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Amplified fluorescence quenching in high ionic strength media
Wayne N George1, Mark Giles2, Iain McCulloch2
1Department of Chemistry, Imperial College London, South Kensington, London, UKSW7 2AZ. j.demello@imperial.ac.uk j.steinke@imperial.ac.uk.
Soft Matter
|September 9, 2020
Summary
A new cationic polymer shows strong fluorescence quenching for detecting electron-deficient species. It maintains high sensitivity in biological conditions, enhancing its use as a versatile biological sensor.
Area of Science:
- Materials Science
- Analytical Chemistry
- Biotechnology
Background:
- Conjugated polymers are widely used in sensing applications.
- Polyelectrolyte systems often suffer from reduced sensitivity in high ionic strength media.
- Amplified fluorescence quenching is a sensitive detection method.
Purpose of the Study:
- To develop a cationic poly(phenylene ethynylene) (PPE) derivative with enhanced fluorescence quenching.
- To investigate the polymer's performance in high ionic strength buffered media.
- To improve the applicability of conjugated polymers as biological sensors.
Main Methods:
- Synthesis of a novel cationic PPE derivative.
- Measurement of fluorescence quenching efficiency and Stern-Volmer coefficients in aqueous solutions.
- Evaluation of polymer performance in the presence of non-ionic surfactants in buffered solutions with high salt concentrations.
Main Results:
- The cationic PPE derivative exhibited strong amplified fluorescence quenching with high Stern-Volmer coefficients (4.7 × 10^4 M) in aqueous solutions.
- The polymer retained excellent sensitivity in high ionic strength buffered media (25 mM Tris/sodium acetate, 150 mM NaCl) with Stern-Volmer coefficients up to 10^5 M.
- Non-ionic surfactants were crucial for maintaining sensitivity in buffered media.
Conclusions:
- The developed cationic PPE derivative offers high sensitivity for detecting electron-deficient species.
- The polymer's ability to function in high ionic strength buffered media significantly broadens its application scope.
- This advancement enhances the versatility of ionic conjugated polymers for high-sensitivity biological sensing.
