Cationic and Anionic Conjugated Polyelectrolytes: Aggregation-Mediated Fluorescence Energy Transfer to Dye-Labeled DNA

✍ Scribed by Youngeup Jin; Renquiang Yang; Hongsuk Suh; Han Young Woo

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 214 KB
• Volume: 29
• Category: Article
• ISSN: 1022-1336
• DOI: 10.1002/marc.200800215

✦ Synopsis

Abstract

An electrostatic complex of water‐soluble conjugated polyelectrolytes (CPs) between anionic poly(9,9‐bis(4′‐sulfonatobutyl)fluorene‐co‐alt‐1,4‐phenylene) disodium salt (a‐PFP) and cationic poly(9,9‐bis((6′‐N,N,N,‐trimethylammonium)hexyl)fluorene‐co‐2,1,3‐bezothiadiazole) dibromide (85:15) (c‐PFB~15~) was tested as a fluorescence resonance energy transfer (FRET) donor to Texas Red (TR)‐labeled single‐stranded DNA (ssDNA‐TR) via two‐step FRET processes. Electrostatic complexation of a‐PFP and c‐PFB~15~ in water leads to aggregation of polymer chains, a concomitant reduction of intersegment distances, and energy transfer to the benzothiadiazole (BT) segments. The following complexation with ssDNA‐TR leads to energy transfer from BT to TR via two‐step FRET processes. This detection schematic shows an FRET‐induced signal amplification, which can be achieved by adjusting the charge ratio in the cationic/anionic CP complex and controlling the number density of the binding CPs around the acceptor, resulting in enhanced antenna effects and sensitivity in CP‐based FRET DNA detection assays.

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