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Dna aptamer

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https://www.readbyqxmd.com/read/28743084/graphene-oxide-gold-nanorods-based-multiple-assisted-electrochemiluminescence-signal-amplification-strategy-for-sensitive-detection-of-prostate-specific-antigen
#1
Jun-Tao Cao, Jiu-Jun Yang, Li-Zhen Zhao, Yu-Ling Wang, Hui Wang, Yan-Ming Liu, Shu-Hui Ma
A novel and competitive electrochemiluminescence (ECL) aptasensor for prostate specific antigen (PSA) assay was constructed using gold nanorods functionalized graphene oxide (GO@AuNRs) multilabeled with glucose oxidase (GOD) and streptavidin (SA) toward luminol-based ECL system. A strong initial ECL signal was achieved by electrodeposited gold (DpAu) on the electrode because of gold nanoparticles (AuNPs) motivating the luminol ECL signal. The signal probes prepared by loading GOD and SA-biotin-DNA on GO@AuNRs were used for achieving multiple signal amplification...
July 20, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28740380/inhibition-of-cell-proliferation-through-an-atp-responsive-co-delivery-system-of-doxorubicin-and-bcl-2-sirna
#2
Jianxu Zhang, Yudi Wang, Jiawen Chen, Xiao Liang, Haobo Han, Yan Yang, Quanshun Li, Yanbo Wang
Herein, DNA duplex was constructed through the hybridization of adenosine triphosphate (ATP)-responsive aptamer and its cDNA in which GC-rich motif could be used to load doxorubicin (DOX), and then, cationic polymer PEI25K was used as a carrier to simultaneously condense DOX-Duplex and Bcl-2 siRNA to prepare the ternary nanocomplex polyethylenimine (PEI)/DOX-Duplex/siRNA. The ATP concentration gradient between the cytosol and extracellular environment could achieve the stable loading of DOX in duplex and the rapid drug release in an ATP-responsive manner...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28738645/competitive-fluorescence-anisotropy-polarization-assay-for-atp-using-aptamer-as-affinity-ligand-and-dye-labeled-atp-as-fluorescence-tracer
#3
Yapiao Li, Linlin Sun, Qiang Zhao
We developed an aptamer-based competitive fluorescence anisotropy (FA)/fluorescence polarization (FP) assay for adenosine triphosphate (ATP). Different from the traditional fluorescence polarization immunoassays for small molecules, here DNA aptamer against ATP was used as affinity ligand, and tetramethylrhodamine (TMR) labeled ATP served as fluorescent tracer. The binding between TMR-labeled ATP and aptamer gave large FA due to molecular volume increase and restricted rotation of the dye-labeled ATP. When ATP was added in solution, ATP competitively displaced the TMR-labeled ATP from aptamer affinity complex, causing decrease of FA of TMR-labeled ATP...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28738618/high-sensitivity-surface-plasmon-resonance-biosensor-for-detection-of-microrna-and-small-molecule-based-on-graphene-oxide-gold-nanoparticles-composites
#4
Qing Li, Qing Wang, Xiaohai Yang, Kemin Wang, Hua Zhang, Wenyan Nie
A versatile and sensitive surface plasmon resonance (SPR) biosensor based on two layers of graphene oxide-gold nanoparticles (GO-AuNPs) composites was designed for the detection of microRNA (miRNA) and small molecule adenosine. The bottom layer, which acted as a functionalized substrate on the sensor chip, provided a high specific surface area convenient for the immobilization of capture DNA molecules. The upper layer served as a signal-amplification element. By employing these two layers of GO-AuNPs composites, the dual amplification strategy was achieved so that a measurement of miRNA-141 with a detection limit of 0...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28735043/a-high-sensitivity-electrochemical-aptasensor-of-carcinoembryonic-antigen-based-on-graphene-quantum-dots-ionic-liquid-nafion-nanomatrix-and-dnazyme-assisted-signal-amplification-strategy
#5
Jing-Yi Huang, Lang Zhao, Wan Lei, Wei Wen, Yi-Jia Wang, Ting Bao, Hua-Yu Xiong, Xiu-Hua Zhang, Sheng-Fu Wang
In this work, we have developed an electrochemical aptasensor for high-sensitivity determination of carcinoembryonic antigen (CEA) based on lead ion (Pb(2+))-dependent DNAzyme-assisted signal amplification and graphene quantum dot-ionic liquid-nafion (GQDs-IL-NF) composite film. We designed hairpin DNA containing CEA-specific aptamers and DNAzyme chains. In the presence of CEA, hairpin DNA recognized the target and performed a DNAzyme-assisted signal amplification reaction to yield a large number of single-stranded DNA...
July 15, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28732346/multiplexed-aptasensor-for-simultaneous-detection-of-carcinoembryonic-antigen-and-mucin-1-based-on-metal-ion-electrochemical-labels-and-ru-nh3-6-3-electronic-wires
#6
Chao Ma, Haiyun Liu, Lina Zhang, Hao Li, Mei Yan, Xianrang Song, Jinghua Yu
In this paper, a dual-target electrochemical aptasensor has been developed for simultaneous detection of carcinoembryonic antigen and mucin-1 based on metal ion electrochemical labels and Ru(NH3)6(3+) electronic wires. When targets are present, the interaction between targets and their respective aptamers leads to the dissociation of double-strand DNA because the targets have higher affinity to its aptamer than the complementary strand. And the qualitative and quantitative analyses of the two targets are realized by the differential pulse voltammetry (DPV) peaks generated by metal ion electrochemical labels...
July 13, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28731107/a-fluorescent-turn-on-nanoprobe-for-simultaneous-visualization-of-dual-targets-involved-in-cell-apoptosis-and-drug-screening-in-living-cells
#7
Xiaolong Zhang, Naishun Liao, Geng Chen, Aixian Zheng, Yongyi Zeng, Xiaolong Liu, Jingfeng Liu
Herein, a novel dual-responsive two-color fluorescent nanoprobe has been designed for the fluorescence activation imaging of cell apoptosis in living cells. The nanoprobe consists of a gold nanoparticle core functionalized with a dense layer of DNA aptamers and peptides, which shows high affinity and specific response to cytochrome c (Cyt c) and caspase-3, respectively. The formation of the aptamer-Cyt c complex and the cleavage of the specific peptide by caspase-3 can liberate the dye labelled aptamers and peptides from the surface of gold nanoparticles, and then recover their fluorescence...
July 21, 2017: Nanoscale
https://www.readbyqxmd.com/read/28730439/design-and-preparation-of-aptamer-sirna-chimeras-asics-for-targeted-cancer-therapy
#8
Sven Kruspe, Paloma H Giangrande
Conjugation of cell-internalizing DNA or RNA aptamers to tumor-suppressing siRNAs represents a novel promising approach for cancer therapy. Here we describe how to employ RNA aptamers that bind to cell surface receptors as carriers for cell-targeted siRNA (or miRNA) delivery. This protocol was optimized to improve the efficiency of the aptamer-siRNA/miRNA conjugates and facilitate its implementation in most molecular biology labs. The single working steps include (1) outlining the optimal sequences of the RNA strands bearing the aptamer and siRNA sequence, for which further (2) a dsDNA template is synthesized and then (3) transcribed into an RNA that will be (4) folded and annealed to a chemically synthesized siRNA complementary strand...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28730438/x-aptamer-selection-and-validation
#9
Ganesh L Lokesh, Hongyu Wang, Curtis H Lam, Varatharasa Thiviyanathan, Nancy Ward, David G Gorenstein, David E Volk
Aptamers and second generation analogs, such as X-Aptamers (XAs), SOMAmers, locked nucleic acids (LNAs), and others are increasingly being used for molecular pathway targeting, biomarker discovery, or disease diagnosis by interacting with protein targets on the surface of cells or in solution. Such targeting is being used for imaging, diagnostic evaluation, interference of protein function, or delivery of therapeutic agents. Selection of aptamers using the original SELEX method is cumbersome and time-consuming, often requiring 10-15 rounds of selection, and provides aptamers with a limited number of functional groups, namely four bases of DNA or RNA, although newer SELEX methods have increased this diversity...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28728009/bridged-rebar-graphene-functionalized-aptasensor-for-pathogenic-e-coli-o78-k80-h11-detection
#10
Harmanjit Kaur, Munish Shorie, Manju Sharma, Ashok K Ganguli, Priyanka Sabherwal
We report a novel fabrication method of functionalised Bridged Rebar Graphene (BRG) onto newly designed nanostructured aptasensor for label free impedimetric sensing of pathogenic bacteria E. coli O78:K80:H11. The chemical facilitated unscrolling of MWCNT and subsequent bridging with terephthalaldehyde (TPA) to form 3D-hierarchical BRG nanoconstruct exhibited synergistic effect by combining enhanced electrical properties and facile chemical functionality for stable bio-interface. The bacteria-DNA interactions were captured on BRG nanostructured electrode by using specific anti-E...
July 5, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28723179/multifunctional-nanofibers-for-specific-purification-and-release-of-ctcs
#11
Zhili Wang, Na Sun, Min Liu, Yi Cao, Kewei Wang, Jine Wang, Renjun Pei
Recovering pure and viable circulating tumor cells (CTCs) from blood has been a challenging task for molecular characterization and functional analysis, which has attracted wide attention these days. Herein, we fabricate a thermoresponsive chitosan nanofiber substrate to effectively capture, purify, and release the target cancer cells, assisted by PNIPAAm brushes and DNA hybridization. The PNIPAAm brushes are designed to enable WBCs to detach from aptamer-PNIPAAm-chitosan-nanofiber (aptamer-P-CNFs) surfaces during the conformational transition...
April 28, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723133/label-free-nanopore-biosensor-for-rapid-and-highly-sensitive-cocaine-detection-in-complex-biological-fluids
#12
Sana Rauf, Ling Zhang, Asghar Ali, Yang Liu, Jinghong Li
Detection of very low amounts of illicit drugs such as cocaine in clinical fluids like serum continues to be important for many areas in the fight against drug trafficking. Herein, we constructed a label-free nanopore biosensor for rapid and highly sensitive detection of cocaine in human serum and saliva samples based on target-induced strand release strategy. In this bioassay, an aptamer for cocaine was prehybridized with a short complementary DNA. Owing to cocaine specific binding with aptamer, the short DNA strand was displaced from aptamer and translocation of this output DNA through α-hemolysin nanopore generated distinct spike-like current blockages...
February 24, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28722429/detection-of-k-efflux-from-stimulated-cortical-neurons-by-an-aptamer-modified-silicon-nanowire-field-effect-transistor
#13
Ankur Anand, Chia-Rung Liu, Ai-Chuan Chou, Wan-Hsuan Hsu, Rajesh Kumar Ulaganathan, Yi-Cheng Lin, Chi-An Dai, Fan-Gang Tseng, Chien-Yuan Pan, Yit-Tsong Chen
The concentration gradient of K(+) across the cell membrane of a neuron determines its resting potential and cell excitability. During neurotransmission, the efflux of K(+) from the cell via various channels will not only decrease the intracellular K(+) content but also elevate the extracellular K(+) concentration. However, it is not clear to what extent this change could be. In this study, we developed a multiple-parallel-connected silicon nanowire field-effect transistor (SiNW-FET) modified with K(+)-specific DNA-aptamers (aptamer/SiNW-FET) for the real-time detection of the K(+) efflux from cultured cortical neurons...
January 27, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28721653/comparison-of-flow-cytometry-and-elasa-for-screening-of-proper-candidate-aptamer-in-cell-selex-pool
#14
Maryam Sadat Nabavinia, Fahimeh Charbgoo, Mona Alibolandi, Fatemeh Mosaffa, Aida Gholoobi, Mohammad Ramezani, Khalil Abnous
Aptamers are single-stranded RNA or DNA, which bind to their target with high affinity and specificity. Method of isolating aptamers against cell surface protein is called cell-SELEX. Common approach for monitoring cell-SELEX developed aptamers is flow cytometry. Since flow cytometry is costly and requires sophisticated equipments, we suggested implementing easy access, high throughput enzyme-link apta-sorbent assay test (ELASA) to confirm the specificity of aptamers selected through cell-SELEX process. In this regard, we compared ELASA and flow cytometry techniques in order to screen potent candidate aptamers against A2780 Rcis cell line, which were selected by cell-SELEX...
July 19, 2017: Applied Biochemistry and Biotechnology
https://www.readbyqxmd.com/read/28718456/graphene-oxide-and-dna-aptamer-based-sub-nanomolar-potassium-detecting-optical-nanosensor
#15
Debopam Datta, Ketaki Sarkar, Souvik Mukherjee, Xenia Meshik, Michael A Stroscio, Mitra Dutta
Quantum-dot (QD) based nanosensors are frequently used by researchers to detect small molecules, ions and different biomolecules. In this article, we present a sensor complex/system comprised of deoxyribonucleic acid (DNA) aptamer, gold nanoparticle and semiconductor QD, attached to a graphene oxide (GO) flake for detection of potassium. As reported herein, it is demonstrated that QD-aptamer-quencher nanosensor functions even when tethered to GO, opening the way to future applications where sensing can be accomplished simultaneously with other previously demonstrated applications of GO such as serving as a nanocarrier for drug delivery...
August 11, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28718373/screening-of-specific-nucleic-acid-aptamers-binding-tumor-markers-in-the-serum-of-the-lung-cancer-patients-and-identification-of-their-activities
#16
Kun Li, Chen-Lin Xiu, Li-Ming Gao, Hua-Gang Liang, Shu-Feng Xu, Ming Shi, Jian Li, Zhi-Wei Liu
Lung cancer is by far the leading cause of cancer death in the world. Despite the improvements in diagnostic methods, the status of early detection was not achieved. So, a new diagnostic method is needed. The aim of this study is to obtain the highly specific nucleic acid aptamers with strong affinity to tumor markers in the serum of the lung cancer patients for targeting the serum. Aptamers specifically binding to tumor markers in the serum of the lung cancer patients were screened from the random single-stranded DNA library with agarose beads as supports and the serum as a target by target-substituting subtractive SELEX technique and real-time quantitative polymerase chain reaction technique...
July 2017: Tumour Biology: the Journal of the International Society for Oncodevelopmental Biology and Medicine
https://www.readbyqxmd.com/read/28709900/development-of-carbon-graphene-based-aptamer-biosensor-for-en2-protein-detection
#17
Kalpana Settu, Jen-Tsai Liu, Ching-Jung Chen, Jang-Zern Tsai
In this study, we developed a screen-printed carbon-graphene-based electrochemical biosensor for EN2 protein detection. The engrailed-2 (EN2) protein, a biomarker for prostate cancer, is known to be a strong binder to a specific DNA sequence (5'-TAATTA-3') to regulate transcription. To take advantage of this intrinsic property, aptamer probes with TAATTA sequence was immobilized onto the screen-printed carbon-graphene electrode surface via EDC-NHS coupling approach. Cyclic voltammetry (CV) of the electrochemical measurement technique was employed for the quantitative detection of EN2 protein...
July 11, 2017: Analytical Biochemistry
https://www.readbyqxmd.com/read/28709088/integrated-amplified-aptasensor-with-in-situ-precise-preparation-of-copper-nanoclusters-for-ultrasensitive-electrochemical-detection-of-microrna-21
#18
Yijia Wang, Xinying Zhang, Lang Zhao, Ting Bao, Wei Wen, Xiuhua Zhang, Shengfu Wang
MicroRNA 21 (MIR21) has garnered much attention in recent years as an important disease biomarker. The detection of it in human system shows great significance for the healthy evaluation and major diseases early detection. Herein, a novel approach tactfully manipulates the in-situ precise preparation of copper nanoclusters on overlapping Y-shaped ds-DNA for MIR21 analysis were developed in the proposed integrated aptasensor. In the presence of target MIR21, overlapping Y-shaped ds-DNA was constructed on electrode...
July 5, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28707670/-enzymatic-synthesis-of-high-modified-dna
#19
A V Chudinov, Y Y Kiseleva, V E Kuznetsov, V E Shershov, M A Spitsyn, T O Guseinov, S A Lapa, E N Timofeev, A I Archakov, A V Lisitsa, S P Radko, A S Zasedatelev
Here, we describe the synthesis and purification of six deoxyuridine triphosphate derivatives that contain protein-like functional groups and alkene linkers of various lengths. Using KOD XL and Deep Vent polymerases, these derivatives have been incorporated into single-stranded DNA, achieving a high degree of DNA modification. These polymerases are able to utilize highly modified DNA strands as templates for synthesizing unmodified DNA. The synthesized deoxyuridine triphosphate derivatives are promising as substrates for producing modified aptamers to various target proteins using, e...
May 2017: Molekuliarnaia Biologiia
https://www.readbyqxmd.com/read/28704034/unique-thermal-stability-of-unnatural-hydrophobic-ds-bases-in-double-stranded-dnas
#20
Michiko Kimoto, Ichiro Hirao
Genetic alphabet expansion technology, the introduction of unnatural bases or base pairs into replicable DNA, has rapidly advanced as a new synthetic biology area. A hydrophobic unnatural base pair between 7-(2-thienyl)imidazo[4,5-b]pyridine (Ds) and 2-nitro-4-propynylpyrrole (Px) exhibited high fidelity as a third base pair in PCR. SELEX methods using the Ds-Px pair enabled high-affinity DNA aptamer generation, and introducing a few Ds bases into DNA aptamers extremely augmented their affinities and selectivities to target proteins...
July 13, 2017: ACS Synthetic Biology
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