keyword
MENU ▼
Read by QxMD icon Read
search

aptamer

keyword
https://www.readbyqxmd.com/read/28211680/two-way-gold-nanoparticle-label-free-sensing-of-specific-sequence-and-small-molecule-targets-using-switchable-concatemers
#1
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
#2
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
https://www.readbyqxmd.com/read/28209633/gene-expression-control-by-bacillus-anthracis-purine-riboswitches
#3
Marion Kirchner, Sabine Schneider
In all kingdoms of life, cellular replication relies on the presence of nucleosides and nucleotides, the building blocks of nucleic acids and the main source of energy. In bacteria, the availability of metabolites sometimes directly regulates the expression of enzymes and proteins involved in purine salvage, biosynthesis and uptake through riboswitches. Riboswitches are located in bacterial mRNAs and can control gene expression by conformational changes in response to ligand binding. We have established an inverse reporter gene system in Bacillus subtilis that allows us to monitor riboswitch-controlled gene expression...
February 16, 2017: RNA
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
#4
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/28208258/tuning-the-aggregation-disaggregation-behavior-of-graphene-quantum-dots-by-structure-switching-aptamer-for-high-sensitivity-fluorescent-ochratoxin-a-sensor
#5
Song Wang, Yajun Zhang, Guangsheng Pang, Yingwei Zhang, Shaojun Guo
The design of graphene quantum dots (GQDs)-aptamer bioconjugates as the new sensing platform is very important for developing high-sensitivity fluorescent biosensors; however, achieving new bioconjugates is still a great challenge. Herein, we report the development of a new high-sensitivity fluorescent aptasensor for the detection of ochratoxin A (OTA) based on tuning aggregation/disaggregation behavior of GQDs by structure-switching aptamers. The fluorescence sensing process for OTA detection involved two key steps: (1) cDNA-aptamer (cDNA, complementary to part of the OTA aptamer) hybridization induced the aggregation of GQD (fluorescence quenching) after cDNA was added into the GQDs-aptamer bioconjugate solution, and (2) the target of OTA triggered disaggregation of GQD aggregates (fluorescence recovery)...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28207249/convection-driven-pull-down-assays-in-nanoliter-droplets-using-scaffolded-aptamers
#6
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/28206750/synthetic-riboswitches-from-plug-and-pray-towards-plug-and-play
#7
Maja Etzel, Mario Mörl
In synthetic biology, metabolic engineering as well as gene therapy there is a strong demand for orthogonal or externally controlled regulation of gene expression. Here, RNA-based regulatory devices represent a promising emerging alternative to proteins, allowing a fast and direct control of gene expression, as no synthesis of regulatory proteins is required. Besides programmable ribozyme elements controlling mRNA stability, regulatory RNA structures in untranslated regions are highly interesting for engineering approaches...
February 16, 2017: Biochemistry
https://www.readbyqxmd.com/read/28206680/an-ssdna-aptamer-against-mannose-capped-lipoarabinomannan-enhances-anti-tuberculosis-activity-of-macrophages-through-downregulation-of-lipid-sensing-nuclear-receptor-peroxisome-proliferator-activated-receptor-%C3%AE-expression
#8
Qin Pan, Jiamin Yan, Qi Liu, Chunhui Yuan, Xiao-Lian Zhang
Mannose-capped lipoarabinomannan (ManLAM) is an immunomodulatory epitope of Mycobacterium tuberculosis (Mtb). We previously generated an aptamer (ZXL1) that specifically binds to ManLAM from the virulent Mtb H37Rv strain and reported that ZXL1 functioned as an antagonist, inhibiting the ManLAM-induced immunosuppression of dendritic cells (DCs). In the present study, we found that ZXL1 inhibited Mtb entry into murine macrophages. ZXL1 enhanced IL-1β and IL-12 mRNA expression and cytokine production in ManLAM-treated macrophages but decreased IL-10 production...
February 16, 2017: Microbiology and Immunology
https://www.readbyqxmd.com/read/28194280/cell-selex-identifies-a-sticky-rna-aptamer-sequence
#9
Partha Ray, Rebekah R White
Cell-SELEX is performed to select for cell binding aptamers. We employed an additional selection pressure by using RNAse to remove surface-binding aptamers and select for cell-internalizing aptamers. A common RNA sequence was identified from independent cell-SELEX procedures against two different pancreatic cancer cell lines, indicating a strong selection pressure towards this sequence from the large pool of other available sequences present in the aptamer library. The aptamer is not specific for the pancreatic cancer cell lines, and a similar sequence motif is present in previously published internalizing aptamers...
2017: Journal of Nucleic Acids
https://www.readbyqxmd.com/read/28193211/display-of-single-chain-variable-fragments-on-bacteriophage-ms2-virus-like-particles
#10
Christopher A Lino, Jerri C Caldeira, David S Peabody
BACKGROUND: Virus-like particles (VLPs) of the RNA bacteriophage MS2 have many potential applications in biotechnology. MS2 VLPs provide a platform for peptide display and affinity selection (i.e. biopanning). They are also under investigation as vehicles for targeted drug delivery, using display of receptor-specific peptides or nucleic acid aptamers to direct their binding to specific cell-surface receptors. However, there are few molecules more suited to the precise targeting and binding of a cellular receptor than antibodies...
February 13, 2017: Journal of Nanobiotechnology
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
#11
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
#12
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/28191852/artificial-chemical-reporter-targeting-strategy-using-bioorthogonal-click-reaction-for-improving-active-targeting-efficiency-of-tumor
#13
Hong Yeol Yoon, Min Lee Shin, Man Kyu Shim, Sangmin Lee, Jin Hee Na, Heebeom Koo, Hyukjin Lee, Jong-Ho Kim, Kuen Yong Lee, Kwangmeyung Kim, Ick Chan Kwon
Biological ligands such as aptamer, antibody, glucose and peptide have been widely used to bind specific surface molecules or receptors in tumor cells or subcellular structures to improve tumor-targeting efficiency of nanoparticles. However, this active targeting strategy has limitations for tumor targeting due to inter- and intra-heterogeneity of tumors. In this study, we demonstrated an alternative active targeting strategy using metabolic engineering and bioorthogonal click reaction to improve tumor-targeting efficiency of nanoparticles...
February 13, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28191845/self-assembled-nanoconstructs-modified-with-amplified-aptamers-inhibited-tumor-growth-and-retinal-vascular-hyperpermeability-via-vegf-capturing
#14
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
#15
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
#16
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
https://www.readbyqxmd.com/read/28187297/a-universal-aptameric-biosensor-multiplexed-detection-of-small-analytes-via-aggregated-perylene-based-broad-spectrum-quencher
#17
Rong Hu, Xi Zhang, Qiang Xu, Dan-Qing Lu, Yun-Hui Yang, Quan-Qing Xu, Qiong Ruan, Liu-Ting Mo, Xiao-Bing Zhang
A universal aptameric system based on the taking advantage of double-stranded DNA/perylene diimide (dsDNA/PDI) as the signal probe was developed for multiplexed detection of small molecules. Aptamers are single-stranded DNA or RNA oligonucleotides which are selected in vitro by a process known as systematic evolution of ligands by exponential enrichment. In this work, we synthesized a new kind of PDI and reported this aggregated PDI could quench the double-stranded DNA (dsDNA)-labeled fluorophores with a high quenching efficiency...
January 24, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28185322/a-difunctional-regeneration-scaffold-for-knee-repair-based-on-aptamer-directed-cell-recruitment
#18
Xiaoxia Hu, Yulan Wang, Yaning Tan, Jie Wang, Haoyang Liu, Yingqian Wang, Shuang Yang, Miusi Shi, Shiyong Zhao, Yufeng Zhang, Quan Yuan
To solve the challenge of poor knee repair, an aptamer-bilayer scaffold is designed for autologous mesenchymal stem cell (MSC) recruitment and osteochondral regeneration. The scaffold can efficiently recruit MSCs to the defect and induce the directional differentiation of MSCs, thus successfully achieving simultaneous regeneration of cartilage and bone in the knee joint.
February 10, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28183663/using-gold-nanostars-modified-pencil-graphite-electrode-as-a-novel-substrate-for-design-a-sensitive-and-selective-dopamine-aptasensor
#19
Rasoul Pourtaghavi Talemi, Seyed Mehdi Mousavi, Hossein Afruzi
For the first time, gold nanostars (GNS) were applied for electrostatic and covalent immobilizing a thiol modified Dopamine aptamer on the pencil graphite electrode and signal amplification. Dopamine aptamer was immobilized on the gold nanostars through electrostatic interaction between negatively charged phosphate groups of aptamer and positively charged gold nanostars and AuS well known covalent interaction. In the presence of Dopamine in the test solution, the charge transfer resistance (RCT) on the electrode surface increased with the increase of the Dopamine concentration due to specific interaction between Dopamine aptamer and Dopamine molecules, which made a barrier for electrons and inhibited the electron-transfer...
April 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28182974/diamond-based-electrochemical-aptasensor-realizing-a-femtomolar-detection-limit-of-bisphenol-a
#20
Yibo Ma, Junsong Liu, Hongdong Li
In this study, we designed and fabricated an electrochemical impedance aptasensor based on Au nanoparticles (Au-NPs) coated boron-doped diamond (BDD) modified with aptamers, and 6-mercapto-1-hexanol (MCH) for the detection of bisphenol A (BPA). The constructed BPA aptasensor exhibits good linearity from 1.0×10(-14) to 1.0×10(-9)molL(-1). The detection limitation of 7.2×10(-15)molL(-1) was achieved, which can be attributed to the synergistic effect of combining BDD with Au-NPs, aptamers, and MCH. The examine results of BPA traces in Tris-HCl buffer and in milk, UV spectra of aptamer/BPA and interference test revealed that the novel aptasensors are of high sensitivity, specificity, stability and repeatability, which could be promising in practical applications...
January 21, 2017: Biosensors & Bioelectronics
keyword
keyword
32408
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"