Modulation of charge density of cationic conjugated polyelectrolytes for improving the FRET-induced sensory signal with enhanced on/off ratio

Ji Eun Jeong, In Hwan Jung, Boram Kim, Van Sang Le, Han Young Woo

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Three types of cationic polyfluorenes with a different number of ionic groups are synthesized to modulate their solubility in water and the interactions with anionic oligonucleotide probes (DNA-C). Increasing the charge density improves the water-solubility of conjugated polyelectrolytes (CPEs) but decreases its optical antenna effect in the electrostatic sensory platform (CPE/DNA-C), resulting in low fluorescence resonance energy transfer (FRET) signal. With increasing charge density in CPE, the concentration of conjugated units in CPE/DNA-C decreases at [+]:[-] = 1:1, after which little driving force is expected to bring positive CPEs and negative DNA-C into close proximity for efficient FRET. CPF2 with 2 ionic groups (per repeat unit) and hydrophilic polyether side-chains exhibits good water-solubility and a higher FRET signal with an enhanced signal on/off ratio. In addition, the charge density in CPEs modulates the range of sensory responses by forming a tighter or weaker electrostatic CPE/DNA-C complex, which perturbs the probe-target binding interactions. Three types of cationic polyfluorenes with a different number of ionic groups are synthesized. In the conjugated polyelectrolyte (CPE) and DNA probe-based sensory system, ionic density of CPE (per repeat unit) needs to be controlled carefully to modulate the water-solubility, D-A intermolecular separation, and the resulting fluorescence resonance energy transfer sensory signal with high signal on/off ratio.

Original languageEnglish
Pages (from-to)459-466
Number of pages8
JournalMacromolecular Chemistry and Physics
Volume217
Issue number3
DOIs
Publication statusPublished - 2016 Feb 1

Keywords

  • conjugated polyelectrolytes
  • fluorescence resonance energy transfer
  • ionic density
  • on/off ratio
  • water-solubility

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Polymers and Plastics
  • Organic Chemistry
  • Materials Chemistry

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