeability and retention (EPR) effect. However, this effect may be overestimated in many tumors. Additionally, only a small percentage of the injected dose accumulates in the tumor, which most the nanoparticles accumulating in the liver and spleen. It is hypothesized that combining the acoustic activity of an ultrasound contrast agent with the high payload and extravasation ability of a nanoparticle, localized delivery to the tumor with reduced systemic toxicity can be achieved. This method can be accomplished by either loading nanoparticles onto the shell of the microbubble or through a coadministration method of both nanoparticles and microbubbles. The work presented in this dissertation utilizes novel and commercial nanoparticle formulations, combined with microbubbles and a variety of ultrasound systems

Reactive and non-reactive interactions of thiophene with WS2 fullerene-like nanoparticles: an ultra-high vacuum surface chemistry study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goering, J.; Burghaus, Uwe; Arey, Bruce W.

The adsorption kinetics of thiophene on WS2 nanoparticles with fullerene-like (onion-like) structure has been studied at ultra-high vacuum conditions by sample temperature ramping techniques. At low temperatures, thiophene adsorbs molecularly. The formation of H2S and alkanes is evident at greater temperatures on fully sulfided as well as reduced and oxidized WS2 nanoparticles.

Stability and Reactivity: Positive and Negative Aspects for Nanoparticle Processing.

PubMed

Xu, Liang; Liang, Hai-Wei; Yang, Yuan; Yu, Shu-Hong

2018-04-11

Nanoparticles exist far from the equilibrium state due to their high surface energy. Nanoparticles are therefore extremely unstable and easily change themselves or react with active substances to reach a relatively stable state in some cases. This causes desired changes or undesired changes to nanoparticles and thus makes them exhibit a high reactivity and a poor stability. Such dual nature (poor stability and high reactivity) of nanoparticles may result in both negative and positive effects for nanoparticle processing. However, the existing studies mainly focus on the high reactivity of nanoparticles, whereas their poor stability has been neglected or considered inconsequential. In fact, in some cases the unstable process, which is derived from the poor stability of nanoparticles, offers an opportunity to design and fabricate unique nanomaterials, such as by chemically transforming the "captured" intermediate nanostructures during a changing process, assembling destabilized nanoparticles into larger ordered assemblies, or shrinking/processing pristine materials into the desired size or shape via selective etching. In this review, we aim to present the stability and reactivity of nanoparticles on three levels: the foundation, concrete manifestations, and applications. We start with a brief introduction of dangling bonds and the surface chemistry of nanoparticles. Then, concrete manifestations of the poor stability and high reactivity of nanoparticles are presented from four perspectives: dispersion stability, thermal stability, structural stability, and chemical stability/reactivity. Next, we discuss some issues regarding the stability and reactivity of nanomaterials during applications. Finally, conclusions and perspectives on this field are presented.

Ga-Doped Pt-Ni Octahedral Nanoparticles as a Highly Active and Durable Electrocatalyst for Oxygen Reduction Reaction.

PubMed

Lim, JeongHoon; Shin, Hyeyoung; Kim, MinJoong; Lee, Hoin; Lee, Kug-Seung; Kwon, YongKeun; Song, DongHoon; Oh, SeKwon; Kim, Hyungjun; Cho, EunAe

2018-04-11

Bimetallic PtNi nanoparticles have been considered as a promising electrocatalyst for oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells (PEMFCs) owing to their high catalytic activity. However, under typical fuel cell operating conditions, Ni atoms easily dissolve into the electrolyte, resulting in degradation of the catalyst and the membrane-electrode assembly (MEA). Here, we report gallium-doped PtNi octahedral nanoparticles on a carbon support (Ga-PtNi/C). The Ga-PtNi/C shows high ORR activity, marking an 11.7-fold improvement in the mass activity (1.24 A mg Pt -1 ) and a 17.3-fold improvement in the specific activity (2.53 mA cm -2 ) compared to the commercial Pt/C (0.106 A mg Pt -1 and 0.146 mA cm -2 ). Density functional theory calculations demonstrate that addition of Ga to octahedral PtNi can cause an increase in the oxygen intermediate binding energy, leading to the enhanced catalytic activity toward ORR. In a voltage-cycling test, the Ga-PtNi/C exhibits superior stability to PtNi/C and the commercial Pt/C, maintaining the initial Ni concentration and octahedral shape of the nanoparticles. Single cell using the Ga-PtNi/C exhibits higher initial performance and durability than those using the PtNi/C and the commercial Pt/C. The majority of the Ga-PtNi nanoparticles well maintain the octahedral shape without agglomeration after the single cell durability test (30,000 cycles). This work demonstrates that the octahedral Ga-PtNi/C can be utilized as a highly active and durable ORR catalyst in practical fuel cell applications.

Robot-Based High-Throughput Engineering of Alcoholic Polymer: Fullerene Nanoparticle Inks for an Eco-Friendly Processing of Organic Solar Cells.

PubMed

Xie, Chen; Tang, Xiaofeng; Berlinghof, Marvin; Langner, Stefan; Chen, Shi; Späth, Andreas; Li, Ning; Fink, Rainer H; Unruh, Tobias; Brabec, Christoph J

2018-06-27

Development of high-quality organic nanoparticle inks is a significant scientific challenge for the industrial production of solution-processed organic photovoltaics (OPVs) with eco-friendly processing methods. In this work, we demonstrate a novel, robot-based, high-throughput procedure performing automatic poly(3-hexylthio-phene-2,5-diyl) and indene-C 60 bisadduct nanoparticle ink synthesis in nontoxic alcohols. A novel methodology to prepare particle dispersions for fully functional OPVs by manipulating the particle size and solvent system was studied in detail. The ethanol dispersion with a particle diameter of around 80-100 nm exhibits reduced degradation, yielding a power conversion efficiency of 4.52%, which is the highest performance reported so far for water/alcohol-processed OPV devices. By successfully deploying the high-throughput robot-based approach for an organic nanoparticle ink preparation, we believe that the findings demonstrated in this work will trigger more research interest and effort on eco-friendly industrial production of OPVs.

Optimization and characterization of high pressure homogenization produced chemically modified starch nanoparticles.

PubMed

Ding, Yongbo; Kan, Jianquan

2017-12-01

Chemically modified starch (RS4) nanoparticles were synthesized through homogenization and water-in-oil mini-emulsion cross-linking. Homogenization was optimized with regard to z-average diameter by using a three-factor-three-level Box-Behnken design. Homogenization pressure (X 1 ), oil/water ratio (X 2 ), and surfactant (X 3 ) were selected as independent variables, whereas z-average diameter was considered as a dependent variable. The following optimum preparation conditions were obtained to achieve the minimum average size of these nanoparticles: 50 MPa homogenization pressure, 10:1 oil/water ratio, and 2 g surfactant amount, when the predicted z-average diameter was 303.6 nm. The physicochemical properties of these nanoparticles were also determined. Dynamic light scattering experiments revealed that RS4 nanoparticles measuring a PdI of 0.380 and an average size of approximately 300 nm, which was very close to the predicted z-average diameter (303.6 nm). The absolute value of zeta potential of RS4 nanoparticles (39.7 mV) was higher than RS4 (32.4 mV), with strengthened swelling power. X-ray diffraction results revealed that homogenization induced a disruption in crystalline structure of RS4 nanoparticles led to amorphous or low-crystallinity. Results of stability analysis showed that RS4 nanosuspensions (particle size) had good stability at 30 °C over 24 h.

High-durability catalytic electrode composed of Pt nanoparticle-supported carbon nanowalls synthesized by radical-injection plasma-enhanced chemical vapor deposition

NASA Astrophysics Data System (ADS)

Imai, Shun; Kondo, Hiroki; Cho, Hyungjun; Kano, Hiroyuki; Ishikawa, Kenji; Sekine, Makoto; Hiramatsu, Mineo; Ito, Masafumi; Hori, Masaru

2017-10-01

For polymer electrolyte fuel cell applications, carbon nanowalls (CNWs) were synthesized by radical-injection plasma-enhanced chemical vapor deposition, and a high density of Pt nanoparticles (>1012 cm-2) was supported on the CNWs using a supercritical fluid deposition system. The high potential cycle tests were applied and the electrochemical surface area of the Pt nanoparticle-supported CNWs did not change significantly, even after 20 000 high potential cycles. According to transmission electron microscopy observations, the mean diameter of Pt changed slightly after the cycle tests, while the crystallinity of the CNWs evaluated using Raman spectroscopy showed almost no change.

High frequency electromagnetic reflection loss performance of substituted Sr-hexaferrite nanoparticles/SWCNTs/epoxy nanocomposite

NASA Astrophysics Data System (ADS)

Gordani, Gholam Reza; Ghasemi, Ali; saidi, Ali

2015-10-01

In this study, the electromagnetic properties of a novel nanocomposite material made of substituted Sr-hexaferrite nanoparticles and different percentage of single walled carbon nanotube have been studied. The structural, magnetic and electromagnetic properties of samples were studied as a function of volume percentage of SWCNTs by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer and vector network analysis. Well suitable crystallinity of hexaferrite nanoparticles was confirmed by XRD patterns. TEM and FESEM micrographs were shown the good homogenity and high level of dispersivity of SWCNTs and Sr-hexaferrite nanoparticles in nanocomposite samples. The VSM results shown that with increasing in amount of CNTs (0-6 vol%), the saturation of magnetization decreased up to 11 emu/g for nanocomposite sample contains of 6 vol% of SWCNTs. The vector network analysis results show that the maximum value of reflection loss was -36.4 dB at the frequency of 11 GHz with an absorption bandwidth of more than 4 GHz (<-20 dB). The results indicate that, this nanocomposite material with appropriate amount of SWCNTs hold great promise for microwave device applications.

Economically attractive route for the preparation of high quality magnetic nanoparticles by the thermal decomposition of iron(III) acetylacetonate.

PubMed

Effenberger, Fernando B; Couto, Ricardo A; Kiyohara, Pedro K; Machado, Giovanna; Masunaga, Sueli H; Jardim, Renato F; Rossi, Liane M

2017-03-17

The thermal decomposition (TD) methods are among the most successful in obtaining magnetic nanoparticles with a high degree of control of size and narrow particle size distribution. Here we investigated the TD of iron(III) acetylacetonate in the presence of oleic acid, oleylamine, and a series of alcohols in order to disclose their role and also investigate economically attractive alternatives for the synthesis of iron oxide nanoparticles without compromising their size and shape control. We have found that some affordable and reasonably less priced alcohols, such as 1,2-octanediol and cyclohexanol, may replace the commonly used and expensive 1,2-hexadecanediol, providing an economically attractive route for the synthesis of high quality magnetic nanoparticles. The relative cost for the preparation of Fe 3 O 4 NPs is reduced to only 21% and 9% of the original cost when using 1,2-octanediol and cyclohexanol, respectively.

Aptamer-Functionalized Fluorescent Silica Nanoparticles for Highly Sensitive Detection of Leukemia Cells

NASA Astrophysics Data System (ADS)

Tan, Juntao; Yang, Nuo; Hu, Zixi; Su, Jing; Zhong, Jianhong; Yang, Yang; Yu, Yating; Zhu, Jianmeng; Xue, Dabin; Huang, Yingying; Lai, Zongqiang; Huang, Yong; Lu, Xiaoling; Zhao, Yongxiang

2016-06-01

A simple, highly sensitive method to detect leukemia cells has been developed based on aptamer-modified fluorescent silica nanoparticles (FSNPs). In this strategy, the amine-labeled Sgc8 aptamer was conjugated to carboxyl-modified FSNPs via amide coupling between amino and carboxyl groups. Sensitivity and specificity of Sgc8-FSNPs were assessed using flow cytometry and fluorescence microscopy. These results showed that Sgc8-FSNPs detected leukemia cells with high sensitivity and specificity. Aptamer-modified FSNPs hold promise for sensitive and specific detection of leukemia cells. Changing the aptamer may allow the FSNPs to detect other types of cancer cells.

Directed liquid phase assembly of highly ordered metallic nanoparticle arrays

DOE PAGES

Wu, Yueying; Dong, Nanyi; Fu, Shaofang; ...

2014-04-01

Directed assembly of nanomaterials is a promising route for the synthesis of advanced materials and devices. We demonstrate the directed-assembly of highly ordered two-dimensional arrays of hierarchical nanostructures with tunable size, spacing and composition. The directed assembly is achieved on lithographically patterned metal films that are subsequently pulse-laser melted; during the brief liquid lifetime, the pattened nanostructures assemble into highly ordered primary and secondary nanoparticles, with sizes below that which was originally patterned. Complementary fluid-dynamics simulations emulate the resultant patterns and show how the competition of capillary forces and liquid metal–solid substrate interaction potential drives the directed assembly. Lastly, asmore » an example of the enhanced functionality, a full-wave electromagnetic analysis has been performed to identify the nature of the supported plasmonic resonances.« less

High content image analysis for human H4 neuroglioma cells exposed to CuO nanoparticles.

PubMed

Li, Fuhai; Zhou, Xiaobo; Zhu, Jinmin; Ma, Jinwen; Huang, Xudong; Wong, Stephen T C

2007-10-09

High content screening (HCS)-based image analysis is becoming an important and widely used research tool. Capitalizing this technology, ample cellular information can be extracted from the high content cellular images. In this study, an automated, reliable and quantitative cellular image analysis system developed in house has been employed to quantify the toxic responses of human H4 neuroglioma cells exposed to metal oxide nanoparticles. This system has been proved to be an essential tool in our study. The cellular images of H4 neuroglioma cells exposed to different concentrations of CuO nanoparticles were sampled using IN Cell Analyzer 1000. A fully automated cellular image analysis system has been developed to perform the image analysis for cell viability. A multiple adaptive thresholding method was used to classify the pixels of the nuclei image into three classes: bright nuclei, dark nuclei, and background. During the development of our image analysis methodology, we have achieved the followings: (1) The Gaussian filtering with proper scale has been applied to the cellular images for generation of a local intensity maximum inside each nucleus; (2) a novel local intensity maxima detection method based on the gradient vector field has been established; and (3) a statistical model based splitting method was proposed to overcome the under segmentation problem. Computational results indicate that 95.9% nuclei can be detected and segmented correctly by the proposed image analysis system. The proposed automated image analysis system can effectively segment the images of human H4 neuroglioma cells exposed to CuO nanoparticles. The computational results confirmed our biological finding that human H4 neuroglioma cells had a dose-dependent toxic response to the insult of CuO nanoparticles.

Spectroscopic and magnetic studies of highly dispersible superparamagnetic silica coated magnetite nanoparticles

NASA Astrophysics Data System (ADS)

Tadyszak, Krzysztof; Kertmen, Ahmet; Coy, Emerson; Andruszkiewicz, Ryszard; Milewski, Sławomir; Kardava, Irakli; Scheibe, Błażej; Jurga, Stefan; Chybczyńska, Katarzyna

2017-07-01

Superparamagnetic behavior in aqueously well dispersible magnetite core-shell Fe3O4@SiO2 nanoparticles is presented. The magnetic properties of core-shell nanoparticles were measured with use of the DC, AC magnetometry and EPR spectroscopy. Particles where characterized by HR-TEM and Raman spectroscopy, showing a crystalline magnetic core of 11.5 ± 0.12 nm and an amorphous silica shell of 22 ± 1.5 nm in thickness. The DC, AC magnetic measurements confirmed the superparamagnetic nature of nanoparticles, additionally the EPR studies performed at much higher frequency than DC, AC magnetometry (9 GHz) have confirmed the paramagnetic nature of the nanoparticles. Our results show the excellent magnetic behavior of the particles with a clear magnetite structure, which are desirable properties for environmental remediation and biomedical applications.

Cooling and manipulation of nanoparticles in high vacuum

NASA Astrophysics Data System (ADS)

Millen, J.; Kuhn, S.; Patolsky, F.; Kosloff, A.; Arndt, M.

2016-09-01

Optomechanical systems, where the mechanical motion of objects is measured and controlled using light, have a huge range of applications, from the metre-scale mirrors of LIGO which detect gravitational waves, to micron scale superconducting systems that can transduce quantum signals. A fascinating addition to this field are free or levitated optomechanical systems, where the oscillator is not physically tethered. We study a variety of nanoparticles which are launched through vacuum (10-8 mbar) and interact with an optical cavity. The centre of mass motion of a nanoparticle can be cooled by the optical cavity field. It is predicted that the quantum ground state of motion can be reached, leaving the particle free to evolve after release from the light field, thus preparing nanoscale matter for quantum interference experiments.

High-coercivity FePt nanoparticle assemblies embedded in silica thin films.

PubMed

Yan, Q; Purkayastha, A; Singh, A P; Li, H; Li, A; Ramanujan, R V; Ramanath, G

2009-01-14

The ability to process assemblies using thin film techniques in a scalable fashion would be a key to transmuting the assemblies into manufacturable devices. Here, we embed FePt nanoparticle assemblies into a silica thin film by sol-gel processing. Annealing the thin film composite at 650 degrees C transforms the chemically disordered fcc FePt phase into the fct phase, yielding magnetic coercivity values H(c)>630 mT. The positional order of the particles is retained due to the protection offered by the silica host. Such films with assemblies of high-coercivity magnetic particles are attractive for realizing new types of ultra-high-density data storage devices and magneto-composites.

High-density arrays of titania nanoparticles using monolayer micellar films of diblock copolymers as templates.

PubMed

Li, Xue; Lau, King Hang Aaron; Kim, Dong Ha; Knoll, Wolfgang

2005-05-24

Highly dense arrays of titania nanoparticles were fabricated using surface micellar films of poly(styrene-block-2-vinylpyridine) diblock copolymers (PS-b-P2VP) as reaction scaffolds. Titania could be introduced selectively within P2VP nanodomains in PS-b-P2VP films through the binary reaction between water molecules trapped in the P2VP domains and the TiCl(4) vapor precursors. Subsequent UV exposure or oxygen plasma treatment removed the organic matrix, leading to titania nanoparticle arrays on the substrate surface. The diameter of the titania domains and the interparticle distance were defined by the lateral scale present in the microphase-separated morphology of the initial PS-b-P2VP films. The typical diameter of titania nanoparticles obtained by oxygen plasma treatment was of the order of approximately 23 nm. Photoluminescence (PL) properties were investigated for films before and after plasma treatment. Both samples showed PL properties with major physical origin due to self-trapped excitons, indicating that the local environment of the titanium atoms is similar.

Densely-packed graphene/conducting polymer nanoparticle papers for high-volumetric-performance flexible all-solid-state supercapacitors

NASA Astrophysics Data System (ADS)

Yang, Chao; Zhang, Liling; Hu, Nantao; Yang, Zhi; Wei, Hao; Xu, Zhichuan J.; Wang, Yanyan; Zhang, Yafei

2016-08-01

Graphene-based all-solid-state supercapacitors (ASSSCs) are one of the most ideal candidates for high-performance flexible power sources. The achievement of high volumetric energy density is highly desired for practical application of this type of ASSSCs. Here, we present a facile method to boost volumetric performances of graphene-based flexible ASSSCs through incorporation of ultrafine polyaniline-poly(4-styrenesulfonate) (PANI-PSS) nanoparticles in reduced graphene oxide (rGO) papers. A compact structure is obtained via intimate contact and π-π interaction between PANI-PSS nanoparticles and rGO sheets. The hybrid paper electrode with the film thickness of 13.5 μm, shows an extremely high volumetric specific capacitance of 272 F/cm3 (0.37 A/cm3 in a three-electrode cell). The assembled ASSSCs show a large volumetric specific capacitance of 217 F/cm3 (0.37 A/cm3 in a two-electrode cell), high volumetric energy and power density, excellent capacitance stability, small leakage current as well as low self-discharge characteristics, revealing the usefulness of this robust hybrid paper for high-performance flexible energy storage devices.

High-Resolution Magnetic Resonance Imaging Enhanced With Superparamagnetic Nanoparticles Measures Macrophage Burden in Atherosclerosis

PubMed Central

Morishige, Kunio; Kacher, Daniel F.; Libby, Peter; Josephson, Lee; Ganz, Peter; Weissleder, Ralph; Aikawa, Masanori

2010-01-01

Background Macrophages contribute to the progression and acute complications of atherosclerosis. Macrophage imaging may serve as a biomarker to identify subclinical inflamed lesions, to predict future risk, and to aid in the assessment of novel therapies. Methods and Results To test the hypothesis that nanoparticle-enhanced, high-resolution magnetic resonance imaging (MRI) can measure plaque macrophage accumulation, we used 3-T MRI with a macrophage-targeted superparamagnetic nanoparticle preparation (monocrystalline iron oxide nanoparticles-47 [MION-47]) in cholesterol-fed New Zealand White rabbits 6 months after balloon injury. In vivo MRI visualized thickened abdominal aortas on both T1- and T2-weighted spin-echo images (T1 spin echo, 20 axial slices per animal; T2 spin echo, 28 slices per animal). Seventy-two hours after MION-47 injection, aortas exhibited lower T2 signal intensity compared with before contrast imaging (signal intensity ratio, aortic wall/muscle: before, 1.44±0.26 versus after, 0.95±0.22; 164 slices; P<0.01), whereas T1 spin echo images showed no significant change. MRI on ex vivo specimens provided similar results. Histological studies colocalized iron accumulation with immunoreactive macrophages in atheromata. The magnitude of signal intensity reduction on T2 spin echo in vivo images further correlated with macrophage areas in situ (150 slices; r=0.73). Treatment with rosuvastatin for 3 months yielded diminished macrophage content (P<0.05) and reversed T2 signal intensity changes (P<0.005). Signal changes in rosuvastatin-treated rabbits correlated with reduced macrophage burden (r=0.73). In vitro validation studies showed concentration-dependent MION-47 uptake by human primary macrophages. Conclusion The magnitude of T2 signal intensity reduction in high-resolution MRI after administration of superparamagnetic phagocytosable nanoparticles can assess macrophage burden in atheromata, providing a clinically translatable tool to identify

High Resolution Fabrication of Interconnection Lines Using Picosecond Laser and Controlled Deposition of Gold Nanoparticles

NASA Astrophysics Data System (ADS)

Shahmoon, Asaf; Strauß, Johnnes; Zafri, Hadar; Schmidt, Michael; Zalevsky, Zeev

In this paper we present the fabrication procedure as well as the preliminary experimental results of a novel method for construction of high resolution nanometric interconnection lines. The fabrication procedure relies on a self-assembly process of gold nanoparticles at specific predetermined nanostructures. The nanostructures for the self-assembly process are based on the focused ion beam (FIB) or scanning electron beam (SEM) technology. The assembled nanoparticles are being illuminated using a picosecond laser with a wavelength of 532 nm. Different pulse energies have been investigated. The paper aimed at developing a novel and reliable process for fabrication of interconnection lines encompass three different disciplines, self-assembly of nanometric particles, optics and microelectronic.

ZIF-8 immobilized nickel nanoparticles: highly effective catalysts for hydrogen generation from hydrolysis of ammonia borane.

PubMed

Li, Pei-Zhou; Aranishi, Kengo; Xu, Qiang

2012-03-28

Highly dispersed Ni nanoparticles have been successfully immobilized by the zeolitic metal-organic framework ZIF-8 via sequential deposition-reduction methods, which show high catalytic activity and long durability for hydrogen generation from hydrolysis of aqueous ammonia borane (NH(3)BH(3)) at room temperature. This journal is © The Royal Society of Chemistry 2012

Immobilizing Highly Catalytically Active Pt Nanoparticles inside the Pores of Metal-Organic Framework: A Double Solvents Approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aijaz, Arshad; Karkamkar, Abhijeet J.; Choi, Young Joon

2012-08-29

Ultrafine Pt nanoparticles were successfully immobilized inside the pores of a metal-organic framework MIL-101 without deposition of Pt nanoparticles on the external surfaces of framework by using a 'double solvents' method. The resulting Pt@MIL-101 composites with different Pt loadings represent the first highly active MOF-immobilized metal nanocatalysts for catalytic reactions in all three phases: liquid-phase ammonia borane hydrolysis; solid-phase ammonia borane thermal dehy-drogenation and gas-phase CO oxidation. The observed excellent catalytic performances are at-tributed to the small Pt nanoparticles within the pores of MIL-101. 'We are thankful to AIST and METI for financial support. TA & AK are thankful formore » support from the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. PNNL is operated by Battelle.'« less

Physicochemical properties of protein-modified silver nanoparticles in seawater

NASA Astrophysics Data System (ADS)

Zhong, Hangyue

2013-10-01

This study investigated the physicochemical properties of silver nanoparticles stabilized with casein protein in seawater. UV?vis spectrometry, dynamic light scattering (DLS), and transmission electron microscopy (TEM) were applied to measure the stability of silver nanoparticles in seawater samples. The obtained results show an increased aggregation tendency of silver nanoparticles in seawater, which could be attributed its relatively high cation concentration that could neutralize the negatively charges adsorbed on the surface of silver nanoparticles and reduce the electrostatic repulsion forces between nanoparticles. Similarly, due to the surface charge screening process, the zeta potential of silver nanoparticles in seawater decreased. This observation further supported the aggregation behavior of silver nanoparticles. This study also investigated the dissolution of silver nanoparticles in seawater. Result shows that the silver nanoparticle dissolution in DI water is lower than in seawater, which is attributed to the high Cl? concentration present in seawater. As Cl? can react with silver and form soluble AgCl complex, dissolution of silver nanoparticles was enhanced. Finally, this study demonstrated that silver nanoparticles are destabilized in seawater condition. These results may be helpful in understanding the environmental risk of discharged silver nanoparticles in seawater conditions.

High surface area LaMnO3 nanoparticles enhancing electrochemical catalytic activity for rechargeable lithium-air batteries

NASA Astrophysics Data System (ADS)

Li, Chuanhua; Yu, Zhiyong; Liu, Hanxing; Chen, Kang

2018-02-01

To improve sluggish kinetics of ORR and OER (oxygen reduction and evolution reaction) on the air electrode, the high surface area LaMnO3 nanoparticle catalysts were synthesized by sol-gel method. The specific surface area of as-synthesized pure phase LaMnO3 nanoparticles is 21.21 m2 g-1. The onset potential of high surface area LaMnO3 in alkaline solution is -0.0202 V which is comparable to commercial Pt/C. When the assembled high surface area LaMnO3-based lithium-air batteries were measured at 100 mA g-1, the initial discharge specific capacity could reach 6851.9 mA h g-1(carbon). In addition, lithium-oxygen batteries including high surface area LaMnO3 catalysts could be cycled for 52 cycles at 200 mA g-1 under a limited discharge-charge depth of 500 mA h gcarbon-1.

Effects of halloysite nanotubes on physical properties and cytocompatibility of alginate composite hydrogels.

PubMed

Huang, Biao; Liu, Mingxian; Long, Zheru; Shen, Yan; Zhou, Changren

2017-01-01

Sodium alginate (SA)/halloysite nanotubes (HNTs) composite hydrogels were successfully prepared by solution blending and cross-linking with calcium ions. HNTs can improve the physical properties and cytocompatibility of composite hydrogels. The static and shear viscosity of SA/HNTs solution increase by the addition of HNTs. FTIR suggests the presence of hydrogen bond interactions between HNTs and SA. The crystal structure of HNTs is retained in the composites as showed by the X-ray diffraction result. A porous structure with pore size of 100-250μm is found in the hydrogels, which can provide a space for cell growth and migration. The compressive mechanical properties of composite hydrogels significantly increase compared to the pure SA hydrogel. The SA/HNTs composite hydrogels with 80% HNTs loading exhibit the compressive stress at 80% strain of 2.99MPa, while the stress at 80% strain of pure SA hydrogel is only 0.8MPa. The dynamic storage modulus of composite hydrogels also markedly increases with HNTs concentration. The differential scanning calorimetry endothermic peak area and swelling ratios in NaCl solution of the composite hydrogels decrease by the addition of HNTs. Preosteoblast (MC3T3-E1) culture results reveal that the SA/HNTs composites especially at relatively low HNTs loading show a significant increase in cells adhesion and proliferation compared to the pure SA hydrogel. All the results demonstrate that the SA/HNTs composite hydrogels show a promising application in bone tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

Highly efficient enrichment of phosphopeptides from HeLa cells using hollow magnetic macro/mesoporous TiO2 nanoparticles.

PubMed

Hong, Yayun; Zhan, Qiliang; Pu, Chenlu; Sheng, Qianying; Zhao, Hongli; Lan, Minbo

2018-09-01

In this work, hollow magnetic macro/mesoporous TiO 2 nanoparticles (denoted as Fe 3 O 4 @H-fTiO 2 ) were synthesized by a facile "hydrothermal etching assisted crystallization" route to improve the phosphopeptide enrichment efficiency. The porous nanostructure of TiO 2 shell and large hollow space endowed the Fe 3 O 4 @H-fTiO 2 with a high surface area (144.71 m 2 g -1 ) and a large pore volume (0.52 cm 3 g -1 ), which could provide more affinity sites for phosphopeptide enrichment. Besides, the large pore size of TiO 2 nanosheets and large hollow space could effectively prevent the "shadow effect", thereby facilitating the diffusion and release of phosphopeptides. Compared with the hollow magnetic mesoporous TiO 2 with small and deep pores (denoted as Fe 3 O 4 @H-mTiO 2 ) and solid magnetic macro/mesoporous TiO 2 , the Fe 3 O 4 @H-fTiO 2 nanoparticles showed a better selectivity (molar ratio of α-casein/BSA up to 1:10000) and a higher sensitivity (0.2 fmol/μL α-casein) for phosphopeptide enrichment. Furthermore, 1485 unique phosphopeptides derived from 660 phosphoproteins were identified from HeLa cell extracts after enrichment with Fe 3 O 4 @H-fTiO 2 nanoparticles, further demonstrating that the Fe 3 O 4 @H-fTiO 2 nanoparticles had a high-efficiency performance for phosphopeptide enrichment. Taken together, the Fe 3 O 4 @H-fTiO 2 nanoparticles will have unique advantages in phosphoproteomics analysis. Copyright © 2018 Elsevier B.V. All rights reserved.

Nanoparticle engineering of colloidal suspension behavior

NASA Astrophysics Data System (ADS)

Chan, Angel Thanda

We investigate the effects of highly charged nanoparticles on the phase behavior, structure, and assembly of colloidal microsphere suspensions. Specifically, by selectively tuning the electrostatic interactions between silica microspheres and polystyrene nanoparticles, we study the behavior of four key systems: (i) strongly repulsive, (ii) haloing, (iii) weakly attractive, and (iv) strongly attractive systems. In each system, a combination of nanoparticle adsorption, zeta potential, and confocal microscopy measurements are carried out to systematically study the effects of nanoparticle volume fraction, microsphere/nanoparticle size ratios, and interparticle interactions on their behavior. Our observations indicate that minimal adsorption of highly charged nanoparticles occurs on like-charged and negligibly-charged microspheres, whereas their extent of association increases dramatically with increasing microsphere-nanoparticle attraction. A rich phase behavior emerges in these systems based on whether the nanoparticle species serve as depletants, haloing, or bridging species. The phase transitions in the haloing system occur at constant nanoparticle volume fractions, φnano, over a broad range of microsphere volume fractions, φmicro . By contrast, the observed transitions in the weakly and strongly attractive mixtures occur at a constant number ratio of nanoparticles per microsphere, Nnano/Nmicro. Important structural differences emerge, which can be exploited in the assembly of colloidal gels for direct ink writing and colloidal crystals on epitaxially patterned substrates. Finally, for the first time, we explore nanoparticle haloing as a new route for stabilizing hydrophobic colloidal drugs in aqueous suspensions media for preparation of injectable pharmaceuticals. These microsphere suspensions exhibit improved stability relative to their surfactant-stabilized counterparts after autoclaving, a critical processing step for this target applications. This research

From tunable core-shell nanoparticles to plasmonic drawbridges: Active control of nanoparticle optical properties

PubMed Central

Byers, Chad P.; Zhang, Hui; Swearer, Dayne F.; Yorulmaz, Mustafa; Hoener, Benjamin S.; Huang, Da; Hoggard, Anneli; Chang, Wei-Shun; Mulvaney, Paul; Ringe, Emilie; Halas, Naomi J.; Nordlander, Peter; Link, Stephan; Landes, Christy F.

2015-01-01

The optical properties of metallic nanoparticles are highly sensitive to interparticle distance, giving rise to dramatic but frequently irreversible color changes. By electrochemical modification of individual nanoparticles and nanoparticle pairs, we induced equally dramatic, yet reversible, changes in their optical properties. We achieved plasmon tuning by oxidation-reduction chemistry of Ag-AgCl shells on the surfaces of both individual and strongly coupled Au nanoparticle pairs, resulting in extreme but reversible changes in scattering line shape. We demonstrated reversible formation of the charge transfer plasmon mode by switching between capacitive and conductive electronic coupling mechanisms. Dynamic single-particle spectroelectrochemistry also gave an insight into the reaction kinetics and evolution of the charge transfer plasmon mode in an electrochemically tunable structure. Our study represents a highly useful approach to the precise tuning of the morphology of narrow interparticle gaps and will be of value for controlling and activating a range of properties such as extreme plasmon modulation, nanoscopic plasmon switching, and subnanometer tunable gap applications. PMID:26665175

Fabrication of high aspect ratio nanogrid transparent electrodes via capillary assembly of Ag nanoparticles

NASA Astrophysics Data System (ADS)

Kang, Juhoon; Park, Chang-Goo; Lee, Su-Han; Cho, Changsoon; Choi, Dae-Geun; Lee, Jung-Yong

2016-05-01

In this report, we describe the fabrication of periodic Ag nanogrid electrodes by capillary assembly of silver nanoparticles (AgNPs) along patterned nanogrid templates. By assembling the AgNPs into these high-aspect-ratio nanogrid patterns, we can obtain high-aspect-ratio nanogratings, which can overcome the inherent trade-off between the optical transmittance and the sheet resistance of transparent electrodes. The junction resistance between the AgNPs is effectively reduced by photochemical welding and post-annealing. The fabricated high-aspect-ratio nanogrid structure with a line width of 150 nm and a height of 450 nm has a sheet resistance of 15.2 Ω sq-1 and an optical transmittance of 85.4%.In this report, we describe the fabrication of periodic Ag nanogrid electrodes by capillary assembly of silver nanoparticles (AgNPs) along patterned nanogrid templates. By assembling the AgNPs into these high-aspect-ratio nanogrid patterns, we can obtain high-aspect-ratio nanogratings, which can overcome the inherent trade-off between the optical transmittance and the sheet resistance of transparent electrodes. The junction resistance between the AgNPs is effectively reduced by photochemical welding and post-annealing. The fabricated high-aspect-ratio nanogrid structure with a line width of 150 nm and a height of 450 nm has a sheet resistance of 15.2 Ω sq-1 and an optical transmittance of 85.4%. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01896c

Electronically cloaked nanoparticles

NASA Astrophysics Data System (ADS)

Shen, Wenqing

The concept of electronic cloaking is to design objects invisible to conduction electrons. The approach of electronic cloaking has been recently suggested to design invisible nanoparticle dopants with electronic scattering cross section smaller than 1% of the physical cross section (pi a2), and therefore to enhance the carrier mobility of bulk materials. The proposed nanoparticles have core-shell structures. The dopants are incorporated inside the core, while the shell layer serves both as a spacer to separate the charge carriers from their parent atoms and as a cloaking shell to minimize the scattering cross section of the electrons from the ionized nanoparticles. Thermoelectric materials are usually highly doped to have enough carrier density. Using invisible dopants could achieve larger thermoelectric power factors by enhancing the electronic mobility. Core-shell nanoparticles show an advantage over one-layer nanoparticles, which are proposed in three-dimensional modulation doping. However designing such nanoparticles is not easy as there are too many parameters to be considered. This thesis first shows an approach to design hollow nanoparticles by applying constrains on variables. In the second part, a simple mapping approach is introduced where one can identify possible core-shell particles by comparing the dimensionless parameters of chosen materials with provided maps. In both parts of this work, several designs with realistic materials were made and proven to achieve electronic cloaking. Improvement in the thermoelectric power factor compared to the traditional impurity doping method was demonstrated in several cases.

Effect of Pore Size and Porosity on the Biomechanical Properties and Cytocompatibility of Porous NiTi Alloys

PubMed Central

Jian, Yu-Tao; Yang, Yue; Tian, Tian; Stanford, Clark; Zhang, Xin-Ping; Zhao, Ke

2015-01-01

Five types of porous Nickel-Titanium (NiTi) alloy samples of different porosities and pore sizes were fabricated. According to compressive and fracture strengths, three groups of porous NiTi alloy samples underwent further cytocompatibility experiments. Porous NiTi alloys exhibited a lower Young’s modulus (2.0 GPa ~ 0.8 GPa). Both compressive strength (108.8 MPa ~ 56.2 MPa) and fracture strength (64.6 MPa ~ 41.6 MPa) decreased gradually with increasing mean pore size (MPS). Cells grew and spread well on all porous NiTi alloy samples. Cells attached more strongly on control group and blank group than on all porous NiTi alloy samples (p < 0.05). Cell adhesion on porous NiTi alloys was correlated negatively to MPS (277.2 μm ~ 566.5 μm; p < 0.05). More cells proliferated on control group and blank group than on all porous NiTi alloy samples (p < 0.05). Cellular ALP activity on all porous NiTi alloy samples was higher than on control group and blank group (p < 0.05). The porous NiTi alloys with optimized pore size could be a potential orthopedic material. PMID:26047515

Progesterone lipid nanoparticles: Scaling up and in vivo human study.

PubMed

Esposito, Elisabetta; Sguizzato, Maddalena; Drechsler, Markus; Mariani, Paolo; Carducci, Federica; Nastruzzi, Claudio; Cortesi, Rita

2017-10-01

This investigation describes a scaling up study aimed at producing progesterone containing nanoparticles in a pilot scale. Particularly hot homogenization techniques based on ultrasound homogenization or high pressure homogenization have been employed to produce lipid nanoparticles constituted of tristearin or tristearin in association with caprylic-capric triglyceride. It was found that the high pressure homogenization method enabled to obtain nanoparticles without agglomerates and smaller mean diameters with respect to ultrasound homogenization method. X-ray characterization suggested a lamellar structural organization of both type of nanoparticles. Progesterone encapsulation efficiency was almost 100% in the case of high pressure homogenization method. Shelf life study indicated a double fold stability of progesterone when encapsulated in nanoparticles produced by the high pressure homogenization method. Dialysis and Franz cell methods were performed to mimic subcutaneous and skin administration. Nanoparticles constituted of tristearin in mixture with caprylic/capric triglyceride display a slower release of progesterone with respect to nanoparticles constituted of pure tristearin. Franz cell evidenced a higher progesterone skin uptake in the case of pure tristearin nanoparticles. A human in vivo study, based on tape stripping, was conducted to investigate the performance of nanoparticles as progesterone skin delivery systems. Tape stripping results indicated a decrease of progesterone concentration in stratum corneum within six hours, suggesting an interaction between nanoparticle material and skin lipids. Copyright © 2017 Elsevier B.V. All rights reserved.

ZnO nanoparticles based fiber optic gas sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Narasimman, S.; Sivacoumar, R.; Alex, Z. C.

In this work, ZnO nanoparticles were synthesized by simple aqueous chemical route method. The synthesized ZnO nanoparticles were characterized by X-ray diffraction and scanning electron microscope. The sensitivity of the nanoparticles was studied for different gases like acetone, ammonia and ethanol in terms of variation in spectral light intensity. The XRD and SEM analysis confirms the formation of hexagonal wurtzite structure with the grain size of 11.2 nm. The small cladding region of the optical fiber was replaced with the synthesized nanoparticles. The light spectrum was recorded for different gas concentrations. The synthesized nanoparticles showed high sensitivity towards ammonia in lowmore » ppm level and acetone in high ppm level.« less

High Pressure Structure and Electrical Resistance Measurements on Cadmium Sulfide Nanoparticles

NASA Astrophysics Data System (ADS)

Montgomery, J. M.; Stemshorn, A. K.; Stanishevsky, A.; Vohra, Y. K.; Weir, S. T.

2010-03-01

Room-temperature four-probe electrical resistance and synchrotron x-ray diffraction measurements have been performed on dried and aqueous suspensions of CdS nanoparticles (25 nm in diameter) to 35 GPa. Nanoparticles used in these experiments were synthesized using the reaction between a cadmium salt and thiourea under hydrothermal conditions without using any surfactants. While the x-ray structure data confirms the irreversible wurtzite -> rocksalt transition seen at 2.5 GPa in bulk CdS, the corresponding resistance drop was not observed in the measured range, indicating that the nanoparticle boundaries may prevent electronic communication between particles. Further studies on dry and aqueous 10 nm nano-spheres and 9 nm diameter nano-rods are planned, and the results of these experiments will be presented.