Adaptive Recognition of Small Molecules by Nucleic Acid Aptamers through a Label‐Free Approach

Abstract

We report a novel label-free method for the investigation of the adaptive recognition of small molecules by nucleic acid aptamers using capillary electrophoresis analysis. Cocaine and argininamide were chosen as model molecules, and the two corresponding DNA aptamers were used. These single-strand DNAs folded into their specific secondary structures, which were mainly responsible for the binding of the target molecules with high affinity and specificity. For molecular recognition, the nucleic acid structures then underwent additional conformational changes, while keeping the target molecules stabilized by intermolecular hydrogen bonds. The intrinsic chemical and physical properties of the target molecules enabled them to act as indicators for adaptive binding. Thus any labeling or modification of the aptamers or target molecules were made obsolete. This label-free method for aptamer-based molecular recognition was also successfully applied to biological fluids and therefore indicates that this approach is a promising tool for bioanalysis.

Electrochemical Aptasensor for the Determination of Cocaine Incorporating Gold Nanoparticles Modification

“…3, curve f). This is probably attributed to the fact that the interaction of the Fc-aptamer with positively charged cocaine (pK a % 8.6) [32] leads to decrease of negative charge of anionic phosphates of the aptamer, which facilitates access the negatively charged marker to the surface of the electrode, resulting at a decrease of R et . This result obtained is in good agreement with those described by Wang et al, who used Faradaic Impedance Spectroscopy for the detection of lysozyme [14].…”

Separation and Detection of Narcotic Drugs on a Microchip Using Micellar Electrokinetic Chromatography and Electrochemiluminescence

“…Both cocaine and its hydrolysate ecgonine can generate strong ECL emission, and they have been separated on conventional CZE using 20 mM phosphate (pH 7.0) as running buffer as previously reported, and the maximal ECL emission was observed at pH 8.5 [25]. But, unfortunately, as shown in Figure 2a, cocaine and ecgonine can not be separated on the CZE microchip under the same experimental condition owing to the much shorter separation channel on the microchip.…”

Ru(bpy)32+‐doped Silica Nanoparticle Aptasensor for Detection of Thrombin Based on Electrogenerated Chemiluminescence

“…[16][17][18] But the combination of high sensitive ECL technique with an aptamer was seldom recorded in literatures. [19][20][21] To the best of our knowledge, ECL-based aptasensor for the determination of thrombin is rarely reported. 22 The combination of nanotechnology and biotechnology for the detection of biological elements has brought new opportunities.…”