Surface plasmon-coupled directional emission based on a conformational-switching signaling aptamer

Abstract

We have observed highly polarized and directional surface plasmon-coupled emission of a signaling aptamer due to the binding of a target thrombin with the aptamer, which induces conformational switching.

Hg(II)-activated emission “turn-on” chemosensors excited by up-conversion nanocrystals: Synthesis, characterization and sensing performance

“…3, the R 0 values are calculated as 19 Å for host:4 and 22 Å for host:5, respectively. Both Forester radii are slightly shorter than literature values, suggesting that a high concentration of host:chemosensor mixture is needed to guarantee an efficient energy transfer between them [21][22][23][24].…”

Towards two up-conversion optical sensing systems for cysteine detection: Synthesis, characterization and sensing performance

“…Here, parameters of Q 0 , J, 2 , n d , N A , , f d (), A () stand for host intrinsic emission yield (3%, as reported by Boyer), spectral overlap integral between host emission and chemosensor absorption, mutual molecular orientation, solvent refraction index, Avogadro number, wavelength, host emission intensity and chemosensor molar extinction efficient, respectively [20,21]. With emission and absorption spectra on hand, R 0 values are calculated as 20 Å for R-1 and 19 Å for R-2, respectively.…”

“…In virtue of their structural transformation between a spirolactam structure (non-emissive) and a delocalized xanthene structure (emissive), rhodamine and its derivatives have been proved as promising chemosensors by showing emission turn-on effect towards analyte targets [17][18][19][20]. The primitive objective of this work is to construct sensing systems with limited photobleaching effect.…”

“…NaYF 4 excitation host was synthesized following a literature method [18][19][20]. Below reagents were mixed together, heated to 160 • and kept for 30 min under N 2 protection, including 1-octadecene (15 mL), oleic acid (6 mL), ErCl 3 ·6H 2 O (0.02 mmol), YbCl 3 ·6H 2 O (0.20 mmol) and YCl 3 ·6H 2 O (0.78 mmol).…”

Nucleotides and nucleic acids; oligo- and polynucleotides

“…320 The binding of thrombin to a fluorescently-labelled but quenched aptamer sequence resulted in a fluorescent signal on binding as well as an enhanced surface plasmon-coupled emission. 321 In addition, an intercalating dye (Genefinder) has been used as a method for protein detection using a duplex DNA that encodes a thrombin aptamer. 322 The role of sugar pucker in the thrombin aptamer has been probed using North and South conformationally locked nucleosides (78, North analogue shown), and whilst the aptamer was relatively accommodating towards the South-locked nucleosides, in one position the North-locked nucleoside completely destabilised the aptamer.…”