Thank you for considering to present your work as a poster at Aptamers 2019.
Please prepare your poster in A1 portrait format (59cm wide x 84cm long). Please do not laminate your poster or use heavy printing material. Further information about poster sizes can be found on the following link:
Posters larger than A1 will only be displayed subject to the availability of space.
Maximum capacity 30 A1 posters
Please ensure you have appropriate permissions for the publication of your abstract from the original copyright holders. Should you wish your abstract not to be published, please notify us in writing at the time of abstract submission.
Invitation to submit an article to the journal AptamersWe invite you to submit your research to the journal Aptamers (ISSN: 2514-3247), which is a new official open-access journal of the International Society on Aptamers, dedicated to publishing peer-reviewed research and reviews on all aspects of aptamer research.
We are happy to waive basic open access publication fee until 30 September 2019 for Aptamers 2019 delegates, as long as the manuscripts are prepared according to the guidelines for authors.
If your abstract has been accepted for presentation but it does not appear in the list below, please let us know as soon as possible by email on aptamersoxford@gmail.com.
(Presenter in bold)
Generation of Aptamers Using SELEX for Detection of Lucentis on Microfluidic Chip
Tanu Bhardwaj, Sandeep K Jha
Centre for Biomedical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi-110016.
In this work, we are reporting a low-cost disposable microfluidic chip with SELEX(Systematic evolution of ligands by exponential enrichment) generated aptamer as biorecognition molecule for inline monitoring of lucentis in fermentors. Lucentis is a therapeutic protein injected as a drug into eye of a patient to treat a disease called age related macular degeneration. Presently, the available techniques for detection of lucentis in fermentors are offline monitoring techniques like HPLC(High pressure liquid chromatography), protein-L assays and chromatography. Due to longer detection time and higher expense of HPLC, and non-specificity of protein-L methods, there is a huge demand of a low cost device for inline monitoring of lucentis specifically in fermentors. For this, we generated a specific aptamer for lucentis using SELEX. In SELEX, for binding step, we immobilised lucentis on sepharose beads as matrix in a glass column and performed affinity chromatography with random ssDNA sequences. Then, for elution, combination of various techniques like salting out, pH change and heat were applied to get a pool of specific aptamers for lucentis.
Development of Aptamer-Field-Effect Transistor Sensors: Towards Point of Care
Kevin M Cheung,1,2 Nako Nakatsuka,1,2 Kyung-Ae Yang,3 Chuanzhen Zhao,1,2 Hongyan Yang,5 Paul S Weiss,1,2 Milan N Stojanović,3,4 and Anne M Andrews1,2,5
1California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California, United States
2Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, United States
3Division of Experimental Therapeutics, Department of Medicine, Columbia University, New York, New York, United States
4Biomedical Engineering and Systems Biology, Columbia University, New York, New York, United States
5Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, and Hatos Center for Neuropharmacology, University of California, Los Angeles, Los Angeles, California, United States
We have designed and developed ultrathin-film field-effect transistors (FETs) coupled to rationally designed and chemically synthesized oligonucleotide sequences with molecular recognition capabilities, termed aptamers, for the detection of a diverse range of biologically important small-molecule targets (e.g., neurotransmitters, amino acids, sugars, lipids). Upon target capture, aptamers undergo conformational changes that redistribute charge densities on FET surfaces resulting in measurable changes in conductance. We demonstrate detection of targets in full ionic strength biological fluids, with high specificity and selectivity, over a dynamic range of concentrations with ultra-low detection limits. Using this platform, we are developing sensors for the direct detection of the amino acid phenylalanine for potential point-of-care use for patients with phenylketonuria (PKU), a common genetic disorder that results in elevated and potentially harmful levels of phenylalanine in the blood and brain. Three phenylalanine-specific DNA sequences were investigated to determine sensor responses contingent on different primary base sequences, secondary structures, and target affinities.
Aptamer-based Biomarker Assay for Cancer Detection
Nico Dreymann1, Julia Wünsche2, Anja Klevesath1, Denise Czepluch1, Wiebke Sabrowski1 and Marcus Menger1
1Fraunhofer Institute for Cell Therapy and Immunology, Branch Bioanalytics and Bioprocesses (IZI-BB), Functional Nucleic Acids – Aptamers, Am Mühlenberg 13, D-14476 Potsdam, Germany
23B Pharmaceuticals GmbH, Magnusstraße 11, D-12489 Berlin, Germany
Bladder cancer is one of the most frequently occurring tumour diseases worldwide with an estimated 30,000 new cases diagnosed each year, especially in men. The current diagnostic gold standard methods are cystoscopy and biopsy of the tumour tissue. Non-invasive alternatives such as urine cytology are also expensive methods and inadequate for early detection. Further, superficial tumours of the bladder wall have a high risk of relapse that necessitates regular monitoring by cystoscopy. Therefore, we work on the development of a non-invasive and less expensive alternative that is suitable for early detection of bladder cancer using DNA-aptamers. These highly specific recognition elements will be used for the detection of tumour-specific markers in urine samples.
A “Swiss Army Knife” Approach Using Aptamers and Nanopores
Rhushabh Maugi 1, Mark Platt 1
1 Department of Chemistry, Loughborough University. Leicester. UK LE11 3TU
Resistive pulse sensing (RPS) is an electrochemical nanopore sensing platform that characterises nanoparticles that range from sub 100nm to micrometer sized particles. A RPS nanopore sensor creates a “swiss army knife” multi-use platform to analyse ions, particles and biological targets in solution. Measuring the interaction between aptamers and small molecules, proteins, cells, virus etc. is well suited to a nanopore platform. The aptamer adopts a tertiary structure in the presence of the target and this results in a change in charge density around the particle which is measured as a change in translocation speed on the RPS platform.
ICOS costimulation with targeted agonist aptamer at the tumor site enhances CTLA-4 blockade therapy
Mario Martínez Soldevilla, Helena Villanueva, Fernando Pastor
Molecular Therapeutics Program, Center for Applied Medical Research, CIMA, University of Navarra, Pamplona, Spain
Inducible T-cell costimulator (ICOS) is a receptor induced on the surface of pre-activated CD4 and CD8 T lymphocytes, but also on Tregs, opening the debate whether ICOS costimulation could be pro-tumorigenic or anti-tumorigenic. In the last few years ICOS signaling has gained scope as a possible potential marker to predict response to CTLA-4 blockade therapy as well as to enhance its therapeutic effect. It has been reported that CTLA-4 antibody can deplete Tregs in the tumor leaving the action of ICOS costimulation only on effector T cells. There is no direct accessibility to ICOS agonist monoclonal antibodies leading us to develop alternative aptamer-based ICOS agonist molecules. Aptamers are single-stranded oligonucleotide ligands that can be engineered to act as multivalent “chemical antibodies.” Herein we describe that intratumoral injection of an ICOS agonist (IApt8) potentiates anti-CTLA-4 therapy in various tumor models. In vitro, experiments with IApt8 resulted in significant activation of CD4 and CD8 T cells measured by proliferation and IFN-γ production. In vivo, the combination of CTLA-4 blockade with IApt8 induced a 90% of tumor rejection in the murine Hepatocarcinoma model (Hepa 129).
Generation of DNA aptamers against small molecules using Capture-SELEX
Wiebke Sabrowski, Anja Klevesath, Denise Czepluch, Nico Dreymann and Marcus Menger
Fraunhofer Institute for Cell Therapy and Immunology, Branch Bioanalytics and Bioprocesses (IZI-BB), Functional Nucleic Acids – Aptamers, Am Mühlenberg 13, D 14476 Potsdam, Germany
Micropollution of aquatic systems is an environmental challenge of major concern. 17-ß-estradiol is an endocrine disrupting chemical frequently found in wastewater treatment plant effluents worldwide. The effects of exposure to 17-ß-estradiol have been extensively studied inter alia in fish and include impaired reproduction, changes in sex ratio and intersexuality. However, detection of 17-ß-estradiol is mostly limited to well-equipped facilities with well-trained personnel. Therefore, the development of on-site detection platforms is highly desirable. Aptamers are promising molecules for the development of biosensors. However, using conventional SELEX methods, the selection of aptamers against small molecules is challenging. Such targets are not likely to induce major changes in characteristics of the aptamer-target complex when compared to the aptamer alone, nor are they suitable for immobilization.
Analysis of Ligand-Induced Structure Switching in Cocaine-Binding Aptamer Using Fluorescence Kinetics of Stilbene Photoisomerization
Aron A Shoara1, Logan W Donaldson2, Philip E Johnson1
1Department of Chemistry and Centre for Research on Biomolecular Interactions, York University, Toronto, ON, M3J 1P3 Canada
2Department of Biology, York University, Toronto, ON, M3J 1P3 Canada
Fluorescent biosensors are in-demand techniques for their sensitivity, robustness and cost effectiveness. Conventional fluorescence sensing of aptamers depends on emission measurements by comparing signals in the presence and absence of analytes. However, conventional techniques do not provide information on whether an aptamer is undergoing a structure-switching binding mechanism. Photoisomerization reaction mechanisms are powerful means in the development of aptamer sensors, where the absorption or emission of light is converted to detectable electrical signals. We utilized the cis-trans photoisomerization of 4-acetamido-4′-isothiocyanato-2,2′-stilbenedisulfonic acid (SITS) conjugated with two constructs of cocaine-binding aptamer (MN19 and MN4).
Antimalarial Compounds: Cocaine-Binding Aptamer Specific or Generic DNA Binders
Sladjana Slavkovic and Philip E Johnson
Department of Chemistry, York University, Toronto, ON, M3J 1P3, Canada
Aptamers have generated great interest as biosensors as their selection process allows them to bind a wide variety of ligands, often with high affinity and specificity. An aptamer that is an exception is the cocaine-binding aptamer as one of the unique features of this aptamer is its ligand-binding promiscuity. Despite being selected for cocaine, the cocaine-binding aptamer binds quinine and quinine-based antimalarial compounds (amodiaquine, chloroquine and mefloquine) with much higher affinity than cocaine. A second unique feature of this aptamer is having a salt-controlled two-site binding mechanism. Our recent study shows that the cocaine-binding aptamer also binds two copies of artemisinin, a non-quinine based antimalarial compound, about 100-fold tighter than cocaine. We used isothermal titration calorimetry (ITC) to determine whether quinine, amodiaquine, chloroquine, mefloquine and artemisinin are specific to the cocaine binding aptamer or if they are generic DNA binders.
Characterization of the Ochratoxin-A-binding aptamer and binding to its ligand
Zachary R Churcher, Sladjana Slavkovic, Aron A Shoara, Philip E Johnson
NMR spectroscopy, isothermal titration calorimetry (ITC), and UV-Vis spectroscopy are being used to investigate the interaction between the ochratoxin-A-binding aptamer (OTA) and its ligand ochratoxin-A. Ochratoxin A is a mycotoxin produced by certain types of Penicillium and Apsergillus fungi. Found in grain, pork and a number of other sources, Ochratoxin-A is one of the most abundant food contaminating mycotoxins. Ochratoxin-A is a strong neurotoxin thought to deplete dopamine levels in brain and may be weakly mutagenic causing oxidative damage to DNA. The OTA aptamer is predicted to be a monomolecular antiparallel G-quadruplex with a two G-tetrad core, and two tails extending from the same face of the quadruplex.
