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https://www.readbyqxmd.com/read/29144554/a-sensitive-colorimetric-dna-biosensor-for-specific-detection-of-the-hbv-gene-based-on-silver-coated-glass-slide-and-g-quadruplex-hemin-dnazyme
#1
Yubin Li, Sheng Liu, Qiujuan Deng, Liansheng Ling
A sensitive colorimetric DNA biosensor for specific detection of single stranded oligonucleotide (ssDNA) is proposed in this paper. The biosensor is based on silver-coated glass (SCGS) and G-quadruplex-hemin DNAzyme. Capture DNA is immobilized on the surface of SCGS by Ag-S bond. Signal DNA can be used to hybridize with the target DNA which is selected from the Hepatitis B virus(HBV) gene as target HBV DNA, and the HRP-mimicking G-quadruplex-hemin DNAzyme can be formed through the function of a guanine-rich fragment from signal DNA to catalyze the oxidation of 2,2-azinobis(3-ethylbenzothiozoline)-6-sulfonicacid (ABTS(2-) ) by H2 O2 ...
November 16, 2017: Journal of Medical Virology
https://www.readbyqxmd.com/read/29144411/nucleic-acid-aptamers-emerging-applications-in-medical-imaging-nanotechnology-neurosciences-and-drug-delivery
#2
REVIEW
Pascal Röthlisberger, Cécile Gasse, Marcel Hollenstein
Recent progresses in organic chemistry and molecular biology have allowed the emergence of numerous new applications of nucleic acids that markedly deviate from their natural functions. Particularly, DNA and RNA molecules-coined aptamers-can be brought to bind to specific targets with high affinity and selectivity. While aptamers are mainly applied as biosensors, diagnostic agents, tools in proteomics and biotechnology, and as targeted therapeutics, these chemical antibodies slowly begin to be used in other fields...
November 16, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29143760/nano-aptasensing-in-mycotoxin-analysis-recent-updates-and-progress
#3
REVIEW
Amina Rhouati, Gonca Bulbul, Usman Latif, Akhtar Hayat, Zhan-Hong Li, Jean Louis Marty
Recent years have witnessed an overwhelming integration of nanomaterials in the fabrication of biosensors. Nanomaterials have been incorporated with the objective to achieve better analytical figures of merit in terms of limit of detection, linear range, assays stability, low production cost, etc. Nanomaterials can act as immobilization support, signal amplifier, mediator and artificial enzyme label in the construction of aptasensors. We aim in this work to review the recent progress in mycotoxin analysis. This review emphasizes on the function of the different nanomaterials in aptasensors architecture...
October 28, 2017: Toxins
https://www.readbyqxmd.com/read/29143529/hexavalent-chromium-as-an-electrocatalyst-in-dna-sensing
#4
Hamid R Lotfi Zadeh Zhad, Rebecca Y Lai
We report for the first time the use of hexavalent chromium (Cr(VI)) as an electrocatalyst in electrochemical DNA sensing. For both stem-loop probe and linear probe electrochemical DNA sensors, the increase in probe rigidity upon target hybridization alters the accessibility of Cr(VI) to the methylene blue label on the surface-immobilized DNA probes. This change results in an enhancement in the electrocatalytic current when the sensors are interrogated using cyclic voltammetry at a slow scan rate. The incorporation of this electrocatalyst does not affect the normal "signal-off" sensing behavior observed in alternating current voltammetry; instead it enables simultaneous "signal-on" and "signal-off" detection of the target, while maintaining noted attributes of this class of folding- and dynamics-based sensors such as reusability and high selectivity...
November 16, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29143069/hemin-g-quadruplex-horseradish-peroxidase-mimicking-dnazyme-principle-and-biosensing-application
#5
Negar Alizadeh, Abdollah Salimi, Rahman Hallaj
Enzymes are macromolecular biological catalysts that accelerate chemical reactions. Enzyme labels are commonly used to obtain signal amplification in sensors and biosensors on the basis of reactions of some enzymes such as horseradish peroxidase (HRP). However, use of natural enzymes can encounter some challenges. Lately, nucleic acids that exhibit catalytic properties have attracted growing interest because they have certain advantages in comparison with traditional protein enzymes. DNAzymes are DNA-based catalysts, representing an important class of functional DNA, which have been widely used because of their excellent activity, programmability, signal amplification through catalytic turnover, high chemical stability, simple synthesis, and easy modification...
November 16, 2017: Advances in Biochemical Engineering/biotechnology
https://www.readbyqxmd.com/read/29143012/%C3%AE-alanine-and-n-terminal-cationic-substituents-affect-polyamide-dna-binding
#6
Beibei Liu, Shuo Wang, Karl Aston, Kevin J Koeller, Shahrzad Fanny Hakami Kermani, Carlos H Castañeda, M José Scuderi, Rensheng Luo, James K Bashkin, W David Wilson
Minor-groove binding hairpin polyamides (PAs) bind specific DNA sequences. Synthetic modifications can improve PA-DNA binding affinity and include flexible modules, such as β-alanine (β) motifs to replace pyrroles (Py), and increasing compound charge using N-terminal cationic substituents. To better understand the variations in kinetics and affinities caused by these modifications on PA-DNA interactions, a comprehensive set of PAs with different numbers and positions of β and different types of N-cationic groups was systematically designed and synthesized to bind their cognate sequence, the λB motif...
November 16, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/29142249/a-magnetoelastic-biosensor-based-on-e2-glycoprotein-for-wireless-detection-of-classical-swine-fever-virus-e2-antibody
#7
Xing Guo, Shengbo Sang, Jinyu Guo, Aoqun Jian, Qianqian Duan, Jianlong Ji, Qiang Zhang, Wendong Zhang
A wireless magnetoelastic (ME) biosensor immobilized with E2 glycoprotein was first developed to detect classical swine fever virus (CSFV) E2 antibody. The detection principle is that a sandwich complex of CSFV E2 - rabbit anti-CSFV E2 antibody - alkaline phosphatase (AP) conjugated goat anti-rabbit IgG formed on the ME sensor surface, with biocatalytic precipitation used to amplify the mass change of antigen-antibody specific binding reaction, induces a significant change in resonance frequency of the biosensor...
November 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29142199/sensorfret-a-standardless-approach-to-measuring-pixel-based-spectral-bleed-through-and-fret-efficiency-using-spectral-imaging
#8
Paul T Arsenovic, Carl R Mayer, Daniel E Conway
Fluorescence microscopy of FRET-based biosensors allow nanoscale interactions to be probed in living cells. This paper describes a novel approach to spectrally resolved fluorescence microscopy, termed sensorFRET, that enables quantitative measurement of FRET efficiency. This approach is an improvement on existing methods (FLIM, sRET, luxFRET, pFRET), as it does not require single fluorophore standards to be measured with every experiment and the acquisition is intensity independent, allowing the laser power to be optimized for varying levels of fluorophore expression...
November 15, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29141223/gradients-of-rac1-nanoclusters-support-spatial-patterns-of-rac1-signaling
#9
Amanda Remorino, Simon De Beco, Fanny Cayrac, Fahima Di Federico, Gaetan Cornilleau, Alexis Gautreau, Maria Carla Parrini, Jean-Baptiste Masson, Maxime Dahan, Mathieu Coppey
Rac1 is a small RhoGTPase switch that orchestrates actin branching in space and time and protrusion/retraction cycles of the lamellipodia at the cell front during mesenchymal migration. Biosensor imaging has revealed a graded concentration of active GTP-loaded Rac1 in protruding regions of the cell. Here, using single-molecule imaging and super-resolution microscopy, we show an additional supramolecular organization of Rac1. We find that Rac1 partitions and is immobilized into nanoclusters of 50-100 molecules each...
November 14, 2017: Cell Reports
https://www.readbyqxmd.com/read/29141140/n-heterocyclic-carbene-self-assembled-monolayers-on-gold-as-surface-plasmon-resonance-biosensors
#10
Zhijun Li, Kim A Munro, Iraklii I Ebralidze, Mina R Narouz, J Daniel Padmos, Hongxia Hao, Cathleen M Crudden, J Hugh Horton
Surface plasmon resonance (SPR)-based biosensing is a powerful tool to study the recognition processes between biomole-cules in real-time without need for labels. The use of thiol chemistry is a critical component in surface functionalization of various SPR biosensor surfaces on gold. However, its use is hampered by the high propensity for oxidation of the gold-thiol linkage even in ambient atmosphere, resulting in a short lifetime of SPR sensor chips unless strict precautions are taken. Herein, we describe an approach to overcome this limitation by employing highly robust self-assembled monolayers (SAMs) of alkylated N-heterocyclic carbenes (NHCs) on gold...
November 15, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29140678/robust-superhydrophobic-carbon-nanotubes-film-with-lotus-leaf-mimetic-multi-scale-hierarchical-structures
#11
Pengwei Wang, Tianyi Zhao, Ruixin Bian, Guangyan Wang, Huan Liu
Superhydrophobic carbon nanotubes (CNTs) films have demonstrated many fascinating performances in versatile applications, especially for those involving solid/liquid interfacial processes, because of its ability in affecting the way of the material/energy transfer at interfaces. Thus, developing superhydrophobic CNTs has attracted extensively research interests in the past decades, and it could be achieved either by surface coating of inorganic/organic low-free energy materials or by constructing micro-/nano- hierarchical structures via various complicated processes...
November 15, 2017: ACS Nano
https://www.readbyqxmd.com/read/29140309/biosensors-to-diagnose-chagas-disease-a-brief-review
#12
REVIEW
María-Isabel Rocha-Gaso, Luis-Jesús Villarreal-Gómez, Denis Beyssen, Frédéric Sarry, Marco-Antonio Reyna, Carlos-Napoleón Ibarra-Cerdeña
Chagas disease (CD), which mostly affects those living in deprived areas, has become one of Latin America's main public health problems. Effective prevention of the disease requires early diagnosis, initiation of therapy, and regular blood monitoring of the infected individual. However, the majority of the Trypanosoma cruzi infections go undiagnosed because of mild symptoms, limited access to medical attention and to a high variability in the sensitivity and specificity of diagnostic tests. Consequently, more affordable and accessible detection technologies capable of providing early diagnosis and T...
November 15, 2017: Sensors
https://www.readbyqxmd.com/read/29140285/chitosan-cyclodextrin-tpp-nanoparticles-loaded-with-quercetin-as-novel-bacterial-quorum-sensing-inhibitors
#13
Hao Thanh Nguyen, Francisco M Goycoolea
The widespread emergence of antibiotic-resistant bacteria has highlighted the urgent need of alternative therapeutic approaches for human and animal health. Targeting virulence factors that are controlled by bacterial quorum sensing (QS), seems a promising approach. The aims of this study were to generate novel nanoparticles (NPs) composed of chitosan (CS), sulfo-butyl-ether-β-cyclodextrin (Captisol(®)) and/or pentasodium tripolyphosphate using ionotropic gelation technique, and to evaluate their potential capacity to arrest QS in bacteria...
November 15, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29140281/non-contact-sensor-for-long-term-continuous-vital-signs-monitoring-a-review-on-intelligent-phased-array-doppler-sensor-design
#14
REVIEW
Travis Hall, Donald Y C Lie, Tam Q Nguyen, Jill C Mayeda, Paul E Lie, Jerry Lopez, Ron E Banister
It has been the dream of many scientists and engineers to realize a non-contact remote sensing system that can perform continuous, accurate and long-term monitoring of human vital signs as we have seen in many Sci-Fi movies. Having an intelligible sensor system that can measure and record key vital signs (such as heart rates and respiration rates) remotely and continuously without touching the patients, for example, can be an invaluable tool for physicians who need to make rapid life-and-death decisions. Such a sensor system can also effectively help physicians and patients making better informed decisions when patients' long-term vital signs data is available...
November 15, 2017: Sensors
https://www.readbyqxmd.com/read/29140090/qm-mm-simulations-identify-the-ring-opening-mechanism-of-creatininase
#15
Jitrayut Jitonnom, Joni Mujika, Marc W van der Kamp, Adrian J Mulholland
Creatininase catalyzes the conversion of creatinine (a biosensor for kidney function) to creatine via a two-step mechanism: water-addition followed by ring-opening. Water-addition is common to other known cyclic amidohydrolases, but the precise mechanism for ring-opening is still under debate. The proton donor in this step is either His178, or a water molecule bound to one of metal ions, and the roles of His178 and Glu122 are unclear. Here, the two possible reaction pathways have been fully examined by means of combined quantum mechanics/molecular mechanics simulations at the SCC-DFTB/CHARMM22 level of theory...
November 15, 2017: Biochemistry
https://www.readbyqxmd.com/read/29138950/improvement-of-amperometric-transducer-selectivity-using-nanosized-phenylenediamine-films
#16
O V Soldatkina, I S Kucherenko, V M Pyeshkova, S A Alekseev, O O Soldatkin, S V Dzyadevych
In this work, we studied the conditions of deposition of a semipermeable polyphenylenediamine (PPD)-based membrane on amperometric disk platinum electrodes. Restricting an access of interfering substances to the electrode surface, the membrane prevents their impact on the sensor operation. Two methods of membrane deposition by electropolymerization were compared-at varying potential (cyclic voltammetry) and at constant potential. The cyclic voltammetry was shown to be easier in performing and providing better properties of the membrane...
November 14, 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/29137797/fabrication-of-g-c3n4-nio-heterostructured-nanocomposite-modified-glassy-carbon-electrode-for-quercetin-biosensor
#17
S Selvarajan, A Suganthi, M Rajarajan
Herein, we report a one-pot synthesis of structurally uniform and electrochemically active graphitic carbon nitride/nickel oxide (g-C3N4/NiO) nanocomposite and an investigation on the electrocatalytic oxidation of quercetin (QR). The synthesized g-C3N4/NiO nanocomposite has uniform surface distribution, which was characterized with scanning electron microscopy (SEM). Moreover, the composition of synthesized g-C3N4/NiO nanocomposite was characterized by UV-vis-spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR spectra), BET, SEM and HRTEM...
March 2018: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/29137710/loop-mediated-isothermal-amplification-using-self-avoiding-molecular-recognition-systems-and-antarctic-thermal-sensitive-uracil-dna-glycosylase-for-detection-of-nucleic-acid-with-prevention-of-carryover-contamination
#18
Yi Wang, Dongxin Liu, Jianping Deng, Yan Wang, Jianguo Xu, Changyun Ye
Loop-mediated isothermal amplification (LAMP) is the most popular technique to amplify nucleic acid sequence without the use of temperature cycling. However, LAMP is often confounded by false-positive results, arising from interactions between (hetero-dimer) or within (self-dimerization) primers, off-target hybrids and carryover contaminants. Here, we devised a new LAMP technique that is self-avoiding molecular recognition system (SAMRS) components and antarctic thermal sensitive uracil-DNA-glycosylase (AUDG) enzyme-assisted, termed AUDG-SAMRS-LAMP...
December 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/29137708/smartphone-based-non-invasive-salivary-glucose-biosensor
#19
Anuradha Soni, Sandeep Kumar Jha
The present work deals with the development of a non-invasive optical glucose biosensor using saliva samples and a smartphone. The sensor was fabricated with a simple methodology by immobilization of Glucose oxidase enzyme along with a pH responsive dye on a filter paper based strip. The strip changes color upon reaction with glucose present in saliva and the color changes were detected using a smartphone camera through RGB profiling. This standalone biosensor showed good sensitivity and low interference while operating within 20 s response time...
December 15, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/29137198/water-based-suspensions-of-iron-oxide-nanoparticles-with-electrostatic-or-steric-stabilization-by-chitosan-fabrication-characterization-and-biocompatibility
#20
Galina V Kurlyandskaya, Larisa S Litvinova, Alexander P Safronov, Valeria V Schupletsova, Irina S Tyukova, Olga G Khaziakhmatova, Galina B Slepchenko, Kristina A Yurova, Elena G Cherempey, Nikita A Kulesh, Ricardo Andrade, Igor V Beketov, Igor A Khlusov
Present day biomedical applications, including magnetic biosensing, demand better understanding of the interactions between living systems and magnetic nanoparticles (MNPs). In this work spherical MNPs of maghemite were obtained by a highly productive laser target evaporation technique. XRD analysis confirmed the inverse spinel structure of the MNPs (space group Fd-3m). The ensemble obeyed a lognormal size distribution with the median value 26.8 nm and dispersion 0.362. Stabilized water-based suspensions were fabricated using electrostatic or steric stabilization by the natural polymer chitosan...
November 13, 2017: Sensors
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