Two-Step Energy Transfer Dynamics in Conjugated Polymer and Dye-Labeled Aptamer-Based Potassium Ion Detection Assay

Abstract

We recently implemented highly sensitive detection systems for photo-sensitizing potassium ions (K+) based on two-step Förster resonance energy transfer (FRET). As a successive study for quantitative understanding of energy transfer processes in terms of the exciton population, we investigated the fluorescence decay dynamics in conjugated polymers and an aptamer-based 6-carboxyfluorescein (6-FAM)/6-carboxytetramethylrhodamine (TAMRA) complex. In the presence of K+ ions, the Guanine-rich aptamer enabled efficient two-step resonance energy transfer from conjugated polymers to dyed pairs of 6-FAM and TAMRA through the G-quadruplex phase. Although the fluorescence decay time of TAMRA barely changed, the fluorescence intensity was significantly increased. We also found that 6-FAM showed a decreased exciton population due the compensation of energy transfer to TAMRA by FRET from conjugated polymers, but a fluorescence quenching also occurred concomitantly. Consequently, the fluorescence intensity of TAMRA showed a 4-fold enhancement, where the initial transfer efficiency (~300%) rapidly saturated within ~0.5 ns and the plateau of transfer efficiency (~230%) remained afterward.

Fluorescence “turn-off/turn-on” biosensing of metal ions by gold nanoclusters, folic acid and reduced graphene oxide

“…Oligonucleotide aptamers [2,8], single-layer graphene [3], valinomycin [9], 18-Crown-6 ether [10], etc., are some of the sensing elements used for selective and sensitive detection of K þ . Triazacryptand (TAC) is typically used in designing biosensor for K þ , owing to its ability as a K þ binding ligand and selective response for K þ over competing for sodium ion (Na þ ) [1,11].…”

Influence of Diethyl Phthalate (DEP) on Fluorescence Emission Quenching of Poly Vinyl Chloride (PVC) in Solid Films

“…The radiative and non-radiative which involve all possible pathways of the fluorescence deactivation such as internal conversion, intersystem crossing, or other intra-and intermolecular quenching mechanisms. The mechanism of the quenching process includes energy transfer between fluorophore molecules (donor) in an electronically excited state to an adjacent quencher molecule (acceptor) [2][3][4]. When fluorophore molecule becomes excited, emits fluorescence, and a quencher will reduce that fluorescence by energy transfer from an excited species to another molecule [5].…”

Conjugated Polymers Containing Building Blocks 1,3,4,6-Tetraarylpyrrolo[3,2-b]pyrrole-2,5-dione (isoDPP), Benzodipyrrolidone (BDP) or Naphthodipyrrolidone (NDP): A Review

“…In the past few years, a growing number of chemists focus their attention on development new π-conjugated polymers for electronics applications [5,6,7,8,9,10,11,12]. Some of the most widely studied polymers are donor–acceptor (D–A) type polymers due to its intrinsic properties such as high charge transfer mobility.…”