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Aptamers

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https://www.readbyqxmd.com/read/28326608/dnazyme-aptamer-or-aptamer-dnazyme-paradigm-biochemical-approach-for-aflatoxin-analysis
#1
Marzieh Jafari, Mohsen Rezaei, Heibatullah Kalantari, Maryam Tabarzad, Bahram Daraei
DNAzyme and aptamer conjugations have already been used for sensitive and accurate detection of several molecules. In this study, we tested the relationship between conjugation orientation of DNAzyme and Aflatoxin B1 aptamer and their subsequent peroxidase activity. Circular dichroism (CD) spectroscopy and biochemical analysis were used here to difference between these two conjugation patterns. Results showed that DNAzyme-aptamer has more catalytic activity and efficiency than aptamer-DNAzyme. Thereby, DNAzyme-aptamer with its superior efficiency can be used for design and development of more sensitive Aflatoxin B1 DNA based biosensors...
March 22, 2017: Biotechnology and Applied Biochemistry
https://www.readbyqxmd.com/read/28325909/nmr-monitoring-of-the-selex-process-to-confirm-enrichment-of-structured-rna
#2
Ryo Amano, Kazuteru Aoki, Shin Miyakawa, Yoshikazu Nakamura, Tomoko Kozu, Gota Kawai, Taiichi Sakamoto
RNA aptamers are RNA molecules that bind to a target molecule with high affinity and specificity using uniquely-folded tertiary structures. RNA aptamers are selected from an RNA pool typically comprising up to 10(15) different sequences generated by iterative steps of selection and amplification known as Systematic Evolution of Ligands by EXponential enrichment (SELEX). Over several rounds of SELEX, the diversity of the RNA pool decreases and the aptamers are enriched. Hence, monitoring of the enrichment of these RNA pools is critical for the successful selection of aptamers, and several methods for monitoring them have been developed...
March 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28325839/identification-and-characterization-of-rna-aptamers-a-long-aptamer-blocks-the-ampa-receptor-and-a-short-aptamer-blocks-both-ampa-and-kainate-receptors
#3
William J Jaremko, Zhen Huang, Wei Wen, Andrew Wu, Nicholas Karl, Li Niu
AMPA and kainate receptors, along with NMDA receptors, represent different subtypes of glutamate ion channels. AMPA and kainate receptors share a high degree of sequence and structural similarities, and excessive activity of these receptors has been implicated in neurological diseases such as epilepsy. Therefore, blocking detrimental activity of both receptor types could be therapeutically beneficial. Here, we report the use of an in vitro evolution approach involving systematic evolution of ligands by exponential enrichment with a single AMPA receptor target (i...
March 21, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28325302/aptamer-drug-conjugates-of-active-metabolites-of-nucleoside-analogs-and-cytotoxic-agents-inhibit-pancreatic-tumor-cell-growth
#4
Sorah Yoon, Kai-Wen Huang, Vikash Reebye, Duncan Spalding, Teresa M Przytycka, Yijie Wang, Piotr Swiderski, Lin Li, Brian Armstrong, Isabella Reccia, Dimitris Zacharoulis, Konstantinos Dimas, Tomokazu Kusano, John Shively, Nagy Habib, John J Rossi
Aptamer-drug conjugates (ApDCs) have the potential to improve the therapeutic index of traditional chemotherapeutic agents due to their ability to deliver cytotoxic drugs specifically to cancer cells while sparing normal cells. This study reports on the conjugation of cytotoxic drugs to an aptamer previously described by our group, the pancreatic cancer RNA aptamer P19. To this end, P19 was incorporated with gemcitabine and 5-fluorouracil (5-FU), or conjugated to monomethyl auristatin E (MMAE) and derivative of maytansine 1 (DM1)...
March 17, 2017: Molecular Therapy. Nucleic Acids
https://www.readbyqxmd.com/read/28325295/aptamers-for-cd-antigens-from-cell-profiling-to-activity-modulation
#5
REVIEW
Amin Nozari, Maxim V Berezovski
Nucleic acid-based aptamers are considered to be a promising alternative to antibodies because of their strong and specific binding to diverse targets, fast and inexpensive chemical synthesis, and easy labeling with a fluorescent dye or therapeutic agent. Cluster of differentiation (CD) proteins are among the most popular antigens for aptamers on the cell surface. These anti-CD aptamers could be used in cell biology and biomedicine, from simple cell phenotyping by flow cytometry or fluorescent microscopy to diagnosis and treatment of HIV/AIDS to cancer and immune therapies...
March 17, 2017: Molecular Therapy. Nucleic Acids
https://www.readbyqxmd.com/read/28325282/dna-aptamers-for-the-characterization-of-histological-structure-of-lung-adenocarcinoma
#6
Galina S Zamay, Tatiana I Ivanchenko, Tatiana N Zamay, Valentina L Grigorieva, Yury E Glazyrin, Olga S Kolovskaya, Irina V Garanzha, Andrey A Barinov, Alexey V Krat, Gleb G Mironov, Ana Gargaun, Dmitry V Veprintsev, Sergey S Bekuzarov, Andrey K Kirichenko, Ruslan A Zukov, Marina M Petrova, Andrey A Modestov, Maxim V Berezovski, Anna S Zamay
Nucleic acid aptamers are becoming popular as molecular probes for identification and imaging pathology and, at the same time, as a convenient platform for targeted therapy. Recent studies have shown that aptamers may be effectively used for tumor characterization and as commercially available monoclonal antibodies. Here we present three DNA aptamers binding to whole transformed lung cancer tissues, including tumor cells, connective tissues, and blood vessels. Protein targets have been revealed using affinity purification followed by mass spectrometry analyses, and they have been validated using a panel of correspondent antibodies and 3D imaging of tumor tissues...
March 17, 2017: Molecular Therapy. Nucleic Acids
https://www.readbyqxmd.com/read/28323404/electrophoretic-approach-for-the-simultaneous-deposition-and-functionalization-of-reduced-graphene-oxide-nanosheets-with-diazonium-compounds-application-for-sensing-in-serum
#7
Qian Wang, Alina Mihaela Vasilescu, Qi Wang, Yannick Coffinier, Musen Li, Rabah Boukherroub, Sabine Szunerits
Electrophoretic deposition (EPD) of reduced graphene oxide nanosheets (rGO) offers several advantages over other surface coating approaches, including process simplicity, uniformity of the deposited films and good control of the film thickness. The EPD conditions might also be of interest for the reduction of diazonium salts, which upon the release of N2 molecules and generation of radicals, can form covalent bonds with the sp2 hybridized carbon lattice atoms of rGO films. In this work, we report on the coating of gold electrodes in one-step with rGO/polyethyleneimine (PEI) thin films and their simultaneous modification using different phenyl (Ph) diazonium salt precursors bearing various functionalities such as -B(OH)2, -COOH and -C≡CH...
March 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28321500/aptahistochemistry-in-diagnostic-pathology-technical-scrutiny-and-feasibility
#8
REVIEW
Bakhtiar A Bukari, Marimuthu Citartan, Ewe Seng Ch'ng, Mawethu P Bilibana, Timofey Rozhdestvensky, Thean-Hock Tang
Antibodies have been the workhorse for diagnostic immunohistochemistry to specifically interrogate the expression of certain protein to aid in histopathological diagnosis. This review introduces another dimension of histochemistry that employs aptamers as the core tool, the so-called aptahistochemistry. Aptamers are an emerging class of molecular recognition elements that could recapitulate the roles of antibodies. The many advantageous properties of aptamers suited for this diagnostic platform are scrutinized...
March 20, 2017: Histochemistry and Cell Biology
https://www.readbyqxmd.com/read/28319905/a-new-amplified-%C3%AF-shape-electrochemical-aptasensor-for-ultrasensitive-detection-of-aflatoxin-b1
#9
Khalil Abnous, Noor Mohammad Danesh, Mona Alibolandi, Mohammad Ramezani, Ahmad Sarreshtehdar Emrani, Reza Zolfaghari, Seyed Mohammad Taghdisi
There is a prompt need for determination of aflatoxin B1 (AFB1) in food products to avoid distribution and consumption of contaminated food products. In this study, an accurate electrochemical sensing strategy was presented for detection of AFB1 based on aptamer (Apt)-complementary strands of aptamer (CSs) complex which forms a π-shape structure on the surface of electrode and exonuclease I (Exo I). The presence of π-shape structure as a double-layer physical barrier allowed detection of AFB1 with high sensitivity...
March 17, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28319903/fe-iii-based-metal-organic-framework-derived-core-shell-nanostructure-sensitive-electrochemical-platform-for-high-trace-determination-of-heavy-metal-ions
#10
Zhihong Zhang, Hongfei Ji, Yingpan Song, Shuai Zhang, Minghua Wang, Changchang Jia, Jia-Yue Tian, Linghao He, Xiaojing Zhang, Chun-Sen Liu
A new core-shell nanostructured composite composed of Fe(III)-based metal-organic framework (Fe-MOF) and mesoporous Fe3O4@C nanocapsules (denoted as Fe-MOF@mFe3O4@mC) was synthesized and developed as a platform for determining trace heavy metal ions in aqueous solution. Herein, the mFe3O4@mC nanocapsules were prepared by calcining the hollow Fe3O4@C that was obtained using the SiO2 nanoparticles as the template, followed by composing the Fe-MOF. The Fe-MOF@mFe3O4@mC nanocomposite demonstrated excellent electrochemical activity, water stability and high specific surface area, consequently resulting in the strong biobinding with heavy-metal-ion-targeted aptamer strands...
March 7, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28319902/ultra-high-sensitivity-of-the-non-immunological-affinity-of-graphene-oxide-peptide-based-surface-plasmon-resonance-biosensors-to-detect-human-chorionic-gonadotropin
#11
Nan-Fu Chiu, Chia-Tzu Kuo, Ting-Li Lin, Chia-Chen Chang, Chen-Yu Chen
Specific peptide aptamers can be used in place of expensive antibody proteins, and they are gaining increasing importance as sensing probes due to their potential in the development of non-immunological assays with high sensitivity, affinity and specificity for human chorionic gonadotropin (hCG) protein. We combined graphene oxide (GO) sheets with a specific peptide aptamer to create a novel, simple and label-free tool to detect abnormalities at an early stage of pregnancy, a GO-peptide-based surface plasmon resonance (SPR) biosensor...
March 7, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28318091/insulin-responsive-glucagon-delivery-for-prevention-of-hypoglycemia
#12
Jicheng Yu, Yuqi Zhang, Wujin Sun, Anna R Kahkoska, Jinqiang Wang, John B Buse, Zhen Gu
Hypoglycemia, the state of abnormally low blood glucose level, is an acute complication of insulin and sulfonylurea therapy in diabetes management. Frequent insulin dosing and boluses during daily diabetes care leads to an increased risk of dangerously low glucose levels, which can cause behavioral and cognitive disturbance, seizure, coma, and even death. This study reports an insulin-responsive glucagon delivery method based on a microneedle (MN)-array patch for the prevention of hypoglycemia. The controlled release of glucagon is achieved in response to elevated insulin concentration by taking advantage of the specific interaction between insulin aptamer and target insulin...
March 20, 2017: Small
https://www.readbyqxmd.com/read/28315675/low-intensity-training-and-the-c5a-complement-antagonist-nox-d21-rescue-the-mdx-phenotype-through-modulation-of-inflammation
#13
Janek Hyzewicz, Jun Tanihata, Mutsuki Kuraoka, Yuko Nitahara-Kasahara, Teiva Beylier, Urs T Ruegg, Axel Vater, Shin'ichi Takeda
Inflammatory events occurring in dystrophic muscles contribute to the progression of Duchenne muscular dystrophy (DMD). Low-intensity training (LIT) attenuates the phenotype of mdx mice, an animal model for DMD. Therefore, we postulated that LIT could have anti-inflammatory properties. We assessed levels of inflammatory cytokines and infiltrated immune cells in gastrocnemius muscle of mdx mice after LIT. We detected high levels of complement component C5a, chemokine ligand (CCL) 2, CD68(+) monocytes/macrophages, and proinflammatory M1 macrophages in muscles of mdx mice...
March 15, 2017: American Journal of Pathology
https://www.readbyqxmd.com/read/28315316/label-free-and-rapid-detection-of-atp-based-on-structure-switching-of-aptamers
#14
Danyang Ji, Hongqi Wang, Jia Ge, Lin Zhang, Jianjun Li, Dongmei Bai, Juan Chen, Zhaohui Li
In this work, an aptamer-based fluorescent strategy for label-free detection of ATP was developed by using Thioflavin T (ThT) as a fluorescence indicator, which can specifically bind with G-quadruplex DNAs to generate enhanced fluorescence intensity. In the absence of ATP, the folded structure of ATP aptamer allows the intercalation of ThT to produce strong fluorescence signal. However, upon ATP binding to the aptamer where ThT intercalated, the conformational change or distortion of the aptamer is large enough to cause much less intercalation of ThT and consequently drastic suppression of the fluorescence intensity...
March 14, 2017: Analytical Biochemistry
https://www.readbyqxmd.com/read/28301944/orientation-and-characterization-of-immobilized-antibodies-for-improved-immunoassays-review
#15
Nicholas G Welch, Judith A Scoble, Benjamin W Muir, Paul J Pigram
Orientation of surface immobilized capture proteins, such as antibodies, plays a critical role in the performance of immunoassays. The sensitivity of immunodiagnostic procedures is dependent on presentation of the antibody, with optimum performance requiring the antigen binding sites be directed toward the solution phase. This review describes the most recent methods for oriented antibody immobilization and the characterization techniques employed for investigation of the antibody state. The introduction describes the importance of oriented antibodies for maximizing biosensor capabilities...
March 16, 2017: Biointerphases
https://www.readbyqxmd.com/read/28301410/allergic-reaction-upon-intravitreal-administration-of-anti-vascular-endothelial-growth-factor-agents
#16
Gavin G Meredith, Paul A Schkade, Brian C Joondeph
PURPOSE: To describe the patient's allergic response to anti-vascular endothelial growth factor drugs after receiving intravitreal bevacizumab for choroidal neovascularization. METHODS: Clinical case report. RESULTS: Formal allergy evaluation revealed hypersensitivity to bevacizumab and ranibizumab, but not to pegaptanib or aflibercept. CONCLUSION: Bevacizumab and ranibizumab are derivatives of murine monoclonal antibodies, whereas pegaptanib is an aptamer and aflibercept is a fusion protein of human origin...
March 15, 2017: Retinal Cases & Brief Reports
https://www.readbyqxmd.com/read/28300769/aptamers-biomedical-interest-and-applications
#17
EDITORIAL
Cristina Romero-López, Alfredo Berzal-Herranz
Aptamers are short DNA or RNA oligonucleotides specialized in the specific and efficient binding to a target molecule. They are obtained by in vitro selection or evolution processes. It was in 1990 that two independent research groups described the bases of a new in vitro technology for the identification of RNA molecules able to specifically bind to a target [1,2]. Tuerk and Gold established the principals of the in vitro selection process that was named SELEX (Systematic Evolution of Ligands by Exponential enrichment), which is based on iterative cycles of binding, partitioning, and amplification of oligonucleotides from a pool of variant sequences [2]...
March 16, 2017: Pharmaceuticals
https://www.readbyqxmd.com/read/28300246/pore-modulation-of-zirconium-organic-frameworks-for-high-efficiency-detection-of-trace-proteins
#18
Chun-Sen Liu, Zhi-Hong Zhang, Min Chen, Hui Zhao, Feng-He Duan, Di-Ming Chen, Ming-Hua Wang, Shuai Zhang, Miao Du
Tunable electrochemical biosensors based on analogous Zr-MOFs were developed for protein detection, the performances of which rely on the pore sizes and surroundings of the MOFs that show diverse binding behaviors to aptamers and then the targeted proteins. The optimized Zr-MOF-based sensor has high selectivity to lysozyme in a wide concentration range and a low detection limit of 3.6 pg mL(-1), with good repeatability, stability, and applicability in real samples. This work will establish a new platform for biosensing and extend the application scope of MOF materials...
March 16, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28299702/optical-and-electrochemical-aptasensors-for-sensitive-detection-of-streptomycin-in-blood-serum-and-milk
#19
Mohammad Ramezani, Khalil Abnous, Seyed Mohammad Taghdisi
Detection and quantitation of antibiotic residues in blood serum and foodstuffs are in great demand. We have developed aptasensors for detection of streptomycin using electrochemical and optical methods. In the first method, an electrochemical aptasensor was developed for sensitive and selective detection of streptomycin, based on combination of exonuclease I (Exo I), complementary strand of aptamer (CS), arch shaped structure of aptamer (Apt)-CS conjugate, and gold electrode. The designed electrochemical aptasensor exhibited high selectivity toward streptomycin with a limit of detection (LOD) as low as 11...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28299701/aptasensors-for-detection-of-avian-influenza-virus-h5n1
#20
Yanbin Li, Ronghui Wang
Aptamers are single-stranded RNA or DNA oligonucleotides which have specific three-dimensional (3D) structures for high affinity and specific recognition to their target. In diagnostic and detection assays, aptamers represent an alternative to antibodies as recognition agents and offer advantages, such as reduced cost, rapid and reproducible synthesis, controllable modification, and improved stability. Aptamers are favorably used in biosensors as sensitive and selective bio-receptors coupled with a variety of transducers such as optical, mass-sensitive, and electrochemical sensors, the so-called aptasensors...
2017: Methods in Molecular Biology
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