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Aptamers

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https://www.readbyqxmd.com/read/28231553/a-reusable-aptasensor-of-thrombin-based-on-dna-machine-employing-resonance-light-scattering-technique
#1
Yining Hou, Jifeng Liu, Min Hong, Xia Li, Yanhua Ma, Qiaoli Yue, Chen-Zhong Li
The design of molecular nanodevices attracted great interest in these years. Herein, a reusable, sensitive and specific aptasensor was constructed based on an extension-contraction movement of DNA interconversion for the application of human thrombin detection. The present biosensor was based on resonance light scattering (RLS) using magnetic nanoparticles (MNPs) as the RLS probe. MNPs coated with streptavidin can combine with biotin labeled thrombin aptamers. The combined nanoparticles composite is monodispersed in aqueous medium...
February 20, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28231552/progress-and-challenges-in-electrochemiluminescent-aptasensors
#2
REVIEW
Kateryna Muzyka, Muhammad Saqib, Zhongyuan Liu, Wei Zhang, Guobao Xu
The importance of developing new diagnostic and detection technologies for the growing number of sensing challenges is rising each year. Here, we present a comprehensive and concise review on electrochemiluminescent (ECL) aptasensors by putting special emphasis on its characteristic features, advances, challenges, and applications of ECL based aptasensors. ECL is an ideal tool for constructing such sensors because of its inherent characteristics and can be easily integrated into aptamer based sensing platforms...
January 7, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28229174/characterization-of-the-specific-interaction-between-the-dna-aptamer-sgc8c-and-protein-tyrosine-kinase-7-receptors-at-the-surface-of-t-cells-by-biosensing-afm
#3
Michael Leitner, Alexandra Poturnayova, Constanze Lamprecht, Sabine Weich, Maja Snejdarkova, Ivana Karpisova, Tibor Hianik, Andreas Ebner
We studied the interaction of the specific DNA aptamer sgc8c immobilized at the AFM tip with its corresponding receptor, the protein tyrosine kinase-7 (PTK7) embedded in the membrane of acute lymphoblastic leukemia (ALL) cells (Jurkat T-cells). Performing single molecule force spectroscopy (SMFS) experiments, we showed that the aptamer sgc8c bound with high probability (38.3 ± 7.48%) and high specificity to PTK7, as demonstrated by receptor blocking experiments and through comparison with the binding behavior of a nonspecific aptamer...
February 22, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28225598/novel-aptasensor-platform-based-on-ratiometric-surface-enhanced-raman-spectroscopy
#4
Yan Wu, Fubing Xiao, Zhaoyang Wu, Ruqin Yu
A novel aptasensor platform has been developed for quantitative detection of adenosine triphosphate (ATP) based on a ratiometric surface-enhanced Raman scattering (SERS) strategy. The thiolated 3'-Rox-labeled complementary DNA (cDNA) is first immobilized on the gold nanoparticle (AuNP) surface and then hybridizes with the 3'-Cy5-labeled ATP-binding aptamer probe (Cy5-aptamer) to form a rigid double-stranded DNA (dsDNA), in which the Cy5 and Rox Raman labels are used to produce the ratiometric Raman signals...
February 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28225108/an-integrated-perspective-on-rna-aptamer-ligand-recognition-models-clearing-muddy-waters
#5
K McCluskey, J Carlos Penedo
Riboswitches are short RNA motifs that sensitively and selectively bind cognate ligands to modulate gene expression. Like protein receptor-ligand pairs, their binding dynamics are traditionally categorized as following one of two paradigmatic mechanisms: conformational selection and induced fit. In conformational selection, ligand binding stabilizes a particular state already present in the receptor's dynamic ensemble. In induced fit, ligand-receptor interactions enable the system to overcome the energetic barrier into a previously inaccessible state...
February 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28224901/an-ssdna-library-immobilized-selex-technique-for-selection-of-an-aptamer-against-ractopamine
#6
Nuo Duan, Wenhui Gong, Shijia Wu, Zhouping Wang
An improved SELEX technique was developed for selecting aptamers against ractopamine (RAC) by immobilizing ssDNA library on the magnetic beads. After sixteen selection rounds, a highly enriched ssDNA pool was sequenced and nine families were grouped according to their homology and secondary structures analysis. One representative aptamer candidate from each family was picked out for binding affinity identification by graphene oxide (GO) adsorption platform. The aptamer RAC-6 was demonstrated as the optimal aptamer with high specificity and dissociation constant (Kd) value of 54...
April 8, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28224267/selection-of-dna-aptamers-for-extra-cellular-domain-of-human-epidermal-growth-factor-receptor-2-to-detect-her2-positive-carcinomas
#7
A Sett, B B Borthakur, U Bora
BACKGROUND: Human epidermal growth factor receptor 2 (Her2, an orphan receptor of ErbB family) is considered as an important biomarker as it plays a key role in the development and progression of aggressive types of breast, ovarian, stomach and gastric cancer. In the present study, we developed novel DNA aptamers against the extra-cellular domain (ECD) of Her2 protein for detection of Her2-positive carcinomas. METHODS: We cloned and expressed Her2-ECD protein in E...
February 21, 2017: Clinical & Translational Oncology
https://www.readbyqxmd.com/read/28223024/construction-of-a-library-of-structurally-diverse-ribonucleopeptides-with-catalytic-groups
#8
Tomoki Tamura, Shun Nakano, Eiji Nakata, Takashi Morii
Functional screening of structurally diverse libraries consisting of proteins or nucleic acids is an effective method to obtain receptors or aptamers with unique molecular recognition characteristics. However, further modification of these selected receptors to exert a newly desired function is still a challenging task. We have constructed a library of structurally diverse ribonucleopeptides (RNPs) that are modified with a catalytic group, in which the catalytic group aligns with various orientations against the ATP binding pocket of RNA subunit...
February 10, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/28222780/advanced-biosensors-for-detection-of-pathogens-related-to-livestock-and-poultry
#9
REVIEW
Jasmina Vidic, Marisa Manzano, Chung-Ming Chang, Nicole Jaffrezic-Renault
Infectious animal diseases caused by pathogenic microorganisms such as bacteria and viruses threaten the health and well-being of wildlife, livestock, and human populations, limit productivity and increase significantly economic losses to each sector. The pathogen detection is an important step for the diagnostics, successful treatment of animal infection diseases and control management in farms and field conditions. Current techniques employed to diagnose pathogens in livestock and poultry include classical plate-based methods and conventional biochemical methods as enzyme-linked immunosorbent assays (ELISA)...
February 21, 2017: Veterinary Research
https://www.readbyqxmd.com/read/28221021/probing-cellular-molecules-with-polya-based-engineered-aptamer-nanobeacon
#10
Lizhen Chen, Jie Chao, Xiangmeng Qu, Hongbo Zhang, Dan Zhu, Shao Su, Ali Aldalbahi, Lianhui Wang, Hao Pei
Adenosine triphosphate (ATP) is a central metabolite that is of critical importance in many cellular processes. The development of sensitive and selective methods for the detection of ATP level in vivo is crucial in diagnostic and theranostic applications. In this work, we have developed a polyA-based aptamer nanobeacon (PAaptNB) with improved efficiency and speed of ATP analysis. We found that the dissociation constants and competitive binding kinetics of the PAaptNB could be programmably regulated by adjusting the polyA length...
February 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28220811/aptamers-for-respiratory-syncytial-virus-detection
#11
Krisztina Percze, Zoltán Szakács, Éva Scholz, Judit András, Zsuzsanna Szeitner, Corné H van den Kieboom, Gerben Ferwerda, Marien I de Jonge, Róbert E Gyurcsányi, Tamás Mészáros
The identification of the infectious agents is pivotal for appropriate care of patients with viral diseases. Current viral diagnostics rely on selective detection of viral nucleic acid or protein components. In general, detection of proteins rather than nucleic acids is technically more suitable for rapid tests. However, protein-based virus identification methods depend on antibodies limiting the practical applicability of these approaches. Aptamers rival antibodies in target selectivity and binding affinity, and excel in terms of robustness and cost of synthesis...
February 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28220694/selective-fluorogenic-sensing-of-as-iii-using-aptamer-capped-nanomaterials
#12
Mar Oroval, Carmen Coll, Andrea Bernardos, María Dolores Marcos, Ramon Martinez-Manez, Dmitry G Shchukin, Felix Sancenón
Organic-inorganic hybrid nanomaterials offer extremely valuable tools for monitoring many types of analytes in in solution. Within this framework, aptamer-based nanomaterials for heavy metal detection are still very scarce. Herein, a novel sensing nanoprobe for the selective and sensitive detection of As(III) based on the combination of aptamers with mesoporous silica nanoparticles has been developed. The efficiency of the sensor is demonstrated in environmental conditions, showing a great potential in As(III) monitoring assays...
February 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28220154/dna-display-of-folded-rna-libraries-enabling-rna-selex-without-reverse-transcription
#13
I S MacPherson, J S Temme, I J Krauss
A method for the physical attachment of folded RNA libraries to their encoding DNA is presented as a way to circumvent the reverse transcription step during systematic evolution of RNA ligands by exponential enrichment (RNA-SELEX). A DNA library is modified with one isodC base to stall T7 polymerase and a 5' "capture strand" which anneals to the nascent RNA transcript. This method is validated in a selection of RNA aptamers against human α-thrombin with dissociation constants in the low nanomolar range. This method will be useful in the discovery of RNA aptamers and ribozymes containing base modifications that make them resistant to accurate reverse transcription...
February 21, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28219246/dna-generated-electric-current-biosensor
#14
Lanshuang Hu, Shengqiang Hu, Linyan Guo, Congcong Shen, Minghui Yang, Avraham Rasooly
In addition to its primary function as a genetic material, deoxyribonucleic acid (DNA) is also a potential biologic energy source for molecular electronics. For the first time, we demonstrate that DNA can generate a redox electric current. As an example of this new functionality, DNA generated redox current was used for electrochemical detection of human epidermal growth factor receptor 2 (HER2), a clinically important breast cancer biomarker. To induce redox current, the phosphate of the single stranded DNA aptamer backbone was reacted with molybdate to form redox molybdophosphate precipitate and generate an electrochemical current of ∼16...
February 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28218835/selection-of-2-fluoro-modified-aptamers-with-optimized-properties
#15
Deepak Thirunavukarasu, Tingjian Chen, Zhixia Liu, Narupat Hongdilokkul, Floyd E Romesberg
RNA or single-stranded DNA aptamers with 2'-F pyrimidines have been pursued to increase resistance to nucleases, and while it seems likely that these and other modifications, including the modification of purines, could be used to optimize additional properties, this has been much less explored because such aptamers are challenging to discover. Using a thermostable DNA polymerase, SFM4-3, which was previously evolved to accept nucleotides with 2'-modifications, we now report the selection of 2'-F purine aptamers that bind human neutrophil elastase (HNE)...
February 20, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28214746/a-magnetite-pmaa-nanospheres-targeting-sers-aptasensor-for-tetracycline-sensing-using-mercapto-molecules-embedded-core-shell-nanoparticles-for-signal-amplification
#16
Huanhuan Li, Quansheng Chen, Md Mehedi Hassan, Xiaoxing Chen, Qin Ouyang, Zhiming Guo, Jiewen Zhao
Surface-enhanced Raman scattering (SERS) biosensors have promising potential in the field of antibiotics detection because of their ultrahigh detection sensitivity. This paper reports a rapid and sensitive SERS-based magnetic nanospheres-targeting strategy for sensing tetracycline (TTC) using aptamer-conjugated magnetite colloid nanocrystal clusters (MCNCs)-polymethacrylic acid (PMAA) magnetic nanospheres (MNs) as the recognition and the Au/PATP/SiO2 (APS) as the labels. Initially, MNs were fabricated and conjugated with the aptamers through condensation reaction...
February 7, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28213264/a-novel-electrochemical-biosensor-based-on-polyadenine-modified-aptamer-for-label-free-and-ultrasensitive-detection-of-human-breast-cancer-cells
#17
Kun Wang, Meng-Qi He, Fu-Heng Zhai, Rong-Huan He, Yong-Liang Yu
Simple, rapid, sensitive, and specific detection of cancer cells plays a pivotal role in the diagnosis and prognosis of cancer. A sandwich electrochemical biosensor was developed based on polyadenine (polydA)-aptamer modified gold electrode (GE) and polydA-aptamer functionalized gold nanoparticles/graphene oxide (AuNPs/GO) hybrid for the label-free and selective detection of breast cancer cells (MCF-7) via a differential pulse voltammetry (DPV) technique. Due to the intrinsic affinity between multiple consecutive adenines of polydA sequences and gold, polydA modified aptamer instead of thiol terminated aptamer was immobilized on the surface of GE and AuNPs/GO...
May 1, 2017: Talanta
https://www.readbyqxmd.com/read/28213221/a-novel-fluorescent-aptasensor-for-ultrasensitive-detection-of-microcystin-lr-based-on-single-walled-carbon-nanotubes-and-dapoxyl
#18
Seyed Mohammad Taghdisi, Noor Mohammad Danesh, Mohammad Ramezani, Narjes Ghows, Seyed Ali Mousavi Shaegh, Khalil Abnous
To assure water safety and protect human health, precise and simple analytical approaches are highly desired to determine low concentrations of microcystin-leucine-arginine (MC-LR), a toxin, in both water and serum samples. Herein, a simple, rapid and accurate aptamer-based fluorescent sensor was used for selective recognition of MC-LR, based on single-walled carbon nanotubes (SWNTs) as immobilizers, dapoxyl as a fluorescent dye, DAP-10 as a specific aptamer for dapoxyl and unmodified MC-LR aptamer (Apt) as a sensing ligand...
May 1, 2017: Talanta
https://www.readbyqxmd.com/read/28211680/two-way-gold-nanoparticle-label-free-sensing-of-specific-sequence-and-small-molecule-targets-using-switchable-concatemers
#19
Longjiao Zhu, Xiangli Shao, Yunbo Luo, Kunlun Huang, Wentao Xu
A two-way colorimetric biosensor based on unmodified gold nanoparticles (GNPs) and a switchable double-stranded DNA (dsDNA) concatemer have been demonstrated. Two hairpin probes (H1&H2) were first designed that provided the fuels to assemble the dsDNA concatemers via hybridization chain reaction (HCR). A functional hairpin (FH) was rationally designed to recognize the target sequences. All the hairpins contained single-stranded DNA (ssDNA) loop and sticky-ends to prevent GNPs from salt-induced aggregation. In the presence of target sequence, the capture probe blocked in the FH recognizes the target to form a duplex DNA, which causes the release of the initiator probe by FH conformational change...
February 17, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28211299/comparison-of-biodistribution-profile-of-monoclonal-antibodies-nanoparticles-and-aptamers-in-rats-with-breast-cancer
#20
Cristal Cerqueira-Coutinho, Sotiris Missailidis, Jéssica Alessandra-Perini, Daniel Escorsim Machado, Jamila Alessandra Perini, Ralph Santos-Oliveira
The use of monoclonal antibodies and aptamers is growing every single day, as the use of nanoparticle systems. Although most of the products are under investigation, there are a few commercialized products available at the market, for human consume. In this study, we have compared three formulations (aptamer anti-MUC1, monoclonal antibody - Trastuzumab and monoclonal antibodies nanoparticles - PLA/PVA/MMT trastuzumab) to identify their profile as also to understand their behavior into an alive biological system...
May 2017: Artificial Cells, Nanomedicine, and Biotechnology
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