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Avinash Kumar Thakur, Motahareh Ghahari Larimi, Kristin Gooden, Liviu Movileanu
There have been only a few studies reporting on the impact of polyhistidine affinity tags on the structure, function, and dynamics of proteins. Because of their relatively short size, they are often assumed to have little or no effect on the conformation and activity of a protein. Here, using membrane protein design and single-molecule electrophysiology, we determined that the presence of a hexahistidine arm at the N-terminus of a truncated FhuA-based protein nanopore, leaving the C-terminus untagged, produces an unusual increase in the unitary conductance up to ~8 nS in 1 M KCl...
August 16, 2017: Biochemistry
Mareike Haensch, Julian Behnken, Luis Balboa, Alexander Dyck, Gunther Wittstock
The extension of the surface interrogation mode of scanning electrochemical microscopy (SI-SECM) is demonstrated for porous electrode materials. These materials are often high surface area powders which are very important electrocatalysts for instance in fuel cells or water electrolyzers. The powdered electrocatalyst material is filled into a cavity-microelectrode which is then operated as the sample electrode in SECM. After a surface oxide generation step, the oxides on the porous sample are reduced by [Ru(NH3)6](2+) formed at the microelectrode probe of the SECM while the sample is at open circuit potential...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
Amy E Chavis, Kyle T Brady, Grace A Hatmaker, Christopher E Angevine, Nuwan Kothalawala, Amala Dass, Joseph W F Robertson, Joseph E Reiner
Sensing and characterization of water-soluble peptides is of critical importance in a wide variety of bioapplications. Single molecule nanopore spectrometry (SMNS) is based on the idea that one can use biological protein nanopores to resolve different sized molecules down to limits set by the blockade duration and noise. Previous work has shown that this enables discrimination between polyethylene glycol (PEG) molecules that differ by a single monomer unit. This paper describes efforts to extend SMNS to a variety of biologically relevant, water-soluble peptides...
August 16, 2017: ACS Sensors
Seokyung Hwang, Wuseok Kim, Heewon Yoon, Sangmin Jeon
A nanoporous polymethylmethacrylate (PMMA) wire was prepared by electrospinning under high humidity and attached between two prongs of a microfabricated quartz tuning fork (QTF). Exposure of the QTF to ethanol vapor caused a frequency shift due to a decrease in the modulus of the PMMA wire, and the frequency change increased as the concentration of ethanol vapor increased. The nanoporous wire-coated QTF exhibited higher sensitivity and faster response time than a plain wire-coated QTF, which was attributed to the high surface area and pore networks facilitating the transport of ethanol molecules inside the PMMA wire...
August 16, 2017: ACS Sensors
Wuttipong Mahakham, Ajit K Sarmah, Santi Maensiri, Piyada Theerakulpisut
Application of nanomaterials for agriculture is relatively new as compared to their use in biomedical and industrial sectors. In order to promote sustainable nanoagriculture, biocompatible silver nanoparticles (AgNPs) have been synthesized through green route using kaffir lime leaf extract for use as nanopriming agent for enhancing seed germination of rice aged seeds. Results of various characterization techniques showed the successful formation of AgNPs which were capped with phytochemicals present in the plant extract...
August 15, 2017: Scientific Reports
Jennifer L Poole, Scott Donahue, David Wilson, Yuk Mun Li, Qi Zhang, Yibei Gu, Rachel Ferebee, Zhao Lu, Rachel Mika Dorin, Lawrence F Hancock, Larry Takiff, Ilhem F Hakem, Michael R Bockstaller, Ulrich Wiesner, Jeremy Walker
The functionalization with phosphotriesterase of poly(isoprene-b-styrene-b-4-vinylpyridine)-based nanoporous membranes fabricated by self-assembly and nonsolvent induced phase separation (SNIPS) is shown to enable dynamically responsive membranes capable of substrate-specific and localized gating response. Integration of the SNIPS process with macroporous nylon support layers yields mechanically robust textile-type films with high moisture vapor transport rates that display rapid and local order-of-magnitude modulation of permeability...
August 15, 2017: Macromolecular Rapid Communications
Yudan Zhu, Yang Ruan, Yumeng Zhang, Yaojia Chen, Xiaohua Lu, Linghong Lu
The separation behaviors of Mg2+ and Li+ were investigated using molecular dynamics. Two functionalized graphene nanopore models (i.e., co_5 and coo_5) inspired by the characteristic structural features of Mg2+ channels were used. Both nanopores exhibited a higher preference to Mg2+ than to Li+, and the selectivity ratios were higher for coo_5 than for co_5 under all the studied transmembrane voltages. An evaluation of the effect of coordination on the ionic hydration microstructures for both nanopores showed that the positioning of the modified groups could better fit a hydrated Mg2+ than a hydrated Li+, as if Mg2+ was not dehydrated according to hydrogen bond analysis of the ionic hydration shells...
August 13, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
George Y Chen, Xuan Wu, Yvonne Qiongyue Kang, Li Yu, Tanya M Monro, David G Lancaster, Xiaokong Liu, Haolan Xu
Real-time measurement of the relative humidity of air has applications ranging from process control to safety. By using a microfiber form-factor, we demonstrate a miniature and fast-response hygrometer with the shortest-ever response time (3 ms). The sensor head consists of an optical microfiber of 10 µm diameter and 2 mm length configured to form a compact U-shaped probe, and functionalized with a polyelectrolyte multilayer coating of 1.0 bilayer. The sensing mechanism is primarily water-absorption-based optical loss...
August 11, 2017: Scientific Reports
Xin Yi, Yuxuan Wu, Guoxin Tan, Peng Yu, Lei Zhou, Zhengnan Zhou, Junqi Chen, Zhengao Wang, Jinshan Pang, Chengyun Ning
Traced dopamine (DA) detection is critical for the early diagnosis and prevention of some diseases such as Parkinson's, Alzheimer and schizophrenia. In this research, a novel self-supporting three dimensional (3D) bicontinuous nanoporous electrochemical biosensor was developed for the detection of dopamine by Differential Pulse Voltammetry (DPV). This biosensor was fabricated by electrodepositing palladium nanoparticles (Pd) onto self-supporting nanoporous gold (NPG) wire. Because of the synergistic effects of the excellent catalytic activity of Pd and novel structure of NPG wire, the palladium nanoparticles decorated NPG (Pd/NPG) biosensor possess tremendous superiority in the detection of DA...
August 11, 2017: Scientific Reports
Ziling Deng, Eric Detsi
Despite its high popularity, chemical dealloying that is widely used for the fabrication of nanoporous metals is a relatively slow process: dealloying a few milligrams of bulk material may take from several hours up to a few days, depending on the material system. Raising the temperature of the corroding medium is a common approach to speed up the dealloying process. However, high temperatures cause undesired ligament growth in dealloyed materials. Here we report for the first time the use of a catalytically driven reaction to speed up the dealloying process at ambient temperature and pressure...
August 11, 2017: Nanoscale
Nagavendra Kommineni, Raju Saka, Wahid Khan, Abraham J Domb
Cardiovascular complications are leading causes of most fatalities. Coronary artery disease and surgical failures contribute to the death of the majority of patients. Advanced research in the field of medical devices like stents has efficiently resolved these problems. Clinically, drug-eluting stents have proven their efficacy and safety compared to bare metal stents, which have problems of in-stent restenosis. However, drug-loaded stents coated with polymers have shown adverse effects related to the stability and deterioration of the polymer coating over time...
August 10, 2017: Drug Delivery and Translational Research
Stepan Demchyshyn, Janina Melanie Roemer, Heiko Groiß, Herwig Heilbrunner, Christoph Ulbricht, Dogukan Apaydin, Anton Böhm, Uta Rütt, Florian Bertram, Günter Hesser, Markus Clark Scharber, Niyazi Serdar Sariciftci, Bert Nickel, Siegfried Bauer, Eric Daniel Głowacki, Martin Kaltenbrunner
Controlling the size and shape of semiconducting nanocrystals advances nanoelectronics and photonics. Quantum-confined, inexpensive, solution-derived metal halide perovskites offer narrowband, color-pure emitters as integral parts of next-generation displays and optoelectronic devices. We use nanoporous silicon and alumina thin films as templates for the growth of perovskite nanocrystallites directly within device-relevant architectures without the use of colloidal stabilization. We find significantly blue-shifted photoluminescence emission by reducing the pore size; normally infrared-emitting materials become visibly red, and green-emitting materials become cyan and blue...
August 2017: Science Advances
Duah Alkam, Thidathip Wongsurawat, Piroon Jenjaroenpun, Skylar Connor, Charlotte Hobbs, Trudy M Wassenaar, Se-Ran Jun, Intawat Nookaew, David Ussery
We present here the complete genome sequences of three mumps virus (MuV) strains isolated from patients who tested positive for the mumps virus during a mumps outbreak in Springdale, AR (USA), in 2016. The virus genomes, sequenced with Oxford Nanopore technology, belong to genotype G and have an average length of 15,342 nucleotides (nt).
August 10, 2017: Genome Announcements
Dengchao Wang, Michael V Mirkin
Coating the inner wall of a quartz nanopipette with a thin layer of carbon yields a nanopore with the tunable surface charge and chemical state for resistive-pulse and rectification sensing. Herein we report the experimental study and modeling of the electron-transfer gated ion transport processes in carbon nanopipettes. The potential of the unbiased carbon layer can be tuned by adding very low (sub-nM) concentrations of redox species to the solution via bipolar electrochemistry. The potential of carbon determines the electrical double layer structure that, in turn, affects the ionic transport processes...
August 11, 2017: Journal of the American Chemical Society
Mubarak Ali, Ishtiaq Ahmed, Patricio Ramirez, Saima Nasir, Javier Cervera, Salvador Mafe, Christof M Niemeyer, Wolfgang Ensinger
We demonstrate experimentally and theoretically a nanofluidic device for the selective recognition of cesium ion by exploiting host-guest interactions inside confined geometry. For this purpose, a host molecule, i.e., the amine-terminated p-tert-butylcalix[4]arene-crown (t-BuC[4]C-NH2), is successfully synthesized and functionalized on the surface of a single conical nanopore fabricated in polyethylene terephthalate (PET) membrane through carbodiimide coupling chemistry. On exposure to cesium cation, the t-BuC[4]C-Cs+ complex is formed through host-guest interaction, leading to the generation of positive fixed charges on the pore surface...
August 10, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Christine Young, Rahul R Salunkhe, Jing Tang, Chi-Chang Hu, Mohammed Shahabuddin, Ekrem Yanmaz, Md Shahriar A Hossain, Jung Ho Kim, Yusuke Yamauchi
Correction for 'Zeolitic imidazolate framework (ZIF-8) derived nanoporous carbon: the effect of carbonization temperature on the supercapacitor performance in an aqueous electrolyte' by Christine Young et al., Phys. Chem. Chem. Phys., 2016, 18, 29308-29315.
August 10, 2017: Physical Chemistry Chemical Physics: PCCP
Jiwook Shim, Shouvik Banerjee, Hu Qiu, Kirby K H Smithe, David Estrada, Julian Bello, Eric Pop, Klaus Schulten, Rashid Bashir
Methylation at the 5-carbon position of the cytosine nucleotide base in DNA has been shown to be a reliable diagnostic biomarker for carcinogenesis. Early detection of methylation and intervention could drastically increase the effectiveness of therapy and reduce the cancer mortality rate. Current methods for detecting methylation involve bisulfite genomic sequencing, which are cumbersome and demand a large sample size of bodily fluids to yield accurate results. Hence, more efficient and cost effective methods are desired...
August 10, 2017: Nanoscale
Fu-Na Meng, Zi-Yuan Li, Yi-Lun Ying, Shao-Chuang Liu, Junji Zhang, Yi-Tao Long
Herein, the structural stability of single azobenzene modified DNA duplexes, including the trans form and cis form, has been examined separately based on their distinguishable unzipping kinetics from the mixture by an α-hemolysin nanopore. Furthermore, the accurate isomerization efficiency between the trans and cis form was obtained with single molecule resolution.
August 10, 2017: Chemical Communications: Chem Comm
Yaping Feng, Weiwei Zhu, Wei Guo, Lei Jiang
Well-developed structure-function relationships in living systems have become inspirations for the design and application of innovative materials. Building artificial nanofluidic systems for energy conversion undergoes three essential steps of structural and functional development with the uptake of separate biological inspirations. This research field started from the mimicking of the bioelectric function of electric eels, wherein a transmembrane ion concentration gradient is converted into ultrastrong electrical impulses via membrane-protein-regulated ion transport...
August 10, 2017: Advanced Materials
Miten Jain, John R Tyson, Matthew Loose, Camilla L C Ip, David A Eccles, Justin O'Grady, Sunir Malla, Richard M Leggett, Ola Wallerman, Hans J Jansen, Vadim Zalunin, Ewan Birney, Bonnie L Brown, Terrance P Snutch, Hugh E Olsen
BACKGROUND: Long-read sequencing is rapidly evolving and reshaping the suite of opportunities for genomic analysis. For the MinION in particular, as both the platform and chemistry develop, the user community requires reference data to set performance expectations and maximally exploit third-generation sequencing. We performed an analysis of MinION data derived from whole genome sequencing of Escherichiacoli K-12 using the R9.0 chemistry, comparing the results with the older R7.3 chemistry...
2017: F1000Research
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