Oligonucleotide‐mediated aggregation of a cationic conjugated polymer for fluorescent detection of mercury ions in an aqueous medium

Abstract

A cationically charged conjugated polymer (P2) functionalized with quaternary ammonium salt was newly synthesized via Suzuki cross‐coupling polymerization. The functionalized P2 features different fluorescence colors according to its phases (blue emission in solution and green emission as asolid) which is caused by intramolecular and intermolecular exciton migration, respectively. The use of P2 as a novel fluorescent sensing platform is demonstrated for mercury ion detection. The detection of mercury ions is accomplished in two steps: (1) the cationic, blue‐emitting P2 absorbs an anionic oligonucleotide, polythymidine (PT) via electrostatic interaction to form a complex with green emission due to aggregation between the two species; (2) the addition of mercury ions to the complex produces a new complex of PT‐Hg2+ via more favorable specific interaction, resulting in the isolation of P2 and the consequent recovery of blue fluorescence of P2. It suggests that this detection system has high selectivity and sensitivity down to the ∼10−7 M level, even in mixtures of metal ions. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2393–2400

Biocompatible Nanoparticles Based on Diketo‐Pyrrolo‐Pyrrole (DPP) with Aggregation‐Induced Red/NIR Emission for In Vivo Two‐Photon Fluorescence Imaging

“…Owing to their exceptional thermal and photochemical stability, large extinction coeffi cients, and high fl uorescence quantum yields, DPP-based materials have received intensive research interests in the fi eld of light-emitting diodes, [ 18 ] solar cells, [ 19 ] and biosensors. [ 20 ] However, it is a great challenge to sustain the effi cient emission of DPP-based compounds in aggregated states due to the serious intermolecular π-π stacking.…”

Conjugated Polymer Dots-on-Electrospun Fibers as a Fluorescent Nanofibrous Sensor for Nerve Gas Stimulant

“…The long-wavelength emission was mainly afforded by the quinoxaline units, whose intensity was enhanced by the energy transfer from the fluorene units in the aggregated state. , The concentration dependency of the emission changes of PQ could be easily observed with the naked eye under UV illumination, as shown in Figure S1 (Supporting Information). This concentration-dependent or aggregation-induced emission change was attributed to the intermolecular exciton migration, which was triggered by aggregation between the polymer chains, as found in the conjugated polymers containing both electron donor (fluorene) and acceptor (quinoxaline) groups in the same backbone. − …”

Conjugated Poly(fluorene-quinoxaline) for Fluorescence Imaging and Chemical Detection of Nerve Agents with Its Paper-Based Strip

“…As a result of intermolecular energy transfer in the aggregated polymers, blue-to-green or blue-to-red emission changes of conjugated polymers have been observed. This was subsequently used for the detection of biologically relevant species. − On the basis of this mechanism, our group reported the synthesis of anionically charged conjugated polyelectrolytes composed of larger amounts of electron-donating phenylene units and relatively smaller amounts of electron-accepting benzothiadiazole or bisthienylbenzothiadiazole segments to facilitate blue-to-green or blue-to-red emission color assays for mercury ions, proteins, and amino acids. ,− …”