scholarly journals DNA aptamer-based rolling circle amplification product as a novel immunological adjuvant

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Adil S. Al-Ogaili ◽  
Rohana Liyanage ◽  
Jack O. Lay ◽  
Tieshan Jiang ◽  
Christine N. Vuong ◽  
...  
Keyword(s):  
Binding Affinity ◽  
Specific Binding ◽  
Rolling Circle Amplification ◽  
Dna Aptamer ◽  
Infection Model ◽  
Dna Aptamers ◽  
Igg Antibody ◽  
Rolling Circle ◽  
Acquired Immune Responses ◽  
Line P

AbstractSeveral agonists to CD40 have shown to induce acquired immune responses. Here, we developed and evaluated the rolling circle amplification (RCA) products that are based on anti-CD40 DNA aptamers as a novel vaccine adjuvant. First, we developed DNA aptamers with specific binding affinity to chicken CD40 extra domain (chCD40ED). Next, we prepared the RCA products that consist of these aptamers to increase the spanning space and overall binding affinity to chCD40ED. Using 8 DNA aptamer candidates, 4 aptamer-based RCA products (aptamer RCAs) were generated, each consisting of two distinct aptamers. We demonstrated that all 4 aptamer RCAs significantly induced the signal transduction in chicken HD11 macrophage cell line (p < 0.05). Finally, we conjugated one of the aptamer RCAs (Aptamer RCA II) to M2e epitope peptide of influenza virus as a model hapten, and the immune complex was injected to chickens. Aptamer RCA II stimulated anti-M2e IgG antibody production to the level significantly higher as compared to the control (M2e epitope alone; p < 0.05). The results of our work suggest that aptamer RCA is a novel platform to boost the efficacy of vaccines, which might find broad applications to other antigens beyond M2e epitope evaluated in this study using chicken infection model.

scholarly journals Characterization of Binding of Magnetic Nanoparticles to Rolling Circle Amplification Products by Turn-On Magnetic Assay

Biosensors ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 109 ◽  
Author(s):  
Sobhan Sepehri ◽  
Björn Agnarsson ◽  
Teresa Zardán Gómez de la Torre ◽  
Justin F. Schneiderman ◽  
Jakob Blomgren ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Specific Binding ◽  
Ac Susceptibility ◽  
Rolling Circle Amplification ◽  
Rolling Circle ◽  
Low Concentrations ◽  
Assay Performance ◽  
Particle Ensemble ◽  
Kinetics Of

The specific binding of oligonucleotide-tagged 100 nm magnetic nanoparticles (MNPs) to rolling circle products (RCPs) is investigated using our newly developed differential homogenous magnetic assay (DHMA). The DHMA measures ac magnetic susceptibility from a test and a control samples simultaneously and eliminates magnetic background signal. Therefore, the DHMA can reveal details of binding kinetics of magnetic nanoparticles at very low concentrations of RCPs. From the analysis of the imaginary part of the DHMA signal, we find that smaller MNPs in the particle ensemble bind first to the RCPs. When the RCP concentration increases, we observe the formation of agglomerates, which leads to lower number of MNPs per RCP at higher concentrations of RCPs. The results thus indicate that a full frequency range of ac susceptibility observation is necessary to detect low concentrations of target RCPs and a long amplification time is not required as it does not significantly increase the number of MNPs per RCP. The findings are critical for understanding the underlying microscopic binding process for improving the assay performance. They furthermore suggest DHMA is a powerful technique for dynamically characterizing the binding interactions between MNPs and biomolecules in fluid volumes.

Arrest of Rolling Circle Amplification by Protein-Binding DNA Aptamers

2014 ◽  
Vol 20 (9) ◽  
pp. 2420-2424 ◽  
Author(s):  
Lida Wang ◽  
Kha Tram ◽  
Monsur M. Ali ◽  
Bruno J. Salena ◽  
Jinghong Li ◽  
...  
Keyword(s):  
Protein Binding ◽  
Rolling Circle Amplification ◽  
Dna Aptamers ◽  
Rolling Circle

scholarly journals Improving the Analytical Performance of Weak Aptamers: DNA Isothermal Amplification Approaches

Proceedings ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 26
Author(s):  
Ramón Lorenzo-Gómez ◽  
Rebeca Miranda-Castro ◽  
Noemí de-los-Santos-Álvarez ◽  
María Jesús Lobo-Castañón
Keyword(s):  
Magnetic Beads ◽  
Rolling Circle Amplification ◽  
Binding Constants ◽  
Isothermal Amplification ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Tumor Biomarker ◽  
Dna Aptamers ◽  
Rolling Circle ◽  
Neutrophil Gelatinase Associated Lipocalin ◽  
Potential Biomarker

Affinity characterization is an essential but time-consuming task to develop reliable aptamers for tumor biomarker detection and is not always thoroughly addressed. For neutrophil gelatinase-associated lipocalin (NGAL), a potential biomarker of pancreatic cancer, two DNA aptamers were described with very different affinity. Likewise, another pair of DNA aptamers was developed with very different affinity for alpha-fetoprotein (AFP), a biomarker of hepatocellular carcinoma. In this work, we estimated the dissociation constant of these aptamers by means of a direct assay on magnetic beads modified with biomarker and electrochemical detection on screen-printed carbon electrodes. In order to improve the performance of these aptamers, we proposed the isothermal amplification of the aptamers for both biomarkers by rolling circle amplification (RCA). In the case of AFP aptamers, we also tried terminal deoxynucleotidyl transferase (TdT), a template-independent amplification. Both DNA amplifications improved the sensitivity and the apparent binding constants of the aptamers for the two cancer biomarkers. Nevertheless, this improvement depends on the true affinity of the binding pair, which ultimately limits their analytical usefulness.

scholarly journals DNA aptamer-based carrier for loading proteins and enhancing the enzymatic activity

RSC Advances ◽  
2017 ◽  
Vol 7 (3) ◽  
pp. 1643-1645 ◽  
Author(s):  
Jieun Kim ◽  
Dajeong Kim ◽  
Jong Bum Lee
Keyword(s):  
Enzymatic Activity ◽  
Rolling Circle Amplification ◽  
Dna Aptamer ◽  
Rolling Circle ◽  
Thrombin Activity

Here, we synthesized DNA microparticles comprised of thrombin binding aptamers via rolling circle amplification (RCA). These DNA aptamer particles could successfully load a number of thrombins and the complexes have shown improved thrombin activity.

Ferromagnetic Resonance Biosensor for Homogeneous and Volumetric Detection of DNA

2017 ◽  
Author(s):  
Bo Tian ◽  
Peter Svedlindh ◽  
Mattias Strömberg ◽  
Erik Wetterskog
Keyword(s):  
Magnetic Nanoparticles ◽  
Ferromagnetic Resonance ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Rolling Circle Amplification ◽  
Resonance Field ◽  
Isothermal Amplification ◽  
Detection Sensitivity ◽  
Serum Samples ◽  
Rolling Circle

In this work, we demonstrate for the first time, a ferromagnetic resonance (FMR) based homogeneous and volumetric biosensor for magnetic label detection. Two different isothermal amplification methods, <i>i.e.</i>, rolling circle amplification (RCA) and loop-mediated isothermal amplification (LAMP) are adopted and combined with a standard electron paramagnetic resonance (EPR) spectrometer for FMR biosensing. For RCA-based FMR biosensor, binding of RCA products of a synthetic Vibrio cholerae target DNA sequence gives rise to the formation of aggregates of magnetic nanoparticles. Immobilization of nanoparticles within the aggregates leads to a decrease of the net anisotropy of the system and a concomitant increase of the resonance field. A limit of detection of 1 pM is obtained with an average coefficient of variation of 0.16%, which is superior to the performance of other reported RCA-based magnetic biosensors. For LAMP-based sensing, a synthetic Zika virus target oligonucleotide is amplified and detected in 20% serum samples. Immobilization of magnetic nanoparticles is induced by their co-precipitation with Mg<sub>2</sub>P<sub>2</sub>O<sub>7</sub> (a by-product of LAMP) and provides a detection sensitivity of 100 aM. The fast measurement, high sensitivity and miniaturization potential of the proposed FMR biosensing technology makes it a promising candidate for designing future point-of-care devices.<br>

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