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https://www.readbyqxmd.com/read/29166033/mapping-nanoscale-hotspots-with-single-molecule-emitters-assembled-into-plasmonic-nanocavities-using-dna-origami
#1
Rohit Chikkaraddy, V A Turek, Nuttawut Kongsuwan, Felix Benz, Cloudy Carnegie, Tim Van De Goor, Bart de Nijs, Angela Demetriadou, Ortwin Hess, Ulrich F Keyser, Jeremy J Baumberg
Fabricating nanocavities in which optically-active single quantum emitters are precisely positioned, is crucial for building nanophotonic devices. Here we show that self-assembly based on robust DNA-origami constructs can precisely position single molecules laterally within sub-5nm gaps between plasmonic substrates that support intense optical confinement. By placing single-molecules at the center of a nanocavity, we show modulation of the plasmon cavity resonance before and after bleaching the chromophore, and obtain enhancements of ≥ 4×10(3) with high quantum yield (≥ 50%)...
November 22, 2017: Nano Letters
https://www.readbyqxmd.com/read/29166022/dynamics-of-ompf-trimer-formation-in-the-bacterial-outer-membrane-of-escherichia-coli
#2
Huilin Ma, Aliza Khan, Shikha Nangia
The self-assembly of outer membrane protein F (OmpF) in the outer membrane of Escherichia coli Gram-negative bacteria was studied using multiscale molecular dynamics simulations. To facilitate the long timescale required for protein assembly, coarse-grained parameterization of E. coli outer membrane lipids was first developed. The OmpF monomers formed stable dimers at specific protein-protein interactions sites irrespective of the lipid membrane environment. The dimer intermediate was asymmetric but provided a template to form a symmetric trimer...
November 22, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29166005/self-assembly-of-tetrameric-and-hexameric-terpyridine-based-macrocycles-using-cd-ii-zn-ii-and-fe-ii
#3
Lei Wang, Zhe Zhang, Xin Jiang, Jennifer A Irvin, Changlin Liu, Ming Wang, Xiaopeng Li
The self-assembly behavior of a tritopic 2,2':6',2″-terpyridine (tpy) ligand with Cd(II), Zn(II), and Fe(II) has been exploited herein to generate a series of tetrameric and hexameric macrocycles. The main advantage of using such transition metals with an octahedral coordination geometry is their distinct coordination abilities (e.g., binding strength and reversibility). With the same ligand, this study reveals that the supramolecular structural variation between tetrameric and hexameric macrocycle architectures can be precisely controlled using different metal ions with the same coordination geometry...
November 22, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/29165987/hierarchical-self-assembly-of-a-porphyrin-into-chiral-macroscopic-flowers-with-superhydrophobic-and-enantioselective-property
#4
Hejin Jiang, Li Zhang, Jie Chen, Minghua Liu
Supramolecular self-assembly provides an efficient way to fabricate simple units into various hierarchical nano/microstructures, which could mimic the bio-self-assembly and develop functional materials. Since chiral molecules and chiral nanostructures are widely adopted by biological systems, an introduction of the chiral factor into the self-assembly process will provide better understanding of the biological systems. Here, using a chiral amphiphilic histidine to assist the self-assembly of a porphyrin with four carboxylic acids, we obtained hierarchical chiral nano to micro structures...
November 22, 2017: ACS Nano
https://www.readbyqxmd.com/read/29165872/manganese-dioxide-coated-ws2-fe3-o4-ssio2-nanocomposites-for-ph-responsive-mr-imaging-and-oxygen-elevated-synergetic-therapy
#5
Guangbao Yang, Rui Zhang, Chao Liang, He Zhao, Xuan Yi, Sida Shen, Kai Yang, Liang Cheng, Zhuang Liu
Recently, the development of multifunctional theranostic nanoplatforms to realize tumor-specific imaging and enhanced cancer therapy via responding or modulating the tumor microenvironment (TME) has attracted tremendous interests in the field of nanomedicine. Herein, tungsten disulfide (WS2 ) nanoflakes with their surface adsorbed with iron oxide nanoparticles (IONPs) via self-assembly are coated with silica and then subsequently with manganese dioxide (MnO2 ), on to which polyethylene glycol (PEG) is attached...
November 22, 2017: Small
https://www.readbyqxmd.com/read/29165453/structural-and-electronic-properties-of-barbituric-acid-and-melamine-containing-ribonucleosides-as-plausible-components-of-prebiotic-rna-implications-for-prebiotic-self-assembly
#6
Sarabjeet Kaur, Purshotam Sharma, Stacey D Wetmore
The RNA world hypothesis assumes that RNA was the first informational polymer that originated from prebiotic chemical soup. However, since the reaction of d-ribose with canonical nucleobases (A, C, G and U) fails to yield ribonucleosides (rNs) in substantial amounts, the spontaneous origin of rNs and the subsequent synthesis of RNA remains an unsolved mystery. To this end, it has been suggested that RNA may have evolved from primitive genetic material (preRNA) composed of simpler prebiotic heterocycles that spontaneously form glycosidic bonds with ribose...
November 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29165062/recent-progress-of-crosslinking-strategies-for-polymeric-micelles-with-enhanced-drug-delivery-in-cancer-therapy
#7
Wei Fan, Luye Zhang, Yiwen Li, Haoxing Wu
The drug delivery by versatile types of self-assembled micelles for tumor treatment, which improved the diagnostic and therapeutic effectiveness, is advocated. However, despite the numerous advantages, applications of most micelle system have been retarded by low in vivo bio-stability which led to premature drug release and nonspecific tissue accumulation. To date, a range of chemistries has been introduced in intermolecular non-covalent/covalent crosslinking strategies for these dynamic nanostructures to produce robust functional nanoparticles with enhanced circulation stability and lower non-targeted organ toxicity...
November 20, 2017: Current Medicinal Chemistry
https://www.readbyqxmd.com/read/29164866/electrochemical-analysis-of-enzyme-based-on-the-self-assembly-of-lipid-bilayer-on-an-electrode-surface-mediated-by-hydrazone-chemistry
#8
Juan Zhang, Xiaonan Wang, Tingjun Chen, Chang Feng, Genxi Li
In this work, a new strategy for electrochemical analysis of enzyme has been proposed based on a self-assembled lipid bilayer on an electrode surface mediated by hydrazone chemistry. Taking aldolase as an example, the enzyme can catalyze the formation of products containing carbonyl groups. These groups can react with hydrazine groups of the functional lipid derivative, resulting in the self-assembly of lipid bilayer on a guanidinium modified electrode surface. The lipid bilayer will then prevent the movement of hydrophilic electrochemical probes...
November 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29164771/functional-self-assembled-peptide-scaffold-inhibits-tnf-alpha-induced-inflammation-and-apoptosis-in-nucleus-pulposus-cells-by-suppressing-nf-%C3%AE%C2%BAb-signaling
#9
Xiaochuan Li, Shi Cheng, Yaohong Wu, Jingwei Ying, Chaofeng Wang, Tianyong Wen, Xuedong Bai, Wei Ji, Deli Wang, Dike Ruan
Although nucleus pulposus (NP) tissue engineering has achieved tremendous success, researches still face the huge obstacles in maintaining cell survival and function. A novel functional self-assembled peptide RADA-KPSS was constructed by conjugating BMP-7 short active fragment (KPSS) to the C-terminus of RADA16-I that displays anti-inflammatory and anti-apoptosis effects. However, whether this functional self-assembled RADA-KPSS peptide can alleviate inflammation and NPC apoptosis induced by TNF-α has not been studied...
November 22, 2017: Journal of Biomedical Materials Research. Part A
https://www.readbyqxmd.com/read/29164227/self-assembled-monolayer-field-effect-transistors-based-on-oligo-9-9-dioctylfluorene-phosphonic-acids
#10
Bastian Gothe, Tjaard de Roo, Johannes Will, Tobias Unruh, Stefan Mecking, Marcus Halik
The use of functional oligomers of π-conjugated oligofluorenes led to a region-selective assembly of amorphous monolayers which exhibit robust lateral charge transport pathways in self-assembled monolayer field-effect transistors over long distances and even in mixed monolayers of semiconducting and insulating molecules. This oligomer concept might stimulate a new molecular design of self-assembling semiconducting materials.
November 22, 2017: Nanoscale
https://www.readbyqxmd.com/read/29164197/theoretical-study-of-the-photothermal-behaviour-of-self-assembled-magnetic-plasmonic-chain-structures
#11
Kai Liu, Amir Mokhtare, Xiaozheng Xue, Edward P Furlani
We study the field-directed self-assembly and photothermal behavior of one-dimensional (1D) chains of core-shell Fe3O4@Au magnetic-plasmonic nanoparticles. Monte Carlo analysis is used to predict the self-assembly of the nanoparticles when they are subjected to a uniform magnetic field and confined to a fluidic nanochannel. A coupled photonic and thermodynamic analysis is performed to analyze the optical and photothermal properties of the 1D chain structures. We show for the first time that the assembled chain structures exhibit a pronounced dip in their absorption spectrum at a wavelength that is strongly sensitive to changes in the refractive index of the surrounding medium...
November 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29164193/two-step-kinetic-model-of-the-self-assembly-mechanism-for-diphenylalanine-micro-nanotube-formation
#12
M S Ishikawa, C Busch, M Motzkus, H Martinho, T Buckup
Peptide nanostructures compose a new class of materials that have gained attention due to their interesting properties. Among them, nanotubes of diphenylalanine (FF) and its analogues have been one of the most studied structures in the last few years. Their importance originates from the need to better understand the formation of β-amyloid fibrils which are associated with Alzheimer's disease. In this work, the FF self-assembly process was probed using time-resolved Raman microscopy. The changes in the Raman spectra are followed over time after injecting water into a FF-film until micro/nanotubes (MNTs) are formed...
November 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29164186/phenylalanine-and-derivatives-as-versatile-low-molecular-weight-gelators-design-structure-and-tailored-function
#13
REVIEW
Tanmay Das, Marleen Häring, Debasish Haldar, David Díaz Díaz
Phenylalanine (Phe) is an essential amino acid classified as neutral and nonpolar due to the hydrophobic nature of the benzyl side chain. In the field of materials science, the chemical modification of phenylalanine at C or N terminus has enabled to synthesize a large number of low-molecular-weight gelators over the past decade. Thus, many physical (or supramolecular) softgel materials have been fabricated by self-assembly of Phe-derived building blocks, which can be programmed with atomic level information and modification...
November 22, 2017: Biomaterials Science
https://www.readbyqxmd.com/read/29163910/cholesterol-directed-nanoparticle-assemblies-based-on-single-amino-acid-peptide-mutations-activate-cellular-uptake-and-decrease-tumor-volume
#14
Shang Li, Rongfeng Zou, Yaoquan Tu, Junchen Wu, Markita P Landry
Peptide drugs have been difficult to translate into effective therapies due to their low in vivo stability. Here, we report a strategy to develop peptide-based therapeutic nanoparticles by screening a peptide library differing by single-site amino acid mutations of lysine-modified cholesterol. Certain cholesterol-modified peptides are found to promote and stabilize peptide α-helix formation, resulting in selectively cell-permeable peptides. One cholesterol-modified peptide self-assembles into stable nanoparticles with considerable α-helix propensity stabilized by intermolecular van der Waals interactions between inter-peptide cholesterol molecules, and shows 68...
November 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/29161325/the-mechanisms-of-humic-substances-self-assembly-with-biological-molecules-the-case-study-of-the-prion-protein
#15
Gabriele Giachin, Ridvan Nepravishta, Walter Mandaliti, Sonia Melino, Alja Margon, Denis Scaini, Pierluigi Mazzei, Alessandro Piccolo, Giuseppe Legname, Maurizio Paci, Liviana Leita
Humic substances (HS) are the largest constituent of soil organic matter and are considered as a key component of the terrestrial ecosystem. HS may facilitate the transport of organic and inorganic molecules, as well as the sorption interactions with environmentally relevant proteins such as prions. Prions enter the environment through shedding from live hosts, facilitating a sustained incidence of animal prion diseases such as Chronic Wasting Disease and scrapie in cervid and ovine populations, respectively...
2017: PloS One
https://www.readbyqxmd.com/read/29160874/biofilm-dispersal-using-nitric-oxide-loaded-nanoparticles-fabricated-by-photo-pisa-influence-of-morphology
#16
Zahra Sadrearhami, Jonathan Yeow, Thuy-Khanh Nguyen, Kitty K K Ho, Naresh Kumar, Cyrille Boyer
Polymeric nanoparticles (NPs) of different morphologies (spheres and worms) were synthesized using a visible light mediated polymerization-induced self-assembly (PISA) approach. Spherical and worm-like NPs were subsequently modified to generate diazeniumdiolate functionalized NPs. Interestingly, the NO release rate and the dispersal of biofilms were found to strongly depend on the NP morphology. NPs with a higher aspect ratio (worms) exhibited a slower NO release rate and greater biofilm dispersal after 1 h of incubation...
November 21, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29160860/self-assembled-inas-nanowires-as-optical-reflectors
#17
Francesco Floris, Lucia Fornasari, Andrea Marini, Vittorio Bellani, Francesco Banfi, Stefano Roddaro, Daniele Ercolani, Mirko Rocci, Fabio Beltram, Marco Cecchini, Lucia Sorba, Francesco Rossella
Subwavelength nanostructured surfaces are realized with self-assembled vertically-aligned InAs nanowires, and their functionalities as optical reflectors are investigated. In our system, polarization-resolved specular reflectance displays strong modulations as a function of incident photon energy and angle. An effective-medium model allows one to rationalize the experimental findings in the long wavelength regime, whereas numerical simulations fully reproduce the experimental outcomes in the entire frequency range...
November 21, 2017: Nanomaterials
https://www.readbyqxmd.com/read/29160851/development-of-an-impedimetric-aptasensor-for-the-detection-of-staphylococcus-aureus
#18
Peggy Reich, Regina Stoltenburg, Beate Strehlitz, Dieter Frense, Dieter Beckmann
In combination with electrochemical impedance spectroscopy, aptamer-based biosensors are a powerful tool for fast analytical devices. Herein, we present an impedimetric aptasensor for the detection of the human pathogen Staphylococcus aureus. The used aptamer targets protein A, a surface bound virulence factor of S. aureus. The thiol-modified protein A-binding aptamer was co-immobilized with 6-mercapto-1-hexanol onto gold electrodes by self-assembly. Optimization of the ratio of aptamer to 6-mercapto-1-hexanol resulted in an average density of 1...
November 21, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29160771/synthesis-of-oxide-free-aluminum-nanoparticles-for-application-to-conductive-film
#19
Yung Jong Lee, Changsoo Lee, Hyuck Mo Lee
Aluminum nanoparticles are considered promising as alternatives to conventional ink materials, replacing silver and copper nanoparticles due to their extremely low cost and low melting temperature. However, a serious obstacle to realizing their use as conductive ink materials is the oxidation of aluminum. In this research, we synthesized the oxide-free aluminum nanoparticles using catalytic decomposition and an oleic acid coating method, and these materials were applied to the conductive ink for the first time...
November 21, 2017: Nanotechnology
https://www.readbyqxmd.com/read/29160710/evaporation-dynamics-of-mixed-nanocolloidal-sessile-droplets
#20
Binita Pathak, Sandeep Hatte, Saptarshi Basu
Evaporation dynamics of a particle laden droplet has been a topic of interest in recent times due to its widespread applications, ranging from surface patterning to drug delivery systems. The interplay of evaporation induced internal flow dynamics, contact line dynamics and nanoparticle self-assembly govern the morphologies of the residual structures. Fine tuning of these residual structures is thus possible by controlling the governing parameters. A nanoparticle laden sessile droplet placed on a hydrophobic substrate undergoes buckling phenomenon which results in a dome-like structure with cavity on the surface...
November 21, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
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