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Dna aptamer

Katherine D Hills, Daniela A Oliveira, Nicholas D Cavallaro, Carmen L Gomes, Eric S McLamore
We demonstrate a sensing mechanism for rapid detection of Listeria monocytogenes in food samples using the actuation of chitosan-aptamer nanobrush borders. The bio-inspired soft material and sensing strategy mimic natural symbiotic systems, where low levels of bacteria are selectively captured from complex matrices. To engineer this biomimetic system, we first develop reduced graphene oxide/nanoplatinum (rGO-nPt) electrodes, and characterize the fundamental electrochemical behavior in the presence and absence of chitosan nanobrushes during actuation (pH-stimulated osmotic swelling)...
March 15, 2018: Analyst
Akram Norouzi, Hadi Ravan, Abbas Mohammadi, Elyas Hosseinzadeh, Mahdieh Norouzi, Tahereh Fozooni
The development of powerful techniques to detect cancer cells at early stages plays a notable role in diagnosing and prognosing cancer patients and reducing mortality. This paper reports on a novel functional DNA nanoassembly capable of detecting cancer cells based on structural DNA nanotechnology. DNA nanoassemblies were constructed by the self-assembly of a DNA concatemer to a plenty of sticky-ended three-way junctions. While an aptamer moiety guided the nanoassembly to the target cancer cell, the peroxidase-mimicking DNAzymes embedded in the nanoassemblies were used as the sensing element to produce colorimetric signals...
August 9, 2018: Analytica Chimica Acta
Li Wang, Aiguo Wu, Gang Wei
Graphene-based nanomaterials have been widely utilized to fabricate various biosensors for environmental monitoring, food safety, and biomedical diagnostics. The combination of aptamers with graphene for creating biofunctional nanocomposites improved the sensitivity and selectivity of fabricated biosensors due to the unique molecular recognition and biocompatibility of aptamers. In this review, we highlight recent advances in the design, fabrication, and biomedical sensing application of graphene-based aptasensors within the last five years (2013-current)...
March 12, 2018: Analyst
Jinan Tuma Sabah, Razauden Mohamed Zulkifli, Shafinaz Shahir, Farediah Ahmed, Mohammed Rafiq Abdul Kadir, Zarita Zakaria
Distinctive bioactivities possessed by luteolin (3', 4', 5, 7-tetrahydroxy-flavone) are advantageous for sundry practical applications. This paper reports the in vitro selection and characterization of single stranded-DNA (ssDNA) aptamers, specific for luteolin (LUT). 76-mer library containing 1015 randomized ssDNA were screened via systematic evolution of ligands by exponential enrichment (SELEX). The recovered ssDNA pool from the 8th round was amplified with unlabeled primers and cloned into PSTBlue-1 vector prior to sequencing...
March 6, 2018: Analytical Biochemistry
Sai Wang, Yiyang Dong, Xingguo Liang
Although surface plasmon resonance (SPR) technique and aptamer technology shows great potential in analytical and biological chemistry, direct capture and analysis of small molecules using SPR remains tough. Detection sensitivity of aptasensor and recognition ability of aptamer is limited, because direct immobilization of aptamer causes large steric hindrance and strand entanglement. Herein, we chose a typical small molecule-tetracycline (Mw. 444.4 g/mol) as a model, and combined aptamer technology, DNA nanostructure, and commercial Biacore T200 SPR instrument to develop a straightforward format SPR aptasensor...
February 27, 2018: Biosensors & Bioelectronics
Hong Liang, Shan Chen, Peipei Li, Liping Wang, Jingying Li, Juan Li, Huang-Hao Yang, Weihong Tan
Herein, we report a nongenetic and real-time approach for imaging protein dimerization on living cell surfaces by aptamer recognition and proximity-induced DNA assembly. We use the aptamer specific for the receptor monomer as a recognition probe. When receptor dimerization occurs, the dimeric receptors bring two aptamer probes into close proximity, thereby triggering dynamic DNA assembly. The proposed approach was successfully applied to visualize dimerization of Met receptor and transforming growth factor-β type II receptor...
March 9, 2018: Journal of the American Chemical Society
Wesley O Tucker, Andrew B Kinghorn, Lewis A Fraser, Yee-Wai Cheung, Julian A Tanner
Nucleic acid aptamers hold promise as therapeutic tools for specific, tailored inhibition of protein targets with several advantages when compared to small molecules or antibodies. Nuclear WW domain containing E3 ubiquitin ligase 1 (WWP1) ubiquitin ligase poly-ubiquitinates Runt-related transcription factor 2 (Runx2), a key transcription factor associated with osteoblast differentiation. Since WWP1 and an adapter known as Schnurri-3 are negative regulators of osteoblast function, the disruption of this complex has the potential to increase bone deposition for osteoporosis therapy...
March 7, 2018: International Journal of Molecular Sciences
Chen Zhou, Haimin Zou, Chengjun Sun, Dongxia Ren, Wei Xiong, Yongxin Li
Based on a novel signal amplification strategy by catalytic hairpin assembly and displacement of G-quadruplex DNA, an enzyme-free, non-label fluorescent aptasensing approach was established for sensitive detection of four tetracycline veterinary drugs in milk. The network consisted of a pair of partially complementary DNA hairpins (HP1 and HP2). The DNA aptamer of four tetracycline veterinary drugs was located at the sticky end of the HP1. The ring region of HP1 rich in G and C could form a stable G-quadruplex structure, which could emit specific fluorescence signal after binding with the fluorescent dye and N-methylmesoporphyrin IX (NMM)...
March 8, 2018: Analytical and Bioanalytical Chemistry
Yanli Ma, Yu Mao, Yuan An, Tian Tian, Huimin Zhang, Jinmao Yan, Zhi Zhu, Chaoyong James Yang
We have successfully developed a target-responsive aptamer cross-linked hydrogel for the visual detection of glucose, an important biomedical analyte. In this work, the glucose-responsive hydrogel was prepared using the target aptamer and its two short complementary DNA strands grafted onto a linear polyacrylamide chain as cross-linkers. Gold nanoparticles (AuNPs) modified with thiol-PEG were encapsulated in the gel and used as the output signal for visible detection. The complex of glucose and its ligand of boronic acid derivatives (Shinkai's receptor) can bind with the aptamer to disrupt the hydrogel, leading to the release of AuNPs with a distinct red colour in the supernatant...
March 7, 2018: Analyst
Huilei Dong, Hongfei Chen, Juqian Jiang, Hui Zhang, Chenxin Cai, Qingming Shen
Sensitive and specific detection of tumor exosomes is of great significance for early cancer diagnosis. In this paper, we report an aptamer strategy for exosome detection based on aptamer recognition-induced multi-DNA release and cyclic enzymatic amplification. First, we use aptamer-magnetic bead bioconjugates to capture tumor exosomes derived from LNCaP cells, leading to the release of three kinds of messenger DNAs (mDNAs). After magnetic separation, the released mDNAs hybridized with the probe DNAs immobilized on a gold electrode...
March 7, 2018: Analytical Chemistry
Wenjuan Chen, Yuan Chen, Meilan Wang, Yuwu Chi
Ultrasensitive chemiluminescence (CL) sensors for biomolecules (DNA and proteins) have been developed by adopting DNA-functionalized silver-cysteine hybrid nanowires (p-SCNWs) as signal amplifying labels. The sensing is established from a sandwich-type DNA hybridization, where the target DNA strands are initially hybridized with the capture DNA located at paramagnetic microspheres (PMs) and subsequently hybridized with p-SCNWs functionalized with the signal DNA probe. After magnetic separation, p-SCNWs on the hybrids were completely decomposed with HNO3 to release numerous silver ions...
March 6, 2018: Analyst
Michael Gotrik, Gurpreet Sekhon, Saumya Saurabh, Margaret Nakamoto, Michael Eisenstein, H Tom Soh
RNA aptamers that generate a strong fluorescence signal upon binding a nonfluorescent small-molecule dye offer a powerful means for the selective imaging of individual RNA species. Unfortunately, conventional in vitro discovery methods are not efficient at generating such fluorescence-enhancing aptamers, because they primarily exert selective pressure based on target affinity-a characteristic that correlates poorly with fluorescence enhancement. Thus, only a handful of fluorescence-enhancing aptamers have been reported to date...
March 5, 2018: Journal of the American Chemical Society
Christy Hui, Meng Liu, Yingfu Li, John David Brennan
We report a paper-based aptasensor platform that uses two reaction zones and a connecting bridge along with printed multifunctional bio/nano materials to achieve molecular recognition and signal amplification. Upon addition of analyte to the first zone, a fluorescently labelled DNA or RNA aptamer is desorbed from printed graphene oxide, rapidly producing an initial fluorescence signal. The released aptamer then flows to the second zone where it reacts with printed reagents to initiate rolling circle amplification, generating DNA amplicons containing a peroxidase-mimicking DNAzyme, which produces a colorimetric readout that can be read in an equipment-free manner or with a smartphone...
March 5, 2018: Angewandte Chemie
Haibiao Xie, Hengji Zhan, Qunjun Gao, Jianfa Li, Qun Zhou, Zhicong Chen, Yuhan Liu, Mengting Ding, Huizhong Xiao, Yuchen Liu, Weiren Huang, Zhiming Cai
Both oncogenic transcription factors (TFs) and microRNAs (miRNAs) play important roles in human cancers, acting as transcriptional and post-transcriptional regulators, respectively. These phenomena raise questions about the ability of an artificial device to simultaneously regulate miRNAs and TFs. In this study, we aimed to construct artificial long non-coding RNAs, "alncRNAs", and to investigate their therapeutic effects on bladder cancer cell lines. Based on engineering principles of synthetic biology, we combined tandem arrayed aptamer cDNA sequences for TFs with tandem arrayed cDNA copies of binding sites for the miRNAs to construct alncRNAs...
March 1, 2018: Cancer Letters
Rui Yang, Shuwen Liu, Zhenjie Wu, Ying Tan, Shuqing Sun
In this work, we developed a robust and ultrasensitive bio-sensor based on the target-aptamer recognition strategy and microscopic enumeration of gold nanoparticles (AuNPs) using dark field microscopy (DFM). The aptasensor with a core-shell structure consisting of a magnetic bead (MB), aptamer and AuNPs was fabricated by complementary hybridization of the DNA probe on the AuNPs surface to the aptamer coupled to the MB. Upon addition of the target molecule, the strong interaction between the aptamer and the target molecule, thrombin, results in the release of the AuNPs from the MB...
May 15, 2018: Talanta
Atefeh Sarafan Sadeghi, Mohammad Mohsenzadeh, Khalil Abnous, Seyed Mohammad Taghdisi, Mohammad Ramezani
Specific ssDNA aptamers for the antibiotic florfenicol (FF) were developed from an enriched nucleotide library using magnetic beads-based SELEX (Systematic Evolution of Ligands by EXponential enrichment) technique with high-binding affinity. After 12 rounds of selection, thirty-six sequences were obtained that were then divided into five major families, according to the primary sequence similarity. Binding affinity analyses of three fluorescently tagged aptamers belonging to different families demonstrated that the dissociation constants (Kd ) were in the low nanomolar range (Kd = 52...
May 15, 2018: Talanta
Baozhu Zhang, Chunying Wei
A novel turn-on fluorescent biosensor has been constructed using C-PS2.M-DNA-templated silver nanoclusters (Ag NCs) with an average diameter of about 1 nm. The proposed approach presents a low-toxic, simple, sensitive, and selective detection for Pb2+ . The fluorescence intensity of C-PS2.M-DNA-Ag NCs enhances significantly in the presence of Pb2+ , which is attributed to the special interaction between Pb2+ and its aptamer DNA PS2.M. Pb2+ induces the aptamer to form G-quadruplex and makes two darkish DNA/Ag NCs located at the 3' and 5' terminus close, resulting in the fluorescence light-up...
May 15, 2018: Talanta
Xingmei Zhang, Li Peng, Zhiman Liang, Zhewen Kou, Yue Chen, Guangwei Shi, Xiaowen Li, Yanling Liang, Fang Wang, Yusheng Shi
Glioblastoma multiforme (GBM) is the most prevalent and lethal malignant intracranial tumor in the brain, with very poor prognosis and survival. The epidermal growth factor receptor variant III (EGFRvIII) contributes to increased oncogenicity that does not occur through binding EGFR ligands and instead occurs through constitutive activation, which enhances glioma tumorigenicity and resistance to targeted therapy. Aptamers are nucleic acids with high affinity and specificity to targets selected by systematic evolution of ligands by exponential enrichment (SELEX), and are usually developed as antagonists of disease-associated factors...
March 2, 2018: Molecular Therapy. Nucleic Acids
Weronika Kotkowiak, Jolanta Lisowiec-Wachnicka, Jakub Grynda, Ryszard Kierzek, Jesper Wengel, Anna Pasternak
Thrombin is a serine protease that plays a crucial role in hemostasis, fibrinolysis, cell proliferation, and migration. Thrombin binding aptamer (TBA) is able to inhibit the activity of thrombin molecule via binding to its exosite I. This 15-nt DNA oligonucleotide forms an intramolecular, antiparallel G-quadruplex structure with a chair-like conformation. In this paper, we report on our investigations on the influence of certain modified nucleotide residues on thermodynamic stability, folding topology, and biological properties of TBA variants...
March 2, 2018: Molecular Therapy. Nucleic Acids
Hamid Sedighian, Raheleh Halabian, Jafar Amani, Mohammad Heiat, Ramezan Ali Taheri, Abbas Ali Imani Fooladi
Staphylococcal enterotoxin A (SEA) is an enterotoxin produced mainly by Staphylococcus aureus. In recent years, it has become the most prevalent compound for staphylococcal food poisoning (SFP) around the world. In this study, we isolate new dual-function single-stranded DNA (ssDNA) aptamers by using some new methods, such as the Taguchi method, by focusing on the detection and neutralization of SEA enterotoxin in food and clinical samples. For the asymmetric polymerase chain reaction (PCR) optimization of each round of systematic evolution of ligands by exponential enrichment (SELEX), we use Taguchi L9 orthogonal arrays, and the aptamer mobility shift assay (AMSA) is used for initial evaluation of the protein-DNA interactions on the last SELEX round...
February 26, 2018: Analytical Biochemistry
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