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Dna aptamer

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https://www.readbyqxmd.com/read/28238787/aptamer-based-liposomes-improve-specific-drug-loading-and-release
#1
Kevin Plourde, Rabeb Mouna Derbali, Arnaud Desrosiers, Céline Dubath, Alexis Vallée-Bélisle, Jeanne Leblond
Aptamer technology has shown much promise in cancer therapeutics for its targeting abilities. However, its potential to improve drug loading and release from nanocarriers has not been thoroughly explored. In this study, we employed drug-binding aptamers to actively load drugs into liposomes. We designed a series of DNA aptamer sequences specific to doxorubicin, displaying multiple binding sites and various binding affinities. The binding ability of aptamers was preserved when incorporated into cationic liposomes, binding up to 15equivalents of doxorubicin per aptamer, therefore drawing the drug into liposomes...
February 23, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/28237901/detection-of-bisphenol-a-using-palm-size-nanoaptamer-analyzer
#2
Hyun Jeong Lim, Beelee Chua, Ahjeong Son
We have demonstrated a palm-size NanoAptamer analyzer capable of detecting bisphenol A (BPA) at environmentally relevant concentrations (<1ng/mL or ppb). It is designed for performing reaction and fluorescence measurement on single cuvette sample. Modified NanoGene assay was used as the sensing mechanism where signaling DNA and QD655 was tethered to QD565 and magnetic bead via the aptamer. Aptamer affinity with BPA resulted in the release of the signaling DNA and QD655 from the complex and hence corresponding decrease in QD655 fluorescence measurement signal...
February 21, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28237255/high-affinity-truncated-dna-aptamers-for-the-development-of-fluorescence-based-progesterone-biosensors
#3
Hani Alhadrami, Raja Chinnappan, Shimaa Eissa, Anas Abdel Rahamn, Mohammed Zourob
Aptamers have shown a number of potential applications in sensing and therapeutic due to the high affinity and specificity towards their target molecules. Not all the nucleotides in the full length aptamers are involved in the binding with their targets. The non-binding domain of the aptamer may affect the binding affinity of the aptamer-target complex. Mapping the aptamer binding region could increase the affinity and the specificity. In this paper, we designed aptamer-based fluorescence sensors from a truncated progesterone (P4) aptamer...
February 22, 2017: Analytical Biochemistry
https://www.readbyqxmd.com/read/28231553/a-reusable-aptasensor-of-thrombin-based-on-dna-machine-employing-resonance-light-scattering-technique
#4
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/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
#5
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
#6
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/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/28222780/advanced-biosensors-for-detection-of-pathogens-related-to-livestock-and-poultry
#8
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/28220154/dna-display-of-folded-rna-libraries-enabling-rna-selex-without-reverse-transcription
#9
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
#10
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
#11
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
#12
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/28211680/two-way-gold-nanoparticle-label-free-sensing-of-specific-sequence-and-small-molecule-targets-using-switchable-concatemers
#13
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/28208296/ultrasensitive-self-powered-aptasensor-based-on-enzyme-biofuel-cell-and-dna-bioconjugate-a-facile-and-powerful-tool-for-antibiotic-residue-detection
#14
Panpan Gai, Chengcheng Gu, Ting Hou, Feng Li
Herein, we reported a novel ultrasensitive one-compartment enzyme biofuel cells (EBFCs)-based self-powered aptasensing platform for antibiotic residue detection. By taking full advantage of the unique features of both EBFCs-based self-powered sensors and aptamers, the as-proposed aptasensing platform has the merits of simple instrumentation, anti-interference ability, high selectivity, and low cost. In this study, DNA bioconjugate, i.e., SiO2@gold nanoparticles-complementary strand of aptamer (SiO2@AuNPs-csDNA), was elaborately designed and played a key role in blocking the mass transport of glucose to the bioanode...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28207249/convection-driven-pull-down-assays-in-nanoliter-droplets-using-scaffolded-aptamers
#15
Xiangmeng Qu, Hongbo Zhang, Hong Chen, Ali Aldalbahi, Li Li, Yang Tian, David A Weitz, Hao Pei
One of the great challenges in cellular studies is to develop a rapid and biocompatible analytical tool for single-cell analysis. We report a rapid, DNA nanostructure-supported aptamer pull-down (DNaPull) assay under convective flux in a glass capillary for analyzing contents of droplets with nano or picoliter volumes. We have demonstrated that the scaffolded aptamer can greatly improve the efficiency of target molecules' pull-down. The convective flux enables complete reaction in less than 5 min, which is an 18-fold improvement compared to purely diffusive flux (traditional model of stationary case)...
February 16, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28193041/strand-displacement-induced-enzyme-free-amplification-for-label-free-and-separation-free-ultrasensitive-atomic-fluorescence-spectrometric-detection-of-nucleic-acids-and-proteins
#16
Piaopiao Chen, Peng Wu, Yuxiang Zhang, Junbo Chen, Xiaoming Jiang, Chengbin Zheng, Xiandeng Hou
In previous work, we have developed a simple strategy for a label-free and separation-free bioassay for target DNA and protein, with the limit of detection at the nM level only. Herein, taking advantage of atomic fluorescence spectrometric detection of metal ions and amplification of DNA, a label-free and separation-free ultrasensitive homogeneous DNA analytical platform for target DNA and protein detection was developed on the basis of an enzyme-free strand displacement signal amplification strategy for dramatically improved detectability...
December 20, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/28192929/tracing-the-therapeutic-process-of-targeted-aptamer-drug-conjugate-on-cancer-cells-by-surface-enhanced-raman-scattering-spectroscopy
#17
Rong Deng, Huixin Qu, Lijia Liang, Jing Zhang, Biying Zhang, Dianshuai Huang, Shuping Xu, Chongyang Liang, Weiqing Xu
Targeted delivery of chemotherapeutic agents to pathology areas can improve drug efficiency and reduce serious side effects on normal regions. However, their treatment mechanism on cells or cell nuclei is still mysterious due to the lack of in situ characterization methods. In this paper, the specific diagnosis and treatment processes of a targeted antitumor agent (doxorubicin, Dox) functionalized aptamer complex (TLS11a-GC-Dox) toward HepG2 cells, a human hepatocellular carcinoma cell line, were tracked in real time by the surface-enhanced Raman scattering (SERS) spectroscopic technique and dark-field imaging with the assistance of gold nanorod-based nuclear targeted probes, which possess remarkable SERS enhancement ability, specific targeting, and excellent biological compatibility...
February 13, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28191845/self-assembled-nanoconstructs-modified-with-amplified-aptamers-inhibited-tumor-growth-and-retinal-vascular-hyperpermeability-via-vegf-capturing
#18
Jihyun Lee, Byung Joo Lee, Yeong Mi Lee, Hansoo Park, Jeong Hun Kim, Won Jong Kim
Here, nanoconstructs consisting of a DNA-amplified aptamer with a biocompatible polymer backbone for capturing target biomolecules are presented. First, the polymer-DNA nanoconstructs were prepared by hybridization of two complementary single-stranded DNAs that were each conjugated to a dextran polymer backbone. The designed polymer-DNA amplified aptamer nanoconstructs (PA-aNCs) were then prepared by utilizing polymer-DNA nanoconstructs conjugated with an aptamer (PA-NCs) using a rolling circle amplification reaction to amplify the aptamer...
February 13, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28190829/a-label-free-and-turn-on-fluorescence-strategy-for-kanamycin-detection-based-on-the-nmm-g-quadruplex-structure
#19
Hualin Yang, Qinghua Wu, Dongxiao Su, Yun Wang, Li Li, Xingping Zhang
In the present work, a simple design of a "label-free" fluorescence method for kanamycin was developed and explored based on a specific DNA aptamer as a recognizer and a NMM/G-quadruplex DNA system as a reporter. The titration experiment showed a linear detection range of 0.5 to 100 nM with a low detection limit of 0.5 nM. It also showed excellent selectivity in a selectivity experiment. It was then successfully employed to detect kanamycin in milk with a excellent reliability.
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
https://www.readbyqxmd.com/read/28188007/volumetric-contributions-of-loop-regions-of-g-quadruplex-dna-to-the-formation-of-the-tertiary-structure
#20
Shuntaro Takahashi, Naoki Sugimoto
DNA guanine-quadruplexes (G-quadruplexes) are unique DNA structures formed by guanine-rich sequences. The loop regions of G-quadruplexes play key roles in stability and topology of G-quadruplexes. Here, we investigated volumetric changes induced by pressure in the folding of the G-quadruplex formed by the thrombin binding aptamer (TBA) with mutations within the loop regions. The change of partial molar volume in the transition from coil to G-quadruplex, ∆Vtr, of TBA with a mutation from T to A in the 5' most loop (TBA T3A) was 75...
February 6, 2017: Biophysical Chemistry
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