Amplified fluorescence quenching in high ionic strength media

Wayne N. George, Mark Giles, Iain McCulloch, John C. De Mello*, Joachim H G Steinke

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


We report a new cationic poly(phenylene ethynylene) (PPE) derivative that exhibits strong amplified fluorescence quenching in the presence of electron-deficient species, yielding high Stern-Volmer coefficients of 4.7 × 107 M-1 in aqueous solutions. Importantly, with the addition of appropriate non-ionic surfactants, the polymer is found to retain its excellent sensitivity even when transferred to high ionic strength buffered media, which have previously been shown to suppress the amplified quenching effect in other polyelectrolyte systems. The cationic PPE derivative yields Stern-Volmer coefficients as high as 107 M-1 in 25 mM buffer solutions of both tris(hydroxymethyl) aminomethane (Tris) and sodium acetate containing 150 mM sodium chloride, the optimal conditions for many enzymes such as phosphatases. The ability to maintain high Stern-Volmer coefficients in high ionic strength buffered media extends the applicability of ionic conjugated polymers to high sensitivity detection in biological media, and thus greatly enhances their versatility as biological sensors.

Original languageEnglish (US)
Pages (from-to)1381-1387
Number of pages7
JournalSoft Matter
Issue number11
StatePublished - 2007
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry (miscellaneous)


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