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ACS Nano

Miao Yang, Nifang Zhao, Ying Cui, Weiwei Gao, Qian Zhao, Chao Gao, Hao Bai, Tao Xie
Materials combining lightweight, robust mechanical performances, and multifunctionality are highly desirable for engineering applications. Graphene aerogels have emerged as attractive candidates. Despite recent progresses, the bottleneck remains how to simultaneously achieve both strength and resilience. While multiscale architecture designs may offer a possible route, the difficulty lies in the lack of design guidelines and how to experimentally achieve the necessary structure control over multiple length scales...
June 21, 2017: ACS Nano
Eduard Carbonell-Sanromà, Jeremy Hieulle, Manuel Vilas-Varela, Pedro Brandimarte, Mikel Iraola, Ana Barragán, Jingcheng Li, Mikel Abadía, Martina Corso, Daniel Sanchez-Portal, Diego Peña, Jose Ignacio Pascual
We report on the on-surface synthesis of 7 armchair graphene nanoribbons (7-AGNRs) substituted with nitrile (CN) functional groups. The CN groups are attached to the GNR backbone by modifying the 7-AGNR precursor. While many of these groups survive the on-surface synthesis, the reaction process causes the cleavage of some CN from the ribbon backbone and the on-surface cycloisomerization of few nitriles onto pyridine rings. Scanning Tunneling Spectroscopy and Density Functional Theory reveal that CN groups behave as very efficient n-dopants, significantly downshifting the bands of the ribbon, and introducing deep impurity levels associated to the nitrogen electron lone pairs...
June 21, 2017: ACS Nano
Oscar Y Fajardo, Fernando Bresme, Alexei A Kornyshev, Michael Urbakh
To a greater or lesser extent, most room temperature ionic liquids (RTILs) absorb water from humid air. Penetration of water into the lubricating nanoscale film may affect its equilibrium structure and dynamic properties and thus influence the ability of RTILs as lubricants to reduce friction between solid surfaces. Here we investigate the impact of hydration on lubrication using non-equilibrium molecular dynamics simulations. Water adsorption changes both the ionic liquid molecules orientation and the slip conditions at the solid-liquid interfaces, resulting in a reduced resistance against squeezing-out of the lubricant by an external load...
June 21, 2017: ACS Nano
Ting Wu, Abdullah Alharbi, Kae-Dyi You, Kim Kisslinger, Eric A Stach, Davood Shahrjerdi
Dual-gate field-effect biosensors (bioFETs) with asymmetric gate capacitances were shown to surpass the Nernst limit of 59 mV/pH. However, previous studies have conflicting findings on the effect of the capacitive amplification scheme on the sensor detection limit, which is inversely proportional to the signal-to-noise ratio (SNR). Here, we present a systematic experimental investigation of the SNR using ultra-thin silicon transistors. Our sensors operate at low voltage and feature asymmetric front and back oxide capacitances with asymmetry factors of 1...
June 21, 2017: ACS Nano
Sheng Tong, Christopher A Quinto, Linlin Zhang, Priya Mohindra, Gang Bao
The ability to generate heat under an alternating magnetic field (AMF) makes magnetic iron oxide nanoparticles (MIONs) an ideal heat source for biomedical applications including cancer thermoablative therapy, tissue preservation, and remote control of cell function. However, there is a lack of quantitative understanding of the mechanisms governing heat generation of MIONs, and the optimal nanoparticle size for magnetic fluid heating (MFH) applications. Here, we show that MIONs with large sizes (>20 nm) have a specific absorption rate (SAR) significantly higher than that predicted by the widely used linear theory of MFH...
June 21, 2017: ACS Nano
Makoto Asai, Dan Zhao, Sanat K Kumar
It is now well-accepted that controlling the spatial dispersion of nanoparticles (NPs), which can be achieved by grafting them with polymers of different chain lengths and grafting densities, is central to optimizing the thermomechanical properties of the resulting polymer nanocomposites. In general, there are two methods for creating such polymer-grafted NPs: "grafting to" and "grafting from". The conventional wisdom is that the "grafting from" mechanism, where monomer-sized initiator/functional groups are attached to the surface followed by growing the chains, allows for higher polymer grafting densities and hence a more uniform polymer coverage of the NP surface...
June 21, 2017: ACS Nano
Sara M Wichner, Victor R Mann, Alexander S Powers, Maya A Segal, Mustafa Mir, Jigar N Bandaria, Mark A DeWitt, Xavier Darzacq, Ahmet Yildiz, Bruce E Cohen
Semiconductor quantum dots (QDs) have proven to be superior probes for single-molecule imaging compared to organic or genetically encoded fluorophores, but they are limited by difficulties in protein targeting, their larger size, and on-off blinking. Here, we report compact aqueous CdSe/CdS QDs with significantly improved bioconjugation efficiency and superior single-molecule optical properties. We have synthesized covalent protein labeling ligands (i.e., SNAP tags) that are optimized for nanoparticle use, and QDs functionalized with these ligands label SNAP-tagged proteins ∼10-fold more efficiently than existing SNAP ligands...
June 21, 2017: ACS Nano
Chihyun Park, Jongbeom Na, Minsu Han, Eunkyoung Kim
Silver mirror patterns were formed reversibly on a polystyrene (PS)-patterned electrode to produce gratings through the electrochemical reduction of silver ions. The electrochemical gratings exhibited high transparency (T > 95%), similar to a see-through window, by matching the refractive index of the grating pattern with the surrounding medium. The gratings switch to a diffractive state upon the formation of a mirror pattern (T < 5%) with a high diffraction efficiency up to 40%, providing reversible diffractive gratings...
June 21, 2017: ACS Nano
Santosh Kumar Meena, Claire Goldmann, Douga Nassoko, Mahamadou Seydou, Thomas Marchandier, Simona Moldovan, Ovidiu Ersen, François Ribot, Corinne Chanéac, Clément Sanchez, David Portehault, Frederik Tielens, Marialore Sulpizi
Nanophase segregation of a bicomponent thiol self-assembled monolayer is predicted using atomistic molecular dynamics simulations and experimentally confirmed. The simulations suggest the formation of domains rich in acid-terminated chains, on one hand, and of domains rich in amide-functionalized ethylene glycol oligomers, on the other hand. In particular, within the amide-ethylene glycol oligomers region, a key role is played by the formation of interchain hydrogen bonds. The predicted phase segregation is experimentally confirmed by the synthesis of 35 and 15 nm gold nanoparticles functionalized with several binary mixtures of ligands...
June 21, 2017: ACS Nano
Igor V Krainov, Janina Klier, Alexander P Dmitriev, Svetlana Klyatskaya, Mario Ruben, Wolfgang Wernsdorfer, Igor V Gornyi
We present experimental results and a theoretical model for the gate-controlled spin-valve effect in carbon nanotubes with side-attached single-molecule magnets TbPc2 (Terbium(III) bis-phthalocyanine). These structures show a giant magnetoresistance up to 1000% in experiments on single-wall nanotubes that are tunnel-coupled to the leads. The proposed theoretical model combines the spin-dependent Fano effect with Coulomb blockade and predicts a spin-spin interaction between the TbPc2 molecules, mediated by conducting electrons via the charging effect...
June 21, 2017: ACS Nano
Junwei Sha, Yilun Li, Rodrigo Villegas Salvatierra, Tuo Wang, Pei Dong, Yongsung Ji, Seoung-Ki Lee, Chenhao Zhang, Jibo Zhang, Robert H Smith, Pulickel M Ajayan, Jun Lou, Naiqin Zhao, James M Tour
An automated metal powder three-dimensional (3D) printing method for in situ synthesis of free-standing 3D graphene foams (GFs) was successfully modeled by manually placing a mixture of Ni and sucrose onto a platform and then using a commercial CO2 laser to convert the Ni/sucrose mixture into 3D GFs. The sucrose acted as the solid carbon source for graphene, and the sintered Ni metal acted as the catalyst and template for graphene growth. This simple and efficient method combines powder metallurgy templating with 3D printing techniques and enables direct in situ 3D printing of GFs with no high-temperature furnace or lengthy growth process required...
June 21, 2017: ACS Nano
Sijie Wan, Qi Zhang, Xiaohang Zhou, Dechang Li, Baohua Ji, Lei Jiang, Qunfeng Cheng
Portable and wearable electronics require much more flexible graphene-based electrode with high fatigue life, which could repeatedly bend, fold, or stretch without sacrificing its mechanical properties and electrical conductivity. Herein, a kind of ultrahigh fatigue resistant graphene-based nanocomposite via tungsten disulfide (WS2) nanosheets is synthesized by introducing a synergistic effect with covalently cross-linking inspired by the orderly layered structure and abundant interfacial interactions of nacre...
June 20, 2017: ACS Nano
Sheng-Lin Qiao, Yang Ma, Yi Wang, Yao-Xin Lin, Hong-Wei An, Li-Li Li, Hao Wang
Intracellular construction of nanoaggregates from synthetic molecules to mimic the natural ordered superstructures gains increasing attentions recently. Here we develop an endogenous Stimuli-Induced-Aggregation (eSIA) approach to construct functional nanoaggregates for sensing and monitoring cellular physiological process in situ. We design a series of thermosensitive polymer-peptide conjugates (PPCs), which are capable of constructing nanoaggregates in cells base on their isothermal phase transition property...
June 19, 2017: ACS Nano
Han Xiao, Zhong-Shuai Wu, Long Chen, Feng Zhou, Shuanghao Zheng, Wencai Ren, Hui-Ming Cheng, Xinhe Bao
Rational engineering and simplified fabrication of high-energy micro-supercapacitors (MSCs) using graphene and other 2D nanosheets are of great value for flexible and integrated electronics. In this work, we develop one-step mask-assisted simplified fabrication of high-energy MSCs based on the interdigital hybrid electrode (PG) patterns of stacking high quality phosphorene nanosheets and electrochemically exfoliated graphene in ionic liquid electrolyte (denoted as PG-MSCs). The hybrid PG films with interdigital patterns were directly manufactured by layer-by-layer deposition of phosphorene and graphene nanosheets with the assistance of a customized interdigital mask, and directly transferred onto a flexible substrate...
June 19, 2017: ACS Nano
Shreya Goel, Dalong Ni, Weibo Cai
Radiotherapy has emerged as one of the first lines of treatment in oncology. The past few decades have seen dramatic changes in the delivery of radiation therapy, with dose fractionation and treatment planning being the major focuses of research. Although effective, such empirical approaches are hardly optimal, and instances of patient mortality and tumor relapse are not rare. In this Perspective, we review the emerging technologies for optimization of radiosensitization, hypoxia modulation, and combinatorial therapeutic regimes for improved treatment outcomes in preclinical tumor models, with a focus on nanotechnology-mediated approaches...
June 16, 2017: ACS Nano
Nai-Chang Yeh
No abstract text is available yet for this article.
June 16, 2017: ACS Nano
SoonGweon Hong, Tobias J Moritz, Christopher M Rath, Pramila Tamrakar, Philip Lee, Thomas Krucker, Luke P Lee
While antibiotic resistance is increasing rapidly, drug discovery has proven to be extremely difficult. Antibiotic resistance transforms some bacterial infections into deadly medical conditions. A significant challenge in antibiotic discovery is designing potent molecules that enter Gram-negative bacteria and also avoid active efflux mechanisms. Critical analysis in rational drug design has been hindered by the lack of effective analytical tools to analyze the bacterial membrane permeability of small molecules...
June 16, 2017: ACS Nano
Zhuang Xie, Pavlo Gordiichuk, Qing-Yuan Lin, Brian Meckes, Peng-Cheng Chen, Lin Sun, Jingshan S Du, Jinghan Zhu, Yuan Liu, Vinayak P Dravid, Chad A Mirkin
A high-throughput, solution-based, scanning-probe photochemical nanopatterning approach, which does not require the use of probes with subwavelength apertures, is reported. Specifically, pyramid arrays made from high-refractive-index polymeric materials were constructed and studied as patterning tools in a conventional liquid-phase beam pen lithography experiment. Two versions of the arrays were explored with either metal-coated or metal-free tips. Importantly, light can be channeled through both types of tips and the appropriate solution phase (e...
June 15, 2017: ACS Nano
Luca Guerrini, Eduardo Garcia-Rico, Nicolas Pazos-Perez, Ramon A Alvarez-Puebla
The senses are the physiological mechanisms of perception that enable an organism to interact with the surrounding media. For centuries, humans have utilized these senses in science; vision and olfaction have been used the most extensively in laboratories followed by gustation and somatosensation, whereas audition has only rarely been employed. Most of these applications of senses were developed spontaneously based on the natural behavior of the chemistry of the reactants producing changes in scent, taste, or color...
June 15, 2017: ACS Nano
Rubul Mout, Moumita Ray, Tristan Tay, Kanae Sasaki, Gulen Yesilbag Tonga, Vincent M Rotello
Endosomal entrapment is a key hurdle for most intracellular protein-based therapeutic strategies. We report a general strategy for efficient delivery of proteins to the cytosol through co-engineering of proteins and nanoparticle vehicles. The proteins feature an oligo(glutamate) sequence (E-tag) that binds arginine-functionalized gold nanoparticles, generating hierarchical spherical nanoassemblies. These assemblies fuse with cell membranes, releasing the E-tagged protein directly into the cytosol. Five different proteins with diverse charges, sizes, and functions were effectively delivered into cells, demonstrating the generality of our method...
June 15, 2017: ACS Nano
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