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Quentin Avenas, Julien Moreau, Marion Costella, Arbi Maalaoui, Abdelkader Souifi, Paul Charette, Julien Marchalot, Marie Frénéa-Robin, Michael Canva
Analytes concentration techniques are being developed with the appealing expectation to boost the performance of biosensors. One promising method lies in the use of electrokinetic forces. We present hereafter a new design for a microstructured plasmonic sensor which is obtained by conventional microfabrication techniques, and which can easily be adapted on a classical surface plasmon resonance imaging (SPRI) system without further significant modification. Dielectrophoretic trapping and electro-osmotic displacement of the targets in the scanned fluid are performed through interdigitated 200 μm wide gold electrodes that also act as the SPR-sensing substrate...
February 20, 2019: Electrophoresis
Yuanyuan Ma, Tianxiang Chen, Muhammad Zubair Iqbal, Fang Yang, Norbert Hampp, Aiguo Wu, Liqiang Luo
As a result of their advantages for superparamagnetic properties, good biocompatibility and high binding capacity, functionalized magnetic materials became widely popular over the past couple of decades, being applied on large scale in various processes of sample preparation for biomedicine. In this work we perform an in-depth review on the current progress in the field of magnetic bead separation, discussing in detail the physical basis of this process, various synthesis methods and surface modification strategies...
February 19, 2019: Electrophoresis
Yusheng Fu, Jianmin Lei, Xiao Zou, Jiuchuan Guo
In the current field of biomedical engineering, the research on implanted antennas has attracted more and more attention. This paper presents a flexible terrestrial radiating antenna with circular polarization characteristics that satisfy various requirements for biomedical implantable antennas. The new type of flexible material is adopted and a novel model is proposed. The square ground with small gap is implemented in the proposed antenna. The passive components can match the impedance and meet the requirements of the circular polarization wave...
February 19, 2019: Electrophoresis
Wei Si, Haojie Yang, Jingjie Sha, Yin Zhang, Yunfei Chen
Nanopore sensor has been developed as a promising technology for DNA sequencing at the single-base resolution. However, the discrimination of homopolymers composed of guanines from other nucleotides has not been clearly revealed due to the easily formed G-quadruplex in aqueous buffers. In this work, we report that a tiny silicon nitride nanopore was used to sieve out G tetramers to make sure only homopolymers composed of guanines could translocate through the nanopore, then the 20-nucleotide long ssDNA homopolymers could be identified and differentiated...
February 18, 2019: Electrophoresis
Pojchanun Kanitthamniyom, Yi Zhang
Magnetic digital microfluidics uses magnetic force to manipulate droplets on a Teflon-coated substrate through the added magnetic particles. To achieve a wide range of droplet manipulation, hydrophilic patterns, known as surface energy traps, are introduced onto the Teflon-coated hydrophobic substrate. However, the Teflon-coated substrate is difficult to modify because it is non-wettable, and existing techniques for patterning surface energy traps have many limitations. Inspired by the mussel adhesion mechanism, we use polydopamine, a bioinspired substance that adheres strongly to almost any materials, to pattern surface energy traps on the Teflon-coated substrate with a great ease...
February 16, 2019: Electrophoresis
Vishakha Sharma, Krupa Jani, Pavan Khosla, Erin Butler, Donald Siegel, Elisa Wurmbach
This study examined 266 individuals from various populations including African American, East Asian, South Asian, European, and mixed populations to evaluate the ForenSeq™ Signature Prep Kit Primer Mix B. Focus was placed on phenotypic and biogeographical ancestry predictions by Illumina's Universal Analysis Software (UAS). These outcomes were compared to those obtained through web-tools developed at the Erasmus Medical Center (EMC) and available from the Forensic Resource/Reference on Genetics-knowledge base (FROG-kb), as well as to eye color predictions by the 8-plex system...
February 15, 2019: Electrophoresis
Annette M Krais, Christian Kliem, Volker M Arlt, Heinz H Schmeiser
Methylating substances alter DNA by forming N3-methylthymidine (N3mT), a mutagenic base modification. To develop a sensitive analytical method for the detection of N3mT in DNA based on capillary electrophoresis with laser-induced fluorescence detection (CE-LIF), we synthesized the N3mT-3'-phosphate as a chemical standard. The limit of detection was 1.9 amol of N3mT, which corresponds to one molecule of N3mT per 1,000 normal nucleotides or 0.1%. With this method, we demonstrated that the carcinogenic nitrosamine N'-nitrosonornicotine (NNN) induced N3mT in the human lung cancer cell line A549...
February 15, 2019: Electrophoresis
Ezekiel O Adekanmbi, Jeremiah Dustin, Soumya K Srivastava
It is a common practice in insulator-based dielectrophoretic separation to use and reuse PDMS-constructed microdevice for an extended period of time while performing biological and technical replicate experiments. This is usually done to rule out any effects of device variation on separation efficiency. Ensuring that all experimental conditions remain the same is critical to the conclusion that can be drawn from such repeated experiments. One important contributing factor to the flow of materials within the device is electro-osmotic velocity, which stems from the surface condition of the device construction materials...
February 14, 2019: Electrophoresis
Zoltán-István Szabó, Róbert Ludmerczki, Béla Fiser, Béla Noszál, Gergő Tóth
Pressure-assisted stereospecific capillary electrophoresis method was developed for the determination of enantiomeric purity of the antiparkinsonian agent (R)-rasagiline. The optimized method, 50 mM glycine-HCl buffer pH 2.0, supplied with 30 mM sulfobutylether-β-cyclodextrin, at 35°C, applying 12 kV in reversed polarity, and - 8 mbar pressure (vacuum), short-end injection with -25 mbar x 2 seconds, was successful for baseline separation of rasagiline enantiomers (Rs = 3.5 ± 0.1) in a short analysis time...
February 13, 2019: Electrophoresis
Qiong Lan, Chunmei Shen, Xiaoye Jin, Yuxin Guo, Tong Xie, Chong Chen, Wei Cui, Yating Fang, Guang Yang, Bofeng Zhu
In the forensic field, ancestry-informative markers showing remarkable allele frequency discrepancies can be useful in deducing the likely ancestral origin of a person or estimating the ancestry component proportions of admixed populations or individuals. Diallelic SNPs are genetic markers commonly used for ancestry inference, but the genotyping methods of SNPs fail to fulfil the demands of cost-effectiveness and simplicity of experimental manipulation. To overcome the limitations, a 39 ancestry-informative InDels multiplex panel was developed in the present study to perform ancestry assignment of individuals from three distinct biogeographic regions (African, European, East Asian)...
February 13, 2019: Electrophoresis
Mohammad Aghaamoo, Arian Aghilinejad, Xiaolin Chen, Jie Xu
Recently, detection and analysis of circulating tumor cells (CTCs) have emerged as a promising way to diagnose cancer, study its cellular mechanism, and test or develop potential treatments. However, the rarity of CTCs among peripheral blood cells is a big challenge towards CTC detection. In addition, in cases where there is similar size range between certain types of CTCs (e.g. breast cancer cells) and white blood cells (WBCs), high-resolution techniques are needed to provide separation of cells with similar size range...
February 10, 2019: Electrophoresis
Feng-Ling Xu, Mei Ding Xi Xia, Xue Wu, Jing-Jing Zhang, Jia-Xin Xing, Jin-Feng Xuan, Jun Yao, Bao-Jie Wang
Semi-nested PCR with allele-specific (AS) primers and sequencing of mitochondrial DNA (mtDNA) were performed to analyze and interpret DNA mixtures, especially when biological materials were degraded or contained a limited amount of DNA. SNP-STR markers were available to identify the minor DNA component using AS-PCR; moreover, SNPs in mtDNA could be used when the degraded or limited amounts of DNA mixtures were not successful with SNP-STR markers. Five pairs of allele specific primers were designed based on three SNPs (G15043A, T16362C, and T16519C)...
February 10, 2019: Electrophoresis
Giovanni D'Orazio, Chiara Fanali, Alessandra Gentili, Salvatore Fanali
This work deals with the potentiality of nano liquid chromatography (Nano-LC) for the chiral separation of racemic mixture of tryptophan and some selected derivatives by using 100 μm i.d. fused silica capillary packed with teicoplanin bonded to 5 μm diol silica stationary phase. The experiments were carried out by using a cheap and laboratory-assembled nano-LC - UV system. Elution was done in an isocratic mode using a polar organic mobile phase. In order to find the optimum chiral separation of the studied enantiomers, some chromatographic experimental parameters were systematically studied and optimized...
February 6, 2019: Electrophoresis
Zhaokun Wang, Xia Wang, Shuang Li, Zhen Jiang, Xingjie Guo
In this work, a carbon nanosphere decorated by Fe3 O4 nanoparticles was prepared, characterized and used as the magnetic adsorbent. Eight commonly used chiral triazole fungicides, including penconazole, uniconazole, paclobutrazol, triazolone, tebuconazole, hexaconazole, triticonazole and epoxiconazole were extracted from two environmental water samples (river water and lake water) by magnetic solid-phase extraction, followed by the enantiomeric analysis on a Chiralpark IC column coupled with a triple quadrupole mass spectrometry to evaluate their possible stereoselective degradation occurring in the water samples...
February 6, 2019: Electrophoresis
Chu Chu, Shan Wang, Huan Zhang, Caijing Liu, Luyi Jiang, Yiping Tang, Jizhong Yan
A sensitive dispersive micro solid-phase extraction coupled with high performance liquid chromatography has been developed for preconcentration and determination of three flavonoids (quercetin, kaempferol and isorhamnetin) in complex matrix samples. Parameters that affecting extraction efficiency have been optimized. The optimal extraction conditions is using 2 μg/mL of crab shell as the sorbent, extraction for 2 min at pH 7 and then eluting with 100 μL of methanol. As a result, the method shows good linearity (R >0...
February 6, 2019: Electrophoresis
Annette M Krais, Yoon Jung Park, Guido Reifenberger, Michael Meister, Christoph Plass, Heinz H Schmeiser
A new sensitive analytical method using capillary electrophoresis with laser induced fluorescence (CE-LIF) was applied for the simultaneous detection of DNA methylation and hydroxymethylation levels in human cancers of different origin. DNA hydroxymethylation, measured as 5-hydroxymethylcytosine (5hmC) levels, was decreased in gliomas with mutation in the isocitrate dehydrogenase 1 (IDH1) gene when compared to IDH1-wildtype gliomas. Independent from IDH1 mutation, 5hmC levels were decreased in lung carcinomas when compared to normal lung tissue...
February 6, 2019: Electrophoresis
Paola Peluso, Alessandro Dessì, Roberto Dallocchio, Victor Mamane, Sergio Cossu
Liquid-phase enantioseparations have been fruitfully applied in several fields of science. Various applications along with technical and theoretical advancements contributed to increase significantly the knowledge in this area. Nowadays, chromatographic techniques, in particular HPLC on chiral stationary phase, are considered as mature technologies. In the last thirty years, CE has been also recognized as one of the most versatile technique for analytical scale separation of enantiomers. Despite the huge number of papers published in these fields, understanding mechanistic details of the stereoselective interaction between selector and selectand is still an open issue, in particular for high-molecular weight chiral selectors like polysaccharide derivatives...
February 2, 2019: Electrophoresis
Henrik Harnisch, István Ilisz, Ferenc Fülöp, Zsolt Szakonyi, Lóránd Kiss, Antal Péter, Gerhard K E Scriba
The present study investigated the separation of bicyclic β-amino acids with bicyclo[2.2.2]octane, bicyclo[3.1.1]heptane and cyclopenta[d][1,2]oxazole core structures by capillary electrophoresis using native cyclodextrins as well as neutral and charged derivatives as chiral selectors. The amino acids were derivatized with dansyl chloride to provide a UV chromophore. Separations were carried out at 20°C in a 48.5/40 cm, 50 μm fused-silica capillary at an applied voltage of 20 kV. 50 mM sodium phosphate background electrolytes pH 2...
February 1, 2019: Electrophoresis
Jonathan Cottet, Alexandre Kehren, Soufian Lasli, Harald van Lintel, François Buret, Marie Frénéa-Robin, Philippe Renaud
We present a microfluidic platform allowing dielectrophoresis-assisted formation of cell aggregates of controlled size and composition under flow conditions. When specific experimental conditions are met, negative dielectrophoresis (nDEP) allows efficient concentration of cells towards electric field minima and subsequent aggregation. This bottom-up assembly strategy offers several advantages with respect to the targeted application: first, DEP offers precise control of spatial cell organization, which can be adjusted by optimizing electrode design...
February 1, 2019: Electrophoresis
Yangye Geng, Zhen Zhu, Yingying Wang, Yiyun Wang, Shuiping Ouyang, Ke Zheng, Wenbo Ye, Yimin Fan, Zixin Wang, Dejing Pan
This work presents a microfluidic device, which was patterned with (i) microstructures for hydrodynamic capture of single particles and cells, and (ii) multiplexing microelectrodes for selective release via negative dielectrophoretic (nDEP) forces and electrical impedance measurements of immobilized samples. Computational fluid dynamics (CFD) simulations were performed to investigate the fluidic profiles within the microchannels during the hydrodynamic capture of particles and evaluate the performance of single-cell immobilization...
January 31, 2019: Electrophoresis
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