A homogeneous assay is reported using Ru(phen)(2)(dppz)(2+) and a K(+)-binding aptamer for the selective and sensitive detection of a target oligonucleotide and potassium ions, based on reduction in fluorescence emission according to the formation of the G-quadruplex structure from the aptamer in the presence of K(+).

Here we tested the ability to augment the biological activity of the thrombin aptamer, d(GGTTGGTGTGGTTGG), by using locked nucleic acid (LNA) to influence its G-quadruplex structure. Compared to un-substituted control aptamer, LNA-containing aptamers displayed varying degrees of thrombin inhibition. Aptamers with LNA substituted in either positions G5, T7, or G8 showed decreased thrombin inhibi...

Aptamer-based electrochemical sensors are now developed for the detection of a wide variety analytes including ions, low-molecular-weight molecules, proteins, and living cells. An aptamer-based sensor is an analytical device whose bio-sensing element (i.e. aptamer) immobilized on transducer surface. Aptasensors have attracted great attention because their high selectivity, sensitivity, stabilit...

AGRO100 (also known as AS1411) is a G-rich oligonucleotide that has long been established as a potent anti-cancer aptamer. However, the structure of AGRO100 remained unresolved, due to the co-existence of multiple different G-quadruplex conformations. We identified a DNA sequence named AT11, derived from AGRO100, which formed a single major G-quadruplex conformation and exhibited a similar anti...

Bisphenol A (BPA) detection in drinking water and food packaging materials has attracted much attention since the discovery that BPA can interfere with normal physiological processes and cause adverse health effects. Here, we constructed a label-free aptamer fluorescent assay for selective and sensitive detection of BPA based on the rolling circle amplification (RCA)/Exonuclease III (Exo III)-c...

G-Quadruplex (G-4) structures are formed when G-rich DNA sequences fold into intra- or intermolecular four-stranded structures in the presence of metal ions. G-4-hemin complexes are often effective peroxidase-mimicking DNAzymes that are applied in many detection systems. This work reports the application of a G-rich daunomycin-specific aptamer for the development of an antibody-antigen detectio...

In situ fabricated nucleic acids microarrays are versatile and very high-throughput platforms for aptamer optimization and discovery, but the chemical space that can be probed against a given target has largely been confined to DNA, while RNA and non-natural nucleic acid microarrays are still an essentially uncharted territory. 2΄-Fluoroarabinonucleic acid (2΄F-ANA) is a prime candidate for suc...

Aqueous interfaces of stimuli-responsive, thermotropic nematic liquid crystals (LC) have been utilized in the design biosensing platforms for a range analytes. Owing to orientational changes LC, these can easily report aptamer-target binding events at LC-aqueous interface. We demonstrate label-free, simple and robust technique detection Ochratoxin A (OTA) using aptamer as recognition probe. The...

To obtain an aptamer with a high affinity for vascular endothelial growth factor (VEGF), we focused on the receptor-binding domain (RBD) of VEGF as a target epitope. Three rounds of screening gave Vap7, which bound to the VEGF isoforms VEGF(121) and VEGF(165) with K(D) values of 1.0 nM and 20 nM, respectively. Moreover, Vap7 showed specificity within the VEGF family. Secondary structure predict...