A Pyrene‐Labeled G‐Quadruplex Oligonucleotide as a Fluorescent Probe for Potassium Ion Detection in Biological Applications

Abstract

Ionensonde: Ein Kalium‐empfindliches Oligonucleotid mit terminalen Pyreneinheiten kann als Fluoreszenzsonde für die Verfolgung der extrazellulären Konzentration von K+‐Ionen in Echtzeit unter physiologischen Bedingungen genutzt werden. Die Intensität der Excimer‐Emission (b) der gebildeten stuhlförmigen Quadruplexstruktur hängt von der K+‐Ionenkonzentration (0–200 mM) ab und unterscheidet sich deutlich von der ohne Kalium gemessenen Intensität (a).

G Quadruplex‐Based FRET Probes with the Thrombin‐Binding Aptamer (TBA) Sequence Designed for the Efficient Fluorometric Detection of the Potassium Ion

“…[10,15] Interestingly, upon addition of K + , negative and positive peaks appeared (490 and 560 nm respectively) that corresponded to the FAM and TAMRA dyes, respectively. Human A C H T U N G T R E N N U N G telomere tetraplexes carrying FAM and TAMRA dyes described in previous papers exhibited a similar peculiarity, [3,8,20] which was attributed to the interactions between FAM and TAMRA dyes after forming the tetraplex structure.…”

“…[8,9] In a subsequent fluorescent probe (PSO-py), we exploited pyrene excimer emission for the transduction of the cation binding by the 15-mer thrombin-binding aptamer (TBA; d(GGTTGGTGTGGTTGG)). [10] Unlike in the FRET approach, stacking interactions between fluorophores (pyrene) were advantageous and produced efficient excimer emission. Due to the orientation of pyrene rings the PSO-py/K + complex emitted excimer fluorescence, while the random-coil structure of PSO-py in the absence of K + gave only monomer emission.…”

An Aptamer-based and Pyrene-labeled Fluorescent Biosensor for Homogeneous Detection of Potassium Ions

“…For Na + , Ca 2+ , Mg 2+ and NH4 + ions, the changes of relative excimer-emission intensities were very weak due to their weak binding affinity with thrombin-binding aptamer. 8,31 Hence, the proposed method represents good specificity for K + ions over Na + , Mg 2+ , Ca 2+ , and NH4 + ions at experimental condition. K + ions coexist with an excess of Na + ions in extracellular conditions.…”

“…[5][6][7] In 2005, Nagatoishi et al reported thrombin-binding aptamer labeled by pyrene moieties at both ends for the detection of potassium in the presence of an excess of Na + . 8 However, these methods were greatly limited in their applicability because modified aptamers may cause reduction of affinity and specificity. [9][10][11][12] Recently, Shi et al reported an aptamer-based optical biosensor for K + detection, in which aptamer was unmodified as the molecular recognition element.…”

A ratiometric fluorescence assay for acetylcholinesterase activity and inhibitor screening based on supramolecular assembly induced monomer–excimer emission transition of a perylene probe

“…It is worth noting that there is no clear isoemissive point at around 640 nm because it is a more complex system than the simple two-component excimermonomer equilibrium. 43 Maximum I M /I E value was observed aer 180 min of enzymatic reaction (Fig. 3b).…”