Aptamer Poster Gallery

Welcome to the Aptamer Gallery where aptamer research is published for consideration.  Our aim is to provide an open forum where the latest research and discoveries can be shared.  We know there is much stimulating research in this area and we would like to highlight your exciting innovations. To add content fill out the form here.



Rapid DNA Aptamer Binding Characterization and ELASA Development Using Biolayer Interferometry (BLI)Nucleic acid aptamers are high affinity, high selectivity ligands produced in vitro by a process commonly known as “SELEX”. Primarily due to the expiration of major intellectual property restricting their use, the aptamer class of affinity reagents is poised for considerable growth in a variety of diagnostic application areas [1,2]. Specifically, the ability to inexpensively synthesize a well-defined chemical reagent represents a major advantage of aptamers over antibodies. While the selection of DNA and RNA aptamers has been described for some time, the SELEX process was traditionally performed against a single target at a time requiring weeks to months for successful execution. We have developed a proprietary process for multiplexing SELEX to discover aptamers against multiple targets simultaneously, thereby greatly increasing the throughput of aptamer discovery. The increased productivity, however, requires us to address aptamer validation (i.e. Kd determination) in a high throughput fashion as well. In contrast to surface plasmon resonance, biolayer interferometry (BLI) has no flow cell or microfliuidic channels susceptible to clogging. BLI experiments on ForteBio’s Octet Red 96TM are performed in a standard 96 well plate. Additionally, sensors come with facile chemistries for target immobilization requiring little or no experiment-to-experiment optimization. Herein we describe the use of BLI instrumentation for rapid validation of putative aptamer sequences. Such aptamers are generally selected to bind protein or peptide targets of high diagnostic potential. Finally, taking these validations a step further, we describe the use of BLI for further screening of multiple aptamer clones for complementarity in an ELISA-like pairs of “sandwich” assays. Others have termed such aptamerbased ELISAs as “Enzyme Linked Aptamer Sorbent Assay” or “ELASA”. Because kinetics are inherently followed, the optimization of such assays by BLI allows a highly educated subsequent translation of the assay to conventional instrumentation such as fluorescent plate readers.

Demonstration and Optimization of Multiple Aptamer-ELISA “ELASA” Assays with Novel DNA AptamersWhile the ELISA method is generally very sensitive with specificity depending on the quality of primary detection antibody, protein-based antibody reagents are not very stable in non-refrigerated (i.e. point-of-care) applications. In contrast, DNA aptamers are extremely stable in both hydrated and lyophilized form and therefore amenable to field-deployed assays. Towards using such reagents, we are demonstrating their suitability in several modified ELISA formats termed enzyme-linked aptamer sorbent assays or “ELASA”. Using novel aptamers, here we demonstrate both direct and sandwich ELASA approaches. For each of the approaches we determine their apparent limit of detection.
Recombinant Antibodies and Aptamers are Viable Alternative to Animal-based Antibody Production MethodsThe precise specificity and strong affinity of binding that makes antibodies an irreplaceable component of adaptive immunity are the characteristics that are harnessed in molecular biology, clinical medicine, and multiple other scientific disciplines to identify and label proteins of interest.  Because antibody-based affinity reagents are so widely used and the historically-used production process is painful and distressing for the animals used, their replacement with completely non-animal derived technologies should be a priority. Fortunately, viable alternatives that can be incorporated into most protocols that require affinity reagents are available. Because these non-animal alternatives actually have several technical advantages over traditionally produced antibodies, we are working to make researchers aware of their options in order to facilitate wider use of these reagents and greater compliance with the spirit of federal animal welfare policies.
Darwinian evolution of an alternative genetic system provides support for TNA as an RNA progenitorThe pre-RNA world hypothesis postulates that RNA was preceded in the evolution of life by a simpler genetic material, but it is not known if such systems can fold into structures capable of eliciting a desired function. Presumably, whatever chemistry gave rise to RNA would have produced other RNA analogues, some of which may have preceded or competed directly with RNA. Threose nucleic acid (TNA), a potentially natural derivative of RNA, has received considerable interest as a possible RNA progenitor due to its chemical simplicity and ability to exchange genetic information with itself and RNA. Here, we have applied Darwinian evolution methods to evolve, in vitro, a TNA receptor that binds to an arbitrary target with high affinity and specificity. This demonstration shows that TNA has the ability to fold into tertiary structures with sophisticated chemical functions, which provides evidence that TNA could have served as an ancestral genetic system during an early stage of life.

An RNA Aptamer-Based Microcantilever Sensor To Detect the Inflammatory Marker, Mouse Lipocalin‑2 Lipocalin-2 (Lcn2) is a biomarker for many inflammatory-based diseases, including acute kidney injury, cardiovascular stress, diabetes, and various cancers. Inflammatory transitions occur rapidly in kidney and cardiovascular disease, for which an in-line monitor could be beneficial. Microcantilever devices with aptamers as recognition elements can be effective and rapidly responsive sensors. Here, we have selected and characterized an RNA aptamer that specifically binds mouse Lcn2 (mLcn2) with a dissociation constant of 340 ± 70 nM in solution and 38 ± 22 nM when immobilized on a surface.

Computational and Experimental Analyses Converge to Reveal a Coherent Yet Malleable Aptamer Structure That Controls Chemical Reactivity As short nucleic acids, aptamers in solution are believed to be structurally flexible. Consistent with this view, most aptamers examined for this property have been shown to bind their target molecules by mechanisms that can be described as “induced fit”. But, it is not known to what extent this structural flexibility affects the integrity of the target-aptamer interaction. Using the malachite green aptamer (MGA)as a model system, we show that the MGA can protect its bound target, malachite green (MG), from oxidation over several days.

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