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Analytica Chimica Acta

Qingwei Huang, Chuan He, Jinli Zhang, Wei Li, Yan Fu
Carboxylic acids have been efficiently used to activate H2 O2 to form even more potent oxidant-peroxy acids through enzyme-catalyzed processes. By employing acetic acid as the activator, herein we report for the first time that cofactor-free DNA displays unexpected activity in H2 O2 -mediated oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) under mild conditions. A series of 10-nt oligonucleotides were rationally designed with various combinations of double nucleotides including TG, AG, CG, TA and AC respectively, which demonstrates that the catalytic performance of DNA is highly dependent upon the sequence composition, strand length and continuous nucleotides...
May 9, 2019: Analytica Chimica Acta
Yucai Yang, Yue Huang, Chao Li
Here we report an electrochemical DNA (E-DNA) sensor to detect a variety of analytes by using a novel interfacial probe that rationally integrates triplex-forming oligonucleotide (TFO) into a tetrahedral DNA nanostructure (TDN). In the presence of analyte, the blocked TFO is released and subsequently binds the edge of TDN to form a triplex DNA structure, which confines the redox reporter to be in close proximity to the underlying electrode and enhances the electrochemical signal. Thanks to the unique design and property of the probe, the proposed sensor could efficiently suppress the background signal (from 0...
May 9, 2019: Analytica Chimica Acta
Shi Gang Liu, Shi Mo, Lei Han, Na Li, Yu Zhu Fan, Nian Bing Li, Hong Qun Luo
Ratiometric sensing suffers from less interference and can obtain more accurate results than single-signal assay. Here, a new ratiometric optical sensing strategy for H2 O2 detection is developed by etching silver nanoparticles (AgNPs) to deactivate fluorescence resonance energy transfer (FRET) and reduce Rayleigh scattering based on a hyphenated technique of fluorescence and second-order Rayleigh scattering (SRS). The ratiometric detection of H2 O2 is achieved through exploiting a hybrid system fabricated by fluorescent carbon dots and silver nanoparticles (CDs/AgNPs)...
May 9, 2019: Analytica Chimica Acta
Grenalynn C Ilacas, Alexis Basa, Katherine J Nelms, Joshua D Sosa, Yangyang Liu, Frank A Gomez
This paper describes the development of two microfluidic paper-based analytical devices (μPADs), one well-based and the other based on a lateral flow assay (LFA) configuration, to detect glucose via a colorimetric assay using the solid metal-organic framework (MOF) Zr-PCN-222(Fe), to encapsulate glucose oxidase (GOx). The well-based platform consisted of laminate sheets and multiple layers of wax-printed chromatography paper. Solutions of KI and glucose placed into the well flowed through the device and reacted with the GOx@MOF species sandwiched between the paper layers realizing a yellow-brown color...
May 9, 2019: Analytica Chimica Acta
Mojtaba Shamsipur, Leila Samandari, Avat Arman Taherpour, Afshin Pashabadi
This study introduces a signal amplification strategy rely on incorporating a specific polymer film between two typical nanostructured layers, aiming to improve the electrical properties of the platform to be able to transduce small binding event through sub-femtomolar detection of HIV-1 gene at the surface of the constructed biosensing device. The proposed composite was arrayed based on a conductive layer consist of p-aminobenzoic acid (PABA) sandwiched between the electrochemically reduced graphene oxide (ERGO) as the sub-layer, and the gold nanoparticles (AuNPs) as the interfacial layer...
May 9, 2019: Analytica Chimica Acta
Yongfeng Ning, Xu Cui, Chao Yang, Fengxiang Jing, Xiaojun Bian, Lin Yi, Gang Li
We present a self-discretization and zero-water-loss microfluidic digital PCR (dPCR) device to enable low-cost and robust quantitative nucleic acid assays. In this device, a thin void is integrated beneath the reaction chamber array. By utilizing the permeability of polydimethylsiloxane (PDMS) film, the integrated void serves a dual function: vacuum "accumulator" and hydration "reservoir". The combination of pre-stored pumping energy and water compensation for evaporation loss enables simple, robust and reliable single-DNA-molecule amplification and detection in 10,000 reactors of picoliter volume...
May 9, 2019: Analytica Chimica Acta
Jennifer-Christin Müller, Tanja Berg, Claudia Enders, Peter Leonhard, Uwe Karst
In recent years, liquid crystal displays (LCDs) became more and more popular in industrial and consumer electronics applications. Unevenly distributed liquid crystals (LC) and the presence of organic contaminations in the LC layer, for example from the display sealant, can cause display defects and therefore lower the display quality. This work describes the development of a fast and easy screening method for display samples by laser ablation coupled to atmospheric pressure chemical ionization-mass spectrometry (LA-APCI-MS)...
May 9, 2019: Analytica Chimica Acta
Yanxin Yu, Jinmao You, Zhiwei Sun, Guoliang Li, Zhongyin Ji, Shijuan Zhang, Xuxia Zhou
Chemical isotope labelling in combination with high-performance liquid chromatography-tandem mass spectrometry (CIL-HPLC-MS/MS) is a powerful method for quantitative profiling of targeted molecules. In the current work, we successfully developed a novel CIL-HPLC-MS/MS method for quantitative profiling of residual organophosphorus thioester pesticides (OPTPs) in agricultural products through the determination of the cleavage products of thiol (CP-thiol) compounds. In this method, we synthesized a novel pair of CIL reagents, i...
May 9, 2019: Analytica Chimica Acta
Cheng-Kuan Su, Chia-Che Ho
In this study, a novel analytical method was developed for online profiling of living rat brain extracellular pH. It involved microdialysis (MD) sampling, introduction of metal ions (e.g., Mn, Co, Ni, Cd) as acid/base indicators, and a pH-dependent solid phase extraction (SPE) based on polymer-metal ion interactions as a sample pretreatment scheme prior to analysis through inductively coupled plasma mass spectrometry (ICP-MS). With a 10-μL microdialysate, optimization of the system provided a working pH range from 5...
May 9, 2019: Analytica Chimica Acta
Amrita Soni, Chandra Mouli Pandey, Manoj Kumar Pandey, Gajjala Sumana
In this work, polyaniline nanospindles have been synthesized using iron oxide as sacrificial template. These nanospindles were utilized for the fabrication of PANI-MoS2 nanoflower architectures via hydrothermal route. The electrostatic interaction between PANI and MoS2 improves the conductivity and provides more direct paths for charge transportation. SEM, TEM, XRD, Raman Spectroscopy techniques were employed to explore the crystal structure, and morphological properties of the PANI-MoS2 nanocomposite. Furthermore, an electrochemical biosensing platform based on PANI-MoS2 nanocomposite was fabricated for the specific detection of chronic myelogenous leukemia (CML) by using electrochemical impedance spectroscopy technique...
May 9, 2019: Analytica Chimica Acta
Lian Ma, Qiaran Zhang, Chao Wu, Yue Zhang, Lintao Zeng
Composite nanomaterials are particularly useful and offer many excellent opportunities for electrochemical sensing application. Depending on the high catalytic activity of bimetallic nanoparticles, the large specific surface area, abundant active edges and co-catalytic function of MoS2 nanosheets, we, for the first time, prepared a novel PtNi bimetallic nanoparticles loaded MoS2 nanosheets (PtNi@MoS2 ) hybrid material by a co-reduction method for the electrochemical sensing application. The nanocomposite is characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS), and then casted on a bare glassy carbon electrode (GCE) to fabricate an electrochemical sensor (PtNi@MoS2 /GCE)...
May 9, 2019: Analytica Chimica Acta
Zhen Rong, Qiong Wang, Nanxi Sun, Xiaofei Jia, Keli Wang, Rui Xiao, Shengqi Wang
Simple, inexpensive, and rapid diagnostic tests in low-resource settings with limited laboratory equipment and technical expertise are instrumental in reducing morbidity and mortality from epidemic infectious diseases. We developed a smartphone-based fluorescent lateral flow immunoassay (LFIA) platform for the highly sensitive point-of-care detection of Zika virus nonstructural protein 1 (ZIKV NS1). An attachment was designed and 3D-printed to integrate the smartphone with external optical and electrical components, enabling the miniaturization of the instrument and reduction in cost and complexity...
May 9, 2019: Analytica Chimica Acta
Dongsheng Zhang, Aikun Liu, Ruixue Ji, Jian Dong, Yanqing Ge
A mitochondria-targeted ratiometric fluorescent probe based on the fluorophore pyrido[1,2-a]benzimidazole was developed. It showed high sensitivity and selectivity toward SO2 derivatives in water. The probe was also successfully applied to detect intrinsically generated SO2 derivatives in living glioma cells, which may be helpful in ascertaining the biological roles of SO2 in mitochondria.
May 9, 2019: Analytica Chimica Acta
Kari Kopra, Natalia Tong-Ochoa, Mari Laine, Ville Eskonen, Päivi J Koskinen, Harri Härmä
We have developed a rapid and sensitive universal peptide-based time-resolved luminescence assay for detection of enzymatic post-translational modifications (PTMs). PTMs play essential roles in intracellular signaling and cell regulation, thus providing functional protein diversity in cell. Due this, impaired PTM patterns have been linked to multiple disease states. Clear link between PTMs and pathological conditions have also driven assay development further, but still today most of the methodologies are based on single-specificity or group-specific PTM-recognition...
May 9, 2019: Analytica Chimica Acta
Mengdi Yao, Xuefei Lv, Yulin Deng, Madiha Rasheed
Owing to the pivotal function in post transcriptional gene modification, miRNA biomarkers are playing crucial role in tracking and diagnosing various forms of tumors in a short time period. Hence, the need to develop simple, sensitive and specific detection of miRNAs for precise diagnosis arises. This current study is aimed to develop a detecting platform by combining rolling circle amplification with AuNps-based lateral flow strip (LFS-RCA) for simultaneous detection of miRNA 21 and miRNA let-7a. The current methodology is simple, sensitive, specific and selective for miRNA let-7a and miRNA 21 with the limits of detection (LOD) as low as 20 pM and 40 pM, respectively...
May 9, 2019: Analytica Chimica Acta
Ga-Yeon Lee, Ji-Hong Bong, Ji Yun Kim, Gu Yoo, Min Park, Min-Jung Kang, Joachim Jose, Jae-Chul Pyun
The autoimmune diseases systemic lupus erythematosus (SLE) and Sjogren's syndrome (SS) are diagnosed by detection of autoantibodies against Ro and La protein autoantigens, respectively. In this work, the diagnosis of autoimmune diseases SLE and SS was demonstrated using thermophoresis of Escherichia coli with the autodisplayed autoantigens. Ro and La protein autoantigens were autodisplayed by constitutive expression together with a fluorescent protein called tdTomato in the cytosol. The binding affinity of the autodisplayed autoantigens was tested against positive and control sera by using FACS as a reference method...
May 9, 2019: Analytica Chimica Acta
Yu-Hong Cheng, Yam-Fung Cheung, Toby Siu-Chung Tam, Chun-Nam Lok, Hongzhe Sun, Kwan-Ming Ng
The development of sensitive and specific analytical methods is critical for the discovery of molecular biomarkers, which assists disease diagnosis and understanding biological processes. Herein, a highly sensitive method is developed using antibody-conjugated plasmonic metal nanoparticles for the detection of targeted biomarkers down to low attomole level via coupling of immunoassay techniques with laser ionization mass spectrometry (LI-MS). The conjugated antibodies target specific antigens, while the metal nanoparticles act as mass tags and ion reservoirs for the signal amplification...
May 9, 2019: Analytica Chimica Acta
S E Janssen, R F Lepak, M T Tate, J M Ogorek, J F DeWild, C L Babiarz, J P Hurley, D P Krabbenhoft
The precise quantification of mercury (Hg) stable isotope compositions in low concentration or dilute samples poses analytical challenges due to Hg mass limitations. Common Hg pre-concentration procedures require extended processing times, making rapid Hg stable isotope measurements challenging. Here we present a modified pre-concentration method that combines commonly used Hg reduction and gold trap amalgamation followed by semi-rapid thermal desorption (less than 1 h) and chemical trapping. This custom designed system was demonstrated to perform adequately on multiple trapping matrices including a new bromine monochloride (BrCl) wet oxidant trap (40% 3HNO3 :BrCl), capable of trapping consistently in 2 mL volume over a wide range of Hg masses (5-200 ng)...
April 25, 2019: Analytica Chimica Acta
Nina Denver, Shazia Khan, Ioannis Stasinopoulos, Colin Church, Natalie Zm Homer, Margaret R MacLean, Ruth Andrew
Estrogens regulate many diverse biological processes in health and disease. They circulate at a wide range of concentrations in females generating several active metabolites (hydroxy and methoxyestrogens). The metabolites are assumed to be present in much lower levels and are thought to contribute to diseases such as pulmonary arterial hypertension (PAH). Estrogen metabolites are challenging to quantify in plasma and currently available immunoassays are non-specific. Here we have developed and validated a novel assay to simultaneously quantify parent estrogens and their metabolites by mass spectrometry (MS)...
April 25, 2019: Analytica Chimica Acta
Lingjun Ma, Christoph Bueschl, Rainer Schuhmacher, Andrew L Waterhouse
Quinones are key reactive electrophilic intermediates that are formed in abundance during wine oxidation and have a significant impact on wine character, altering color and flavor. They readily react with nucleophiles, such as SO2 and glutathione. Some nucleophiles have been reported to react with quinones in model wines, but many of the corresponding products have not been confirmed in real wines. Here, a stable isotope labeling approach employing 13 C6 labeled ortho-quinone was evaluated in combination with an exact-mass list of putative products...
April 25, 2019: Analytica Chimica Acta
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