Engineering Signaling Aptamers That Rely on Kinetic Rather Than Equilibrium Competition
| Autor: | Andrew D. Ellington, Michelle Byrom, Yu Sherry Jiang, Shu Jun Zhen, Bingling Li, Yan Du |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Aptamer
Nanotechnology Biosensing Techniques Ricin 02 engineering and technology Ligands 010402 general chemistry Binding Competitive 01 natural sciences Analytical Chemistry Limit of Detection Ligand Oligonucleotide Chemistry Electrochemical Techniques Aptamers Nucleotide Oligonucleotides Antisense 021001 nanoscience & nanotechnology 0104 chemical sciences Kinetics Binding conformation Duplex (building) Molecular Probes Antisense oligonucleotides Biophysics Thermodynamics 0210 nano-technology Molecular probe |
| Zdroj: | Analytical Chemistry. 88:2250-2257 |
| ISSN: | 1520-6882 0003-2700 |
| DOI: | 10.1021/acs.analchem.5b03930 |
| Popis: | During the past decade, aptasensors have largely been designed on the basis of the notion that ligand-modulated equilibration between aptamer conformations could be exploited for sensing. One implementation of this strategy has been to denature the aptamer with an antisense oligonucleotide, wait for dissociation of the antisense oligonucleotide, and stabilize the folded, signaling conformer with a ligand. However, there is a large kinetic barrier associated with releasing the oligonucleotide from the aptamer to again obtain an active, binding conformation. If the length of the antisense oligonucleotide is decreased to make dissociation from the aptamer more favorable, higher background signals are observed. To improve the general methodology for developing aptasensors, we have developed a novel and robust strategy for aptasensor design in which an oligonucleotide kinetically competes with the ligand for binding rather than having to be released from a stable duplex. While the oligonucleotide can induce conformational change, it initially chooses between the aptamer and a molecular beacon (MB), a process that does not require a lengthy pre-equilibration. Using an anti-ricin aptamer as a starting point, we developed a "competitive" aptasensor with a measured limit of detection (LOD) of 30 nM with an optical readout and as low as 3 nM for ricin toxin A-chain (RTA) detection on an electrochemical platform. |
| Databáze: | OpenAIRE |
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