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Analytical Chemistry

Martin Köhler, Christoph Neff, Camilo Perez, Cyrill Brunner, Els Pardon, Jan Steyaert, Gisbert Schneider, Kaspar P Locher, Renato Zenobi
The application of nanobodies as binding partners for structure stabilization in protein x-ray crystallography is taking an increasingly important role in structural biology. However, the addition of nanobodies to the crystallization matrices might complicate the optimization of the crystallization process, which is why analytical techniques to screen and characterize suitable nanobodies are useful. Here, we show how chemical cross-linking combined with high-mass matrix-assisted laser/desorption ionization mass spectrometry can be employed as a fast screening technique to determine binding specificities of intact nanobody•membrane protein complexes...
March 21, 2018: Analytical Chemistry
Yanbing Zhai, Siyu Liu, Lijuan Gao, Lili Hu, Wei Xu
With improved performances, miniature mass spectrometers are becoming suitable for more practical applications. At the same time, the coupling of an approximate ionization source is essential in terms of minimizing sample preparation and broadening the range of samples that could be analyzed. In this study, an atmospheric pressure laserspray ionization (AP-LSI) source was coupled with our home developed miniature ion trap mass spectrometer. The whole system is compact in size, and biological samples could be directly analyzed with minimum sample preparation...
March 21, 2018: Analytical Chemistry
Sheila Sharp, Scott J Mitchell, Monique Vallée, Elena Kuzmanova, Michelle Cooper, Delia Belelli, Jeremy J Lambert, Jeffrey T-J Huang
Neurosteroids are brain-derived steroids, capable of rapidly modulating neuronal excitability in a non-genomic manner. Dysregulation of their synthesis, or metabolism has been implicated in many pathological conditions. Here, we describe an isotope dilution based targeted and non-targeted (ID-TNT) profiling of carbonyl neurosteroids/steroids. The method combines stable isotope dilution, hydroxylamine derivatization, high-resolution MS scanning and data dependent MS/MS analysis, allowing absolute quantification of pregnenolone, progesterone, 5α-dihydroprogesterone, 3α,5α-tetrahydroprogesterone and 3β,5α-tetrahydroprogesterone, and relative quantification of other carbonyl containing steroids...
March 21, 2018: Analytical Chemistry
Huifeng Yu, Yanming An, Marcos Daniel Battistel, John F Cipollo, Darón I Freedberg
Conjugate vaccines are highly heterogeneous in terms of glycosylation sites and linked oligosaccharide length. Therefore, the characterization of conjugate vaccines' glycosylation state is challenging. However, improved product characterization can lead to enhancements in product control and product quality. Here, we present a synergistic combination of high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy for the analysis of glycoconjugates. We use the power of this strategy to characterize model polysaccharide conjugates to demonstrate a detailed level of glycoproteomic analysis...
March 21, 2018: Analytical Chemistry
Cezar A Bizzi, Sandra M Cruz, Lucas Schmidt, Robert A Burrow, Juliano S Barin, Jose N G Paniz, Erico M M Flores
A new method for analytical applications based on the Maxwell-Wagner effect is proposed. Considering the interaction of carbonaceous materials with an electromagnetic field in the microwave frequency range, a very fast heating is observed due to interfacial polarization that results in localized microplasma formation. Such effect was evaluated in this work using a monomode microwave system, and temperature was recorded using an infrared camera. For analytical applications, a closed reactor under oxygen pressure was evaluated...
March 21, 2018: Analytical Chemistry
Yunfang Jia, Fang Li
Functional nucleic acids (FNAs) are promising sensing elements, extensive interests are excited to integrate FNAs with transducers for biochemical assays. However, efforts for FNAs modified light-addressable-potentiometric-sensor (FNA-LAPS) are rarely reported. LAPS is a versatile transducer with electrolyte-insulator-semiconductor (EIS) structure, can respond almost any surface electronic deviations. Herein, organized studies for FNA-LAPS including experiments, theoretical derivations and MEDICI (Synopsys®) simulations, are presented using Pb2+ -DNAzyme GR-5 and Ag+ -aptamer as proof-of-concepts, which are typical FNAs with distinctive sensing strategies...
March 21, 2018: Analytical Chemistry
Huifang Liu, Fei Zhao, Choong Eun Jin, Bonhan Koo, Eun Yeong Lee, Linlin Zhong, KyuSik Yun, Yong Shin
Nucleic acid-based diagnostics are widely used for clinical applications due to their powerful recognition of biomolecule properties. Isolation and purification of nucleic acids such as DNA and RNA in the diagnostic system have been severely hampered in point-of-care testing because of low recovery yields, degradation of nucleic acids due to the use of chaotropic detergent and high temperature, and the requirement of large instruments such as centrifuges and thermal controllers. Here, we report a novel large instrument- and detergent-free assay via binary nanomaterial for ultrasensitive nucleic acid isolation and detection from cells (eukaryotic and prokaryotic)...
March 21, 2018: Analytical Chemistry
Mika Ishigaki, Paralee Puangchit, Yui Yasui, Akane Ishida, Hiroki Hayashi, Yoshihiko Nakayama, Hideya Taniguchi, Ichiro Ishimaru, Yukihiro Ozaki
In the present study, we successfully obtained non-staining blood flow images of a developing fish egg embryo using optical interference caused by the Doppler shift. The spectral distribution of light reflected by moving objects such as the heart and red cells was found to be different from that of the incident light because of the Doppler effect. Interference between different frequency components was observed in an interferogram through heterodyne interaction using an imaging-type two-dimensional Fourier spectroscopic system, and information on the intensities of the spectral components was obtained by Fourier transformation...
March 21, 2018: Analytical Chemistry
Mindy Elizabeth Hair, Adrianna I Mathis, Erica K Brunelle, Lenka Halámková, Jan Halámek
Sweat is a biological fluid present on the skin surface of every individual and is known to contain amino acids as well as other low molecular weight compounds. Each individual is inherently different from one another based on certain factors including, but not limited to, his/her genetic make-up, environment, and lifestyle. As such, the biochemical composition of each person greatly differs. The concentrations of the biochemical content within an individual's sweat are largely controlled by metabolic processes within the body that fluctuate regularly based on attributes such as age, gender, and activity levels...
March 21, 2018: Analytical Chemistry
Yury I Kostyukevich, Alexey S Kononikhin, Igor A Popov, Eugene N Nikolaev
We present the accurate analytical solution obtained for the system of rate equations describing the isotope exchange process for molecule containing arbitrary number of equivalent labile atoms. The exact solution was obtained using Mathematica 7.0 software and this solution has the form of the time-dependent Gaussian distribution. For the case when forward exchange considerable overlaps the back exchange it is possible to estimate the activation energy of the reaction by obtaining a temperature dependence of the reaction degree...
March 20, 2018: Analytical Chemistry
Li Cui, Kai Yang, Hong-Zhe Li, Han Zhang, Jian-Qiang Su, Maria Paraskevaidi, Francis Luke Martin, Bin Ren, Yong-Guan Zhu
Nitrogen (N) fixation is the conversion of inert nitrogen gas (N2) to bioavailable N essential for all forms of life. N2-fixing microorganisms (diazotrophs), which play a key role in global N cycling, remain largely obscure because a large majority are uncultured. Direct probing of active diazotrophs in the environment is still a major challenge. Herein, a novel culture-independent single-cell approach combining resonance Raman (RR) spectroscopy with 15N2 stable isotope probing (SIP) was developed to discern N2-fixing bacteria in a complex soil community...
March 20, 2018: Analytical Chemistry
Shan-Shan Li, Wen-Yi Zhou, Min Jiang, Zheng Guo, Jinhuai Liu, Lizhi Zhang, Xing-Jiu Huang
Developing a new ultra-sensitive interface to detect As(III) is highly desirable because of its seriously toxic and low concentration in drinking water. Recently, Fe3O4 nanoparticles of high adsorption toward As(III) become very promising to be such an interface, which is still limited by the poor understanding of their surface physicochemical properties. Herein, we report that dumbbell-like Au/Fe3O4 nanoparticles, when being modified the screen-printed carbon electrode, can serve as an efficient sensing interface for As(III) detection with an excellent sensitivity of 9...
March 20, 2018: Analytical Chemistry
Xue Li, Lanlan Pan, Lin Wei, Zunyan Yi, Xiao Wang, Zhongju Ye, Lehui Xiao, Hung-Wing Li, Jianfang Wang
Prostate-specific antigen (PSA) is an intercellular glycoprotein produced primarily by the prostate gland, which is commonly chosen as the initial target for the early diagnosis of prostate cancer. In this work, we demonstrate a simple yet sensitive sandwich-type single-particle enumeration (SPE) immunoassay for the quantitative detection of PSA in a flow chamber. The design is based on the luminescence resonance energy transfer (LRET) between upconversion nanoparticles (UCNPs) and gold nanoparticles (GNPs)...
March 20, 2018: Analytical Chemistry
Muge Yucel, Osman Akin, Mehmet Cayoren, Ibrahim Akduman, Alagappan Palaniappan, Bo Liedberg, Gurkan Hizal, Fatih Inci, Umit Hakan Yildiz
This study reports on a handheld volatilome analyzer for selective determination of clinically relevant biomarkers in exhaled breath. The sensing platform is based on electrospun polymer nanofiber-multi walled carbon nanotube (MWCNT) sensing micro-channels. Polymer nanofibers of poly(vinylidene fluoride) (PVDF), polystyrene (PS), and poly(methyl methacrylate) (PMMA) incorporated with MWCNT exhibits stable response to interferences of humidity and CO2 and provides selective deformations upon exposure of exhaled breath target volatilomes acetone and toluene, exhibiting correlation to diabetes and lung cancer, respectively...
March 20, 2018: Analytical Chemistry
Nathaniel E Kallmyer, Joseph Musielwicz, Joel Sutter, Nigel Forest Reuel
Hydrolytic enzymes are a topic of continual study and improvement due to their industrial impact and biological implications; however, the ability to measure the activity of these enzymes, especially in high-throughput assays, is limited to an established, few enzymes and often involves the measurement of secondary byproducts or the design of a complex degradation probe. Herein, a versatile single-walled carbon nanotube (SWNT)-based biosensor that is straightforward to produce and measure is described. The hydrolytic enzyme substrate is rendered as an amphiphilic polymer which is then used to solubilize the hydrophobic nanotubes...
March 20, 2018: Analytical Chemistry
Supone Manakasettharn, Akira Takahashi, Tohru Kawamoto, Keiko Noda, Yutaka Sugiyama, Tohru Nakamura
Ammonia gas is useful but caustic thus its concentration is monitored depending on applications. We prepared indium hexacyanoferrate nanoparticles (InHCF-NPs, HCF = [FeII (CN)6 ]4- ) with average diameter around 8 nm by simple reaction at room temperature between In cations and HCF anions, and found the unique functionality of InHCF-NPs which were capable of highly sensitive (16 ppb) and exceptionally wide range (190000, 16 ppb - 0.3 %) detection of ammonia gas within 6 min by IR measurements. Slope changes of the IR peak ratio of adsorbed ammonium over CN moieties in InHCF framework indicated a good log-log linear correlation along gas concentrations, in which wide dynamic range over 105 was realized for the first time in the field of ammonia gas detection...
March 20, 2018: Analytical Chemistry
Tao Jia, Di Gao
Molecular dynamics simulation is employed to investigate the microscopic heat current inside an argon-copper nanofluid. Wavelet analysis of the microscopic heat current inside the nanofluid system is conducted. The signal of the microscopic heat current is decomposed into two parts: one is the approximation part; the other is the detail part. The approximation part is associated with the low frequency part of the signal, and the detail part is associated with the high frequency part of the signal. Both the probability distributions of the high frequency and the low frequency parts of the signals demonstrate Gaussian-like characteristics...
March 19, 2018: Analytical Chemistry
Peter Howe
Proton NMR spectra are usually acquired using deuterated solvents but in many cases it is necessary to obtain spectra on samples in protonated solvents. In these cases, the intense resonances of the protonated solvents need to be suppressed to maximise sensitivity and spectral quality. A wide range of highly effective solvent suppression methods have been developed, but additional measures are needed to suppress the13 C satellites of the solvent. Because the satellites represent 1.1% of the original solvent signal, they remain problematic if unsuppressed...
March 19, 2018: Analytical Chemistry
Chiew San Fang, Kwang-Sun Kim, Dat Thinh Ha, Moon-Soo Kim, Haesik Yang
Recombinase polymerase amplification (RPA) has been combined with electrochemical detection for simple and rapid point-of-care testing. However, there are two major hindrances to this simple and rapid testing: (i) washing or purification steps are required to remove unbound labeled probes and interfering species in the sample; (ii) it is difficult to quantify double-stranded DNA (dsDNA) electrochemically by using biospecific affinity binding without dsDNA denaturation. In the present study, we describe a wash-free and rapid electrochemical method to detect RPA-amplified dsDNAs using a zinc finger protein, Zif268...
March 19, 2018: Analytical Chemistry
Chang Feng, Zihan Wang, Tianshu Chen, Xiaoxia Chen, Dongsheng Mao, Jing Zhao, Genxi Li
No abstract text is available yet for this article.
March 19, 2018: Analytical Chemistry
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