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Laura E Masson, Christine M O'Brien, Isaac J Pence, Jennifer L Herington, Jeff Reese, Ton G van Leeuwen, Anita Mahadevan-Jansen
A fiber optic probe-based Raman spectroscopy system using a single laser module with two excitation wavelengths, at 680 and 785 nm, has been developed for measuring the fingerprint and high wavenumber regions using a single detector. This system is simpler and less expensive than previously reported configurations of combined fingerprint and high wavenumber Raman systems, and its probe-based implementation facilitates numerous in vivo applications. The high wavenumber region of the Raman spectrum ranges from 2800-3800 cm-1 and contains valuable information corresponding to the molecular vibrations of proteins, lipids, and water, which is complimentary to the biochemical signatures found in the fingerprint region (800-1800 cm-1), which probes DNA, lipids, and proteins...
November 13, 2018: Analyst
Gergo Peter Szekeres, Janina Kneipp
The interaction of bovine serum albumin (BSA) and human serum albumin (HSA), sharing a sequence similarity of 77.5%, with gold nanoparticles of a size of ∼30 nm was investigated by surface-enhanced Raman scattering (SERS). The spectra provide information on those residues of the proteins in proximity of the nanoparticles. The SERS signals indicate an electrostatic interaction of both proteins with the citrate ligands at the nanoparticle surface via lysine residues. HSA, different from BSA also binds directly to the gold surface by particularly flexible protein segments that were identified by comparison of the vibrational bands with the known amino acid sequence of the molecule...
November 13, 2018: Analyst
Li Fan, Wenjia Zhang, Xiaodong Wang, Wenjuan Dong, Yaoli Tong, Chuan Dong, Shaomin Shuang
We report herein a two-photon ratiometric fluorescent probe (DNEPI) for mitochondrial cysteine (Cys) detection on the basis of a merocyanine (compound 1) as the two-photon fluorophore and a 2,4-dinitrobenzensulfonyl (DNBS) unit as the biothiol reaction site. Upon reaction with Cys in DMSO/PBS (1/1, v/v), DNEPI showed a distinct ratiometric fluorescence emission characteristic (F583 nm/F485 nm) linearly proportional to Cys concentrations over the range of 2-10 μM, which was attribute to the enhanced intramolecular charge transfer (ICT) effect by cleavage of the sulfonic acid ester bond of DNEPI to release compound 1...
November 13, 2018: Analyst
Guilin Chen, Hui Feng, Wenbin Xi, Jing Xu, Saifei Pan, Zhaosheng Qian
Butyrylcholinesterase (BChE) generally acts as an important plasma biomarker for clinical diagnosis due to its major contribution to human plasma cholinesterase levels, but its current fluorometric assay relying on fluorogenic substrates frequently suffers from the lack of sufficiently fast response time and specific recognition of substrates relative to the traditional Ellman's method. In this work, we report a fluorescent molecular probe for assaying BChE activity based on thiol-triggered fluorescence enhancement via thiol-ene click reactions...
November 12, 2018: Analyst
Görkem Bakir, Benoit E Girouard, Robert W Johns, Catherine R-J Findlay, Hans A Bechtel, Max Eisele, Susan G W Kaminskyj, Tanya E S Dahms, Kathleen M Gough
With lethal opportunistic fungal infections on the rise, it is imperative to explore new methods to examine virulence mechanisms. The fungal cell wall is crucial for both the virulence and viability of Aspergillus nidulans. One wall component, Galf, has been shown to contribute to important fungal processes, integrity of the cell wall and pathogenesis. Here, we explore gene deletion strains lacking the penultimate enzyme in Galf biosynthesis (ugmAΔ) and the protein that transports Galf for incorporation into the cell wall (ugtAΔ)...
November 9, 2018: Analyst
Michaela Schwaiger, Harald Schoeny, Yasin El Abiead, Gerrit Hermann, Evelyn Rampler, Gunda Koellensperger
A novel integrated metabolomics/lipidomics workflow is introduced enabling high coverage of polar metabolites and non-polar lipids within one analytical run. Dual HILIC and RP chromatography were combined to high-resolution mass spectrometry. As a major advantage, only one data file per sample was obtained by fully automated simultaneous analysis of two extracts per sample. Hence, the unprecedented high coverage without compromise on analytical throughput was not only obtained by the orthogonality of the chromatographic separations, but also by the implementation of dedicated sample preparation procedures resulting in optimum extraction efficiency for both sub-omes...
November 9, 2018: Analyst
Datong Wu, Wensheng Tan, Hongda Li, Zhangchen Lei, Linhong Deng, Yong Kong
Conductive materials are valuable supports and widely applied in electrochemical analysis. In the current article, a mesoporous organosilica sphere (S,S)-CPMO-3 with the chiral group and electroactive units is presented. The organosilicon framework is composed of free ions belonging to the ionic liquid and the chiral group arising from (1S,2S)-1,2-diaminocyclohexane. Next, a bare electrode was modified by the as-synthesized composite material to construct the new electrochemical sensor (S,S)-CPMO-3-GCE. It was observed that (S,S)-CPMO-3-GCE exhibited favourable enantioselective recognition in the response of the peak current (Ip) and the peak potential (Ep) to the different configurations of amino acids...
November 9, 2018: Analyst
Antonio Marín-Romero, Agustín Robles-Remacho, Mavys Tabraue-Chávez, Bárbara López-Longarela, Rosario M Sánchez-Martín, Juan J Guardia-Monteagudo, Mario A Fara, Francisco J López-Delgado, Salvatore Pernagallo, Juan J Díaz-Mochón
A novel sensitive, specific and rapid method for the detection and quantification of microRNAs without requiring extraction from their biological sources is now available using a novel chemical based, PCR-free technology for nucleic acid testing. In this study, we both demonstrate how this method can be used to profile miR-451a, an important miRNA in erythropoiesis, and compare with the gold standard RT-qPCR.
November 9, 2018: Analyst
Zhongdi Tang, Kai Jiang, Shan Sun, Sihua Qian, Yuhui Wang, Hengwei Lin
In this work, a bioprobe for the detection of dopamine was designed and fabricated through covalently linking fluorescent carbon dots (CDs) and tyrosinase (TYR). The bioprobe (named CDs-TYR) can catalyze oxidation of dopamine and produce dopaquinone, and consequently the fluorescence of the CDs was quenched due to an efficient electron transfer mechanism from excited CDs to dopaquinone. The fluorescence intensity of CDs decreased in a dopamine-concentration-dependent manner, which built the foundation of dopamine quantification...
November 9, 2018: Analyst
Zhong-Xia Wang, Yuan-Fei Gao, Xian-He Yu, Fen-Ying Kong, Wen-Juan Wang, Wei-Xin Lv, Wei Wang
Herein, we employ pH-dependent solubility equilibrium to develop the one-pot aqueous synthesis of dual-color emission fluorescent carbon nanosphere (DFCSs) with novel physicochemical properties. Unexpectedly, some of the DFCSs have a regular nanosphere shape, containing uniform carbon dots (∼20 nm) on their surface. This may be attributed to the change in the surface composition of the carbon nanospheres under the strong alkaline conditions (pH 13), which results in dual-wavelength emission by single-wavelength excitation...
November 9, 2018: Analyst
Sayed Tayyab Raza Naqvi, Bahareh Shirinfar, Saadat Majeed, Muhammad Najam-Ul-Haq, Dilshad Hussain, Tanyia Iqbal, Nisar Ahmed
Cerium-based materials possess redox properties due to the presence of dual valence states of Ce3+ and Ce4+. In the last few years, the scientific community has paid much attention to designing and synthesizing cerium-based materials through advantageous routes for widespread catalytic and sensing applications in many fields. Cerium materials have been synthesized in many different forms, shapes and sizes. The catalytic and sensing capabilities of cerium nanostructures are highly dependent on their morphologies and can be improved significantly by modifying the sizes and shapes of the nanostructures to develop sensing scaffolds with improved sensing performance...
November 9, 2018: Analyst
Yun Chai, Yuting Gao, Huiwen Xiong, Wanqian Lv, Guichun Yang, Cuifen Lu, Junqi Nie, Chao Ma, Zuxing Chen, Jun Ren, Feiyi Wang
Leucine aminopeptidase (LAP), one of the important cancer-related biomarkers, is significantly over-expressed in many malignant tumor cells. Developing an effective fluorescent probe for high-specificity and in situ trapping of endogenous LAP in living samples is still challenging. In this project, we report a water-soluble near-infrared (NIR) fluorescent probe (CHMC-M-Leu) for specific monitoring of LAP in vitro and in vivo. The novel fluorescent probe (CHMC-M-Leu) contains a NIR-emitting fluorophore (CHMC-M) as the reporter and l-leucine as the enzyme-active trigger moiety which are linked together by a p-aminobenzyl alcohol (PABA) section...
November 8, 2018: Analyst
Xinying Mu, Stan Remiszewski, Mark Kon, Ayşegül Ergin, Max Diem
This paper reviews methods to arrive at optimum decision tree or label tree structures to analyze large SHP datasets. Supervised methods of analysis can utilize either sequential or (flat) multi-classifiers depending on the variance in the data, and on the number of spectral classes to be distinguished. For small number of spectral classes, multi-classifiers have been used in the past, but for the analysis of datasets containing large numbers (∼20) of disease or tissue types, mixed decision tree structures were found to be advantageous...
November 8, 2018: Analyst
Dongmei Wang, Hongmei Hua, Haoran Tang, Cheng Yang, Wei Chen, Yongxin Li
In this work, a label-free electrochemical apta-nanosensor was fabricated on a single gold nanodisk electrode (AuNDE) for thrombin sensing with high sensitivity via a novel signal amplification strategy. This recognition platform was fabricated via self-assembly of helper DNA (HP-DNA), thrombin-binding aptamer (TBA) and gold nanoparticle (AuNP)-DNA complexes to form a sandwich structure on the AuNDE surface. A novel signal amplification strategy via designed AuNP-DNA complexes was introduced using Ru(NH3)63+ as the signal reporter based on the electrostatic interaction...
November 8, 2018: Analyst
Bhupendra Kumar Dwivedi, Roop Shikha Singh, Afsar Ali, Vinay Sharma, Shaikh M Mobin, Daya Shankar Pandey
Piperazine appended naphthalimide-BODIPYs (NPB1-NPB4) exhibiting solvatochromism and aggregation-induced emission with a large Stokes shift (up to 146 nm) have been described. Separation of naphthalimide and BODIPY fluorophores by piperazine in these conjugates creates a donor-acceptor system and induces twisted intramolecular charge transfer, in addition to photoinduced electron transfer. The crucial role of naphthalimide, the alkyl chain length, the piperazine ring, and the solid-state packing on AIE has been extensively investigated by various studies...
November 8, 2018: Analyst
Yongming Guo, Wei Zhao
The rapid and sensitive detection of water or humidity has attracted wide interest because of their considerable significance in the chemical industry and other fields. Nanotechnology offers potential tools in the construction of various luminescent nanosensors for sensing water or relative humidity (RH). In this review, we present the recent advances in different luminescent nanomaterials, namely, luminescent copper nanoclusters, carbon quantum dots, metal-organic frameworks, covalent organic frameworks and other nanomaterials, in the detection of water and RH...
November 8, 2018: Analyst
Bo Peng, Zaiyong Zhang, Jian-Rong Wang, Meiqi Li, Qi Zhang, Xuefeng Mei
Discrimination of active pharmaceutical ingredients (APIs) existing as neutral molecules or salts is essential and complicated. However, the discrimination of pharmaceutical salts by confocal Raman micro-spectroscopy remains relatively poorly understood. In this paper, four new salts of triamterene (Tri) cocrystallized with nicotinic acid (NA), benzoic acid (BA), p-toluenesulfonic acid (TA), or isonicotinic acid (INA) were prepared and characterized comprehensively by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), polarized light microscopy (PLM), and dynamic vapor sorption (DVS)...
November 8, 2018: Analyst
Hengchang Ma, Manyi Yang, Shaoxiong Zhang, Pei Yin, Tao Wang, Yuan Yang, Ziqiang Lei, Yucheng Ma, Yanfang Qin, Zengming Yang
Fluorescent probes are powerful tools for investigating reactive oxygen species (ROS) in living organisms. The overproduced "primary" ROS of superoxide anions (O2˙-) cause a chain of oxidative damage. In order to monitor O2˙- level fluctuations in living cells, we synthesized two reaction-type probes of TPA-DHP-1,2,3 and TPA-PPA-1,2,3, which were composed of an electron-rich triphenylamine (TPA) and the very active functional groups of dihydropyridine (DHP) and pyridinium (PPA). Intriguingly, DHP and PPA were able to carry out easy proton abstractions and nucleophilic reactions in the presence of O2˙-, resulting in the corresponding products with sharp wavelength shifts, and elevated fluorescence intensities...
November 8, 2018: Analyst
James Doherty, Alan Raoof, Ansaf Hussain, Magda Wolna, Gianfelice Cinque, Michael Brown, Peter Gardner, Joanna Denbigh
Synchrotron radiation Fourier transform infrared microspectroscopy (SR-microFTIR) of live biological cells has the potential to provide far greater biochemical and morphological detail than equivalent studies using dehydrated, chemically-fixed single cells. Attempts to measure live cells using microFTIR are complicated by the aqueous environment required and corresponding strong infrared absorbance by water. There is also the additional problem of the limited lifetime of the cells outside of their preferred culture environment...
November 7, 2018: Analyst
Luis Felipe das Chagas E Silva de Carvalho, Marcelo Saito Nogueira
Oral injuries are currently diagnosed by histopathological analysis of biopsy, which is an invasive procedure and does not give immediate results. On the other hand, the Raman spectroscopy technique is a real-time and minimally invasive analytical tool with a notable diagnostic capability. At the current stage, researchers are widely aware of the diagnostic potential of the technique and how it is considered promising for providing biochemical information in real time and without damaging the tissue. The problem originates from a lack of relevant studies and clinical trials that could show the actual use of Raman spectroscopy to help patients...
November 7, 2018: Analyst
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