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https://www.readbyqxmd.com/read/28926954/evidence-for-complex-formation-of-the-bacillus-cereus-haemolysin-bl-components-in-solution
#1
Franziska Tausch, Richard Dietrich, Kristina Schauer, Robert Janowski, Dierk Niessing, Erwin Märtlbauer, Nadja Jessberger
Haemolysin BL is an important virulence factor regarding the diarrheal type of food poisoning caused by Bacillus cereus. However, the pathogenic importance of this three-component enterotoxin is difficult to access, as nearly all natural B. cereus culture supernatants additionally contain the highly cytotoxic Nhe, the second three-component toxin involved in the aetiology of B. cereus-induced food-borne diseases. To better address the toxic properties of the Hbl complex, a system for overexpression and purification of functional, cytotoxic, recombinant (r)Hbl components L₂, L₁ and B from E...
September 16, 2017: Toxins
https://www.readbyqxmd.com/read/28926275/mapping-photoemission-and-hot-electron-emission-from-plasmonic-nanoantennas
#2
Richard Hobbs, William Putnam, Arya Fallahi, Yujia Yang, Franz Kaertner, Karl K Berggren
Understanding plasmon-mediated electron emission and energy transfer on the nanometer length scale is critical to controlling light-matter interactions at nanoscale dimensions. In a high-resolution lithographic material, electron emission and energy transfer lead to chemical transformations. In this work, we employ such chemical transformations in two different high-resolution electron-beam lithography resists, poly(methyl methacrylate) (PMMA) and hydrogen silsesquioxane (HSQ), to map local electron emission and energy transfer with nanometer resolution from plasmonic nanoantennas excited by femtosecond laser pulses...
September 19, 2017: Nano Letters
https://www.readbyqxmd.com/read/28926243/are-we-there-yet-applying-thermodynamic-and-kinetic-profiling-on-embryonic-ectoderm-development-eed-hit-to-lead-program
#3
Ying Wang, Rohinton P Edalji, Sanjay C Panchal, Chaohong C Sun, Stevan W Djuric, Anil Vasudevan
It is advocated that kinetic and thermodynamic profiling of bioactive compounds should be incorporated and utilized as complementary tools for hit and lead optimizations in drug discovery. To assess their applications in the EED hit-to-lead optimization process, large amount of thermodynamic and kinetic data were collected and analyzed via isothermal titration calorimetry (ITC) and surface plasmon resonance (SPR), respectively. Slower dissociation rates (koff) of the lead compounds were observed as the program progressed...
September 19, 2017: Journal of Medicinal Chemistry
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
#4
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/28925710/highly-localized-strain-in-a-mos2-au-heterostructure-revealed-by-tip-enhanced-raman-spectroscopy
#5
Mahfujur Rahaman, Raul D Rodriguez, Gerd Plechinger, Stefan Moras, Christian Schüller, Tobias Korn, Dietrich R T Zahn
Tip-enhanced Raman spectroscopy (TERS) has been rapidly improved over the last decade and opened up opportunities to study phonon properties of materials at the nanometer scale. In this contribution we report on tip-enhanced Raman spectroscopy (TERS) of an ultra-thin MoS2 flake on a nanostructured Au on silicon surface forming a two-dimensional (2D) crystal/plasmonic heterostructure. Au nanostructures (shaped in triangles) are prepared by nanosphere lithography and then MoS2 is mechanically exfoliated on top of them...
September 19, 2017: Nano Letters
https://www.readbyqxmd.com/read/28925685/broad-range-electrically-tunable-plasmonic-resonances-of-multilayer-coaxial-nanohole-array-with-electroactive-polymer-wrapper
#6
Ziwei Zhou, Ye Yu, Ningwei Sun, Helmuth Möhwald, Panpan Gu, Liyan Wang, Wei Zhang, Tobias A F Koenig, Andreas Fery, Gang Zhang
Plasmonic assemblies featuring high sensitivity that can be readily shifted by external fields are keys for sensitive and versatile sensing devices. In this paper, novel fast-responsive plasmonic nanocomposite composed of multilayer nanohole array and responsive electrochromic polymer is proposed with plasmonic mode appearance vigorously cycled upon orthogonal electrical stimuli. In this nanocomposite, the coaxially stacked plasmonic nanohole arrays can induce multiple intense Fano resonances, which result from the crosstalk between a broad surface plasmon resonance (SPR) and the designed discrete transmission peaks with ultrahigh sensitivity; while the polymer wrapper could provide the sensitive nanohole array with real-time-varied surroundings of refractive indices upon electrical stimuli...
September 19, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28925378/spectroscopically-forbidden-infra-red-emission-in-au-vertical-graphene-hybrid-nanostructures
#7
A K Sivadasan, Santanu Parida, Subrata Ghosh, Ramanathaswamy Pandian, Sandip Dhara
Implementation of Au nanoparticles (NPs) is a subject for frontier plasmonic research due to its fascinating optical properties. Herein, the present study deals with plasmonic assisted emission properties of Au NPs-vertical graphene (VG) hybrid nanostructures. The influence of effective polarizability of Au NPs on the surface enhanced Raman scattering and luminescence properties is investigated. In addition, a remarkable infra-red (IR) emission in the hybrid nanostructures is observed and interpreted on the basis of intra-band transitions in Au NPs...
September 19, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28924963/combining-metabolic-and-process-engineering-strategies-to-improve-recombinant-glycoprotein-production-and-quality
#8
Eric Karengera, Yves Durocher, Gregory De Crescenzo, Olivier Henry
Increasing recombinant protein production while ensuring a high and consistent protein quality remains a challenge in mammalian cell culture process development. In this work, we combined a nutrient substitution approach with a metabolic engineering strategy that improves glucose utilization efficiency. This combination allowed us to tackle both lactate and ammonia accumulation and investigate on potential synergistic effects on protein production and quality. To this end, HEK293 cells overexpressing the pyruvate yeast carboxylase (PYC2) and their parental cells, both stably producing the therapeutic glycoprotein interferon α2b (IFNα2b), were cultured in media deprived of glutamine but containing chosen substitutes...
September 18, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28924717/the-preparation-of-au-tio2-yolk-shell-nanostructure-and-its-applications-for-degradation-and-detection-of-methylene-blue
#9
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/28922603/semiconductor-plasmon-induced-upconversion-enhancement-in-mcu2-xs-sio2-y2o3-yb-3-er-3-core-shell-nanocomposites
#10
Donglei Zhou, Dongyu Li, Xiangyu Zhou, Wen Xu, Xu Chen, Dali Liu, Yongsheng Zhu, Hongwei Song
The ability to modulate the intensity of electromagnetic field by semiconductor plasmon nanoparticles is becoming attractive owing to its unique doping induced local surface plasmon resonance (LSPR) effect different from metals. Herein, we synthesized the mCu2-xS@SiO2@Y2O3:Yb(3+),Er(3+) core-shell composites and experimentally and theoretically studied the semiconductor plasmon induced upconversion (UC) enhancement, and obtained 30 folds UC enhancement compared to that of SiO2@Y2O3:Yb(3+),Er(3+) composites...
September 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28921944/plasmonic-silicon-quantum-dots-enabled-high-sensitivity-ultra-broadband-photodetection-of-graphene-based-hybrid-phototransistors
#11
Zhenyi Ni, Lingling Ma, Sichao Du, Yang Xu, Meng Yuan, Hehai Fang, Zhen Wang, Mingsheng Xu, Dongsheng Li, Jianyi Yang, Weida Hu, Xiaodong Pi, Deren Yang
Highly sensitive photodetection even approaching the single-photon level is critical to many important applications. Graphene-based hybrid phototransistors are particularly promising for high-sensitivity photodetection because they have high photoconductive gain due to the high mobility of graphene. Given their remarkable optoelectronic properties and solution-based processing, colloidal quantum dots (QDs) have been preferentially used to fabricate graphene-based hybrid phototransistors. However, the resulting QD/graphene hybrid phototransistors face the challenge of extending the photodetection into the technologically important mid-infrared (MIR) region...
September 18, 2017: ACS Nano
https://www.readbyqxmd.com/read/28920905/electrochemical-impedance-spectroscopy-on-interdigitated-gold-microelectrodes-for-glycosylated-human-serum-albumin-characterization
#12
Nadra Bohli, Hanen Chammem, Olivier Meilhac, Laurence Mora, Adnane Abdelghani
Glycosylated albumin is considered as a potentially accurate indicator of shorter-term average glucose concentration compared to the current standard HbA1c and as such, it's attracting the interest of the scientific community as a possible diagnosis marker for diabetic patients. The purpose of this paper is to achieve a better understanding of the glycation effect of albumin on its electrochemical properties. That is done through the use of Interdigitated gold microelectrodes (IDGE) as support in a label free impedimetric immunosensor for detection of human serum albumin detection in glycated (GA) and non-glycated (HSA) form...
September 14, 2017: IEEE Transactions on Nanobioscience
https://www.readbyqxmd.com/read/28920844/identification-of-genes-involved-in-galactooligosaccharide-utilization-in-bifidobacterium-breve-strain-yit-4014t
#13
Hidetsugu Sotoya, Akira Shigehisa, Taeko Hara, Hoshitaka Matsumoto, Hiroshi Hatano, Takahiro Matsuki
Galactooligosaccharides (GOS) are mixed oligosaccharides that are mainly composed of galactosyllactoses (GLs), which include 3'-GL, 4'-GL, and 6'-GL. Data from numerous in vitro and in vivo studies have shown that GOS selectively stimulate the growth of bifidobacteria. Previously, we identified the gene locus responsible for 4'-GL utilization, but the selective routes of uptake and catabolism of 3'- and 6'-GL remain to be elucidated. In this study, we used differential transcriptomics to identify the utilization pathways of these GLs within the Bifidobacterium breve YIT 4014T strain...
September 18, 2017: Microbiology
https://www.readbyqxmd.com/read/28920599/magnetic-nanoparticle-enhanced-surface-plasmon-resonance-biosensor-for-extracellular-vesicle-analysis
#14
Agnes T Reiner, Nicolas-Guillermo Ferrer, Priyamvada Venugopalan, Ruenn Chai Lai, Sai Kiang Lim, Jakub Dostálek
The sensitive analysis of small lipid extracellular vesicles (EVs) by using a grating-coupled surface plasmon resonance (GC-SPR) biosensor has been reported. In order to enable the analysis of trace amounts of EVs present in complex liquid samples, the target analyte is pre-concentrated on the sensor surface by using magnetic nanoparticles and its affinity binding is probed by wavelength interrogation of SPR. The GC-SPR has been demonstrated to allow for the implementation of efficient pulling of EVs to the sensor surface by using magnetic nanoparticles and an external magnetic field gradient applied through the sensor chip...
September 18, 2017: Analyst
https://www.readbyqxmd.com/read/28920115/gold-nanodome-sers-platform-for-label-free-detection-of-protease-activity
#15
Pieter C Wuytens, Hans Demol, Nina Turk, Kris Gevaert, Andre G Skirtach, Mohamed Lamkanfi, Roel Baets
Surface-enhanced Raman scattering provides a promising technology for sensitive and selective detection of protease activity by monitoring peptide cleavage. Not only are peptides and plasmonic hotspots similarly sized, Raman fingerprints also hold large potential for spectral multiplexing. Here, we use a gold-nanodome platform for real-time detection of trypsin activity on a CALNNYGGGGVRGNF substrate peptide. First, we investigate the spectral changes upon cleavage through the SERS signal of liquid-chromatography separated products...
September 18, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28918231/highly-sensitive-surface-plasmon-resonance-biosensor-for-the-detection-of-hiv-related-dna-based-on-dynamic-and-structural-dna-nanodevices
#16
Wei Diao, Min Tang, Shijia Ding, Xinmin Li, Wenbin Cheng, Fei Mo, Xiaoyu Yan, Hongmin Ma, Yurong Yan
Early detection, diagnosis and treatment of human immune deficiency virus (HIV) infection is the key to reduce acquired immunodeficiency syndrome (AIDS) mortality. In our research, an innovative surface plasmon resonance (SPR) biosensing strategy has been developed for highly sensitive detection of HIV-related DNA based on entropy-driven strand displacement reactions (ESDRs) and double-layer DNA tetrahedrons (DDTs). ESDRs as enzyme-free and label-free signal amplification circuit can be specifically triggered by target DNA, leading to the cyclic utilization of target DNA and the formation of plentiful double-stranded DNA (dsDNA) products...
September 9, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28918188/the-effect-of-thiolated-phospholipids-on-formation-of-supported-lipid-bilayers-on-gold-substrates-investigated-by-surface-sensitive-methods
#17
Abdulhalim Kılıç, M Fazeli Jadidi, Hakan Özgür Özer, Fatma Neşe Kök
Most of the model lipid membrane studies on gold involve the usage of various surface-modification strategies to rupture liposomes and induce lipid bilayer formation since liposomes with polar surfaces do not interact with bare, hydrophobic gold. In this study, a thiol-modified phospholipid, 1,2-Dipalmitoyl-sn-Glycero-3-Phosphothioethanol (DPPTE) was incorporated into phosphatidylcholine (PC) based liposomes to form supported lipid bilayer (SLB) on gold surfaces without further modification. The binding kinetics of liposomes with different DPPTE ratio (0...
September 8, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28917772/disordered-photonics-coupled-with-embedded-nano-au-plasmonics-inducing-efficient-photocurrent-enhancement
#18
Jing Li, Junling Wang, Zhihui Dai, Hongbo Li
Spatial order used to be considered as a benefit for photonics; but recently the study of disorder has broken into people's horizons for its strong random scattering of light. In this work, disordered photonics coupled with plasmonics for efficiently enhanced photocurrent was first investigated using Au-ZnO nanowire array as a model. The embedded Au-ZnO nanowire array was facilely prepared using a template-free electrodeposition method. On the optimal plasmonic substrate, the photocurrent of disorder-enhanced Au-ZnO nanowire array is about 20-fold that of ZnO nanowire array...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28917747/colorimetric-detection-of-ammonia-using-smartphones-based-on-localized-surface-plasmon-resonance-of-silver-nanoparticles
#19
Amirmostafa Amirjani, Davoud Haghshenas Fatmehsari
In this work, a rapid and straightforward method was developed for colorimetric determination of ammonia using smartphones. The mechanisms is based on the manipulation of the surface plasmon band of silver nanoparticles (AgNPs) via the formation of Ag (NH3)2(+) complex. This complex decreases the amount of AgNPs in the solution and consequently, the color intensity of the colloidal system decreases. Not only the variation in color intensity of the solution can be tracked by a UV-vis spectrophotometer, but also a smartphone can be employed to monitor the color intensity variation by RGB analysis...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28917200/improved-visible-light-activities-for-degrading-pollutants-on-tio2-g-c3n4-nanocomposites-by-decorating-spr-au-nanoparticles-and-2-4-dichlorophenol-decomposition-path
#20
Amir Zada, Yang Qu, Sharafat Ali, Ning Sun, Hongwei Lu, Rui Yan, Xuliang Zhang, Liqiang Jing
It has been clearly demonstrated that the visible-light photocatalytic activities of g-C3N4 (CN) for degrading 2,4-dichlorophenol (2,4-DCP) and bisphenol A (BPA) could be improved by fabricating nanocomposites with a proper amount of nanocrystalline anatase TiO2. Interestingly, the visible-light activities of the amount-optimized nanocomposite could be further improved after decorating Au nanoparticles, with 5.11- and 3.1-time improvement respectively for 2,4-DCP and BPA compared to that of CN, even much higher than that of P25 TiO2 under UV-vis irradiation...
September 7, 2017: Journal of Hazardous Materials
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