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https://www.readbyqxmd.com/read/28934609/quantitative-measurement-of-sodium-polystyrene-sulfonate-adsorption-onto-ctab-capped-gold-nanoparticles-reveals-hard-and-soft-coronas
#1
Celina M Harris, Savannah G Miller, Kurt Andresen, Lucas B Thompson
Accumulated evidence indicates that nanoparticle behavior in complex biological environments strongly depends on the nanoparticles' surface chemistry. A common way to modify nanoparticles is to deposit oppositely charged molecules on the surfaces in a Layer-by-Layer fashion to build up thin films of polymers. While this polymer coating is a well-developed technique, the quantification of polymers deposited and physical mechanism of polymer deposition remain relatively unstudied. In this work CTAB capped gold nanoparticles, synthesized in a flow reactor, are coated with sodium polystyrene sulfonate and purified through a series of equilibrium dialysis steps...
September 9, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28934114/antimicrobial-nanomaterials-why-evolution-matters
#2
Joseph L Graves, Misty Thomas, Jude Akamu Ewunkem
Due to the widespread occurrence of multidrug resistant microbes there is increasing interest in the use of novel nanostructured materials as antimicrobials. Specifically, metallic nanoparticles such as silver, copper, and gold have been deployed due to the multiple impacts they have on bacterial physiology. From this, many have concluded that such nanomaterials represent steep obstacles against the evolution of resistance. However, we have already shown that this view is fallacious. For this reason, the significance of our initial experiments are beginning to be recognized in the antimicrobial effects of nanomaterials literature...
September 21, 2017: Nanomaterials
https://www.readbyqxmd.com/read/28933793/contribution-of-gold-nanoparticles-to-the-catalytic-dna-strand-displacement-in-leakage-reduction-and-signal-amplification
#3
Bei Wang, Xiang Zhou, Dongbao Yao, Xianbao Sun, Miao He, Xiaojing Wang, Xue Yin, Haojun Liang
A new model using a gold nanoparticle (AuNP)-DNA system to constrain leakage and improve efficiency of catalytic toehold-mediated strand displacement reactions was outlined. A 10-bp spacer on AuNPs and fourfold amount of fuels were determined for good performance of this model with an optimized toehold strategy. After the reaction at 25 °C for 10 h, a 258 pM target could be identified, which is a remarkable improvement compared with the traditional AuNP-DNA system without fuel. Moreover, this model was also studied to differentiate specific single nucleotide polymorphism on target with superior selection factors...
September 21, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28933556/the-assembly-behavior-of-organically-interlinked-gold-nanoparticle-composite-films-a-quartz-crystal-microbalance-investigation
#4
Yelyena Daskal, Tina Tauchnitz, Frederic Güth, Rosemarie Dittrich, Yvonne Joseph
Thin films based on dodecylamine stabilized gold nanoparticles interlinked with different organic molecules are prepared by automatic layer-by-layer self-assembly in a microfluidic quartz crystal microbalance (QCM) cell, to obtain an in-situ insight on the film formation by ligand/linker exchange reactions. The influence of interlinking functional groups and the length of the organic linker molecule on assembly behavior is investigated. Namely alkyldithiols with different lengths are compared to alkyldiamines and alkylbisdithiocarbamates with a C8 alkylic molecular backbone...
September 21, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28933537/membrane-fluidity-sensing-on-the-single-virus-particle-level-with-plasmonic-nanoparticle-transducers
#5
Amin Feizpour, David N Stelter, Crystal Wong, Hisashi Akiyama, Suryaram Gummuluru, Tom Keyes, Bjoern M Reinhard
Viral membranes are nanomaterials whose fluidity depends on their composition, in particular the cholesterol (chol) content. As differences in the membrane composition of individual virus particles can lead to different intracellular fates, biophysical tools capable of sensing the membrane fluidity on the single-virus level are required. In this manuscript, we demonstrate that fluctuations in the polarization of light scattered off gold or silver nanoparticle (NP)-labeled virus-like-particles (VLPs) encode information about the membrane fluidity of individual VLPs...
September 21, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28933351/dosimetric-effects-of-polyethylene-glycol-surface-coatings-on-gold-nanoparticle-radiosensitization
#6
Brandon Koger, Charles Kirkby
One of the main appeals of using gold nanoparticles (GNPs) as radiosensitizers is that their surface coatings can be altered to manipulate their pharmacokinetic properties. However, Monte Carlo studies of GNP dosimetry tend to neglect these coatings, potentially changing the dosimetric results. This study quantifies the dosimetric effects of including a polyethylene glycol (PEG) surface coating on GNPs over both nanoscopic and microscopic ranges. Two dosimetric scales were explored using PENELOPE Monte Carlo simulations...
September 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28933301/cysteine-rich-proteins-for-drug-delivery-and-diagnosis
#7
Guang Yang, Yue Lu, Hunter N Bomba, Zhen Gu
An emerging focus in nanomedicine is the exploration of multifunctional nanocomposite materials that integrate stimuli-responsive, therapeutic, and/or diagnostic functions. In this effort, cysteine-rich proteins have drawn considerable attention as a versatile platform due to their good biodegradability, biocompatibility, and ease of chemical modification. This review surveys cysteine-rich protein-based biomedical materials, including protein-metal nanohybrids, gold nanoparticle-protein agglomerates, protein-based nanoparticles, and hydrogels, with an emphasis on their preparation methods, especially those based on the cysteine residue-related reactions...
September 20, 2017: Current Medicinal Chemistry
https://www.readbyqxmd.com/read/28933144/a-colorimetric-sensor-array-based-on-gold-nanoparticles-with-diverse-surface-charges-for-microorganisms-identification
#8
Bingyu Li, Xizhe Li, Yanhua Dong, Bing Wang, Dongyang Li, Youmin Shi, Yayan Wu
We report a simple and novel colorimetric sensor array for rapid identification of microorganisms. In this study, four gold nanoparticles (AuNPs) with diverse surface charges were used as sensing elements. The interactions between AuNPs and microorganisms led to obvious color shifts, which could be observed by naked eyes. Fifteen microorganisms had their own response patterns and were differentiated by linear discriminant analysis (LDA) successfully. Moreover, microorganisms mixtures could also be well discerned...
September 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28932840/monitoring-plasmon-coupling-and-sers-enhancement-through-in-situ-nanoparticle-spacing-modulation
#9
L Velleman, L Scarabelli, D Sikdar, A A Kornyshev, L M Liz-Marzán, J B Edel
Self-assembled nanoparticle (NP) arrays at liquid interfaces provide a unique optical response which has opened the door to new tuneable metamaterials for sensing and optical applications. NPs can spontaneously assemble at a liquid-liquid interface, forming an ordered, self-healing, low-defect 2D film. The close proximity of the NPs at the interface results in collective plasmonic modes with a spectral response dependent on the distance between the NPs and induces large field enhancements within the gaps. In this study, we assembled spherical and rod-shaped gold NPs with the aim of improving our understanding of NP assembly processes at liquid interfaces, working towards finely controlling their structure and producing tailored optical and enhanced Raman signals...
September 21, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28929951/the-fate-of-inhaled-nanoparticles-detection-and-measurement-by-enhanced-dark-field-microscopy
#10
Robert R Mercer, James F Scabilloni, Liying Wang, Lori A Battelli, James M Antonini, Jenny R Roberts, Yong Qian, Jennifer D Sisler, Vincent Castranova, Dale W Porter, Ann F Hubbs
Assessing the potential health risks for newly developed nanoparticles poses a significant challenge. Nanometer-sized particles are not generally detectable with the light microscope. Electron microscopy typically requires high-level doses, above the physiologic range, for particle examination in tissues. Enhanced dark-field microscopy (EDM) is an adaption of the light microscope that images scattered light. Nanoparticles scatter light with high efficiency while normal tissues do not. EDM has the potential to identify the critical target sites for nanoparticle deposition and injury in the lungs and other organs...
January 1, 2017: Toxicologic Pathology
https://www.readbyqxmd.com/read/28929152/size-dependent-targeted-delivery-of-gold-nanoparticles-modified-with-the-il-6r-specific-aptamer-air-3a-to-il-6r-carrying-cells
#11
Lisa Prisner, Nadine Bohn, Ulrich Hahn, Alf Mews
The delivery of gold nanoparticles (AuNPs) to specific cells strongly depends on the properties e.g. the size of the particles and is of great interest for a large variety of biomedical applications. Here we investigated the size dependence of the receptor-ligand mediated AuNP delivery to cells by comparing very small "molecular" Au-clusters of only 2 nm to larger 7 nm and 36 nm AuNPs with a distinct surface plasmon resonance. Since the molecular weight in this range changes by almost three orders of magnitude, we show how the amount of gold relates to the number of delivered AuNPs...
September 20, 2017: Nanoscale
https://www.readbyqxmd.com/read/28927538/advances-in-ligase-chain-reaction-and-ligation-based-amplifications-for-genotyping-assays-detection-and-applications
#12
REVIEW
Abdullah A Gibriel, Ola Adel
Genetic variants have been reported to cause several genetic diseases. Various genotyping assays have been developed for diagnostic and screening purposes but with certain limitations in sensitivity, specificity, cost effectiveness and/or time savings. Since the discovery of ligase chain reaction (LCR) in the late nineties, it became one of the most favored platforms for detecting these variants and also for genotyping low abundant contaminants. Recent and powerful modifications with the integration of various detection strategies such as electrochemical and magnetic biosensors, nanoparticles (NPs), quantum dots, quartz crystal and leaky surface acoustic surface biosensors, DNAzyme, rolling circle amplification (RCA), strand displacement amplification (SDA), surface enhanced raman scattering (SERS), chemiluminescence and fluorescence resonance energy transfer have been introduced to both LCR and ligation based amplifications to enable high-throughput and inexpensive multiplex genotyping with improved robustness, simplicity, sensitivity and specificity...
July 2017: Mutation Research
https://www.readbyqxmd.com/read/28927194/finding-a-facile-way-for-the-bacterial-dna-transformation-by-biosynthesized-gold-nanoparticles
#13
Madhuree Kumari, Shipra Pandey, Aradhana Mishra, Chandra Shekhar Nautiyal
The major problem encountered during genetic manipulation of bacteria is the inability to get transformed because of their natural non-competency. In this study, to overcome this problem, a cost-effective method was developed by combining the properties of gold nanoparticles (GNPs) and the Yoshida effect. Various parameters, including GNP:plasmid ratio, pH and time, were optimized for stability of the GNP-plasmid conjugate. With non-competent Gram-negative cells, the efficiency ranged between 0.1 and 0.45 × 104 transformants μg-1, while the range was (0...
July 3, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28927005/mediatorless-impedance-studies-with-titanium-dioxide-conjugated-gold-nanoparticles-for-hydrogen-peroxide-detection
#14
Nur Hamidah Abdul Halim, Yook Heng Lee, Radha Swathe Priya Malon Marugan, Uda Hashim
An impedimetric-based biosensor constructed using gold nanoparticles (AuNP) entrapped within titanium dioxide (TiO₂) particles for hydrogen peroxide (H₂O₂) detection is the main feature of this research. The matrix of the biosensor employed the surface of TiO₂, which was previously modified with an amine terminal group using 3-Aminopropyltriethoxysilane (APTS) at a low temperature to create a ready to immobilise surface for the biosensor application. Hemoglobin (Hb), which exhibits peroxidase-like activity, was used as the bioreceptor in the biosensor to detect H₂O₂ in solution...
September 18, 2017: Biosensors
https://www.readbyqxmd.com/read/28926064/quantitative-sers-by-hot-spot-normalization-surface-enhanced-rayleigh-band-intensity-as-an-alternative-evaluation-parameter-for-sers-substrate-performance
#15
Haoran Wei, Alexis McCarthy, Junyeob Song, Wei Zhou, Peter J Vikesland
The performance of surface-enhanced Raman spectroscopy (SERS) substrates is typically evaluated by calculating an enhancement factor (EF). However, it is challenging to accurately calculate EF values since the calculation often requires the use of model analytes and requires assumptions about the number of analyte molecules within the laser excitation volume. Furthermore, the measured EF values are target analyte dependent and thus it is challenging to compare substrates with EF values obtained using different analytes...
September 19, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28925683/3d-nanostructured-palladium-functionalized-graphene-aerogel-supported-fe3o4-for-enhanced-ru-bpy-32-based-electrochemiluminescent-immunosensing-of-prostate-specific-antigen
#16
Lei Yang, Yueyuan Li, Yong Zhang, Dawei Fan, Xuehui Pang, Qin Wei, Bin Du
We developed a novel Ru(bpy)32+-based electrochemiluminescence (ECL) immunosensor utilizing palladium nanoparticles (Pd NPs) functionalized graphene aerogel supported Fe3O4 (FGA-Pd) for real sample analysis of prostate specific antigen (PSA). 3D nanostructured FGA-Pd, as a novel ECL carrier, was prepared by in situ reduction. Large amounts of Ru(bpy)32+ could combine with FGA-Pd via electrostatic interaction to establish a brand-new ECL emitter (Ru@FGA-Pd) for improving ECL efficiency. The obtained Ru@FGA-Pd composite was utilized to label the secondary antibody, which generated strong ECL signals with tripropylamine (TPrA) as coreactant...
September 19, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28925256/catalytic-activity-of-peptide-nanoparticle-conjugates-regulated-by-a-conformational-change
#17
Dorian Jamal Mikolajczak, Jason Lee Heier, Boris Schade, Beate Koksch
Herein, we present the design and synthesis of a catalytically active peptide-nanoparticle conjugate whose activity is regulated by a defined conformational change in the self-assembled peptide monolayer. A catalytically active peptide, designed after the heterodimeric α-helical coiled-coil principle was immobilized onto gold nanoparticles and kinetic studies were performed according to the Michaelis-Menten model. The formed peptide monolayer at the gold nanoparticle surface accelerated p nitrophenylacetate (pNPA) hydrolysis by one order of magnitude compared to the soluble peptide while exhibiting no defined secondary structure as determined by infrared (IR) and circular dichroism (CD) spectroscopy...
September 19, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28924717/the-preparation-of-au-tio2-yolk-shell-nanostructure-and-its-applications-for-degradation-and-detection-of-methylene-blue
#18
Gengping Wan, Xiange Peng, Min Zeng, Lei Yu, Kan Wang, Xinyue Li, Guizhen Wang
This paper reports the synthesis of a new type of Au@TiO2 yolk-shell nanostructures by integrating ion sputtering method with atomic layer deposition (ALD) technique and its applications as visible light-driven photocatalyst and surface-enhanced Raman spectroscopy (SERS) substrate. Both the size and amount of gold nanoparticles confined in TiO2 nanotubes could be facilely controlled via properly adjusting the sputtering time. The unique structure and morphology of the resulting Au@TiO2 samples were investigated by using various spectroscopic and microscopic techniques in detail...
September 18, 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28923475/chemical-and-nano-mineralogical-study-for-determining-potential-uses-of-legal-colombian-gold-mine-sludge-experimental-evidence
#19
Nazly E Sánchez-Peña, José L Narváez-Semanate, Daniela Pabón-Patiño, Javier E Fernández-Mera, Marcos L S Oliveira, Kátia da Boit, Bernardo F Tutikian, Tito J Crissien, Diana C Pinto, Iván D Serrano, Claudia I Ayala, Ana L Duarte, José D Ruiz, Luis F O Silva
The present study is focused on the chemical and nano-mineralogical characterization of sludge from gold mine activities, in order to put forward diverse solution alternatives, where lack of knowledge has been found. The sample was collected from "La Estrella" mine of Suarez, located in Department of Cauca, south-west Colombia. The sludge micro-structure and chemical composition were analyzed using a high resolution transmission electron microscopy (HR-TEM) equipped with a dispersive X-ray detector (EDS). X-ray diffraction technique was employed to identify the mineralogical phases present in the sludge...
August 26, 2017: Chemosphere
https://www.readbyqxmd.com/read/28923311/colorimetric-detection-of-d-dimer-in-a-paper-based-immunodetection-device
#20
Sónia Ruivo, Ana M Azevedo, Duarte M F Prazeres
A microfluidic paper-based analytical device (μPADs) immunoassay for detection of the blood native biomarker D-dimer is reported. The μPAD is created by wax printing on a single piece of chromatographic paper and combined with an anti-D-dimer capture antibody and conjugates of anti-D-dimer antibody with 40 nm gold nanoparticles. The presence of D-dimer in buffer/simulated plasma samples is successfully reported for concentrations as low as 15 ng D-dimer/mL. Linearity between signal intensity and D-dimer concentration is observed up to 100 ng/mL...
September 15, 2017: Analytical Biochemistry
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