Most of the conjugated polymer employed as fluorescent biosensors present low solubility and emission in aqueous environment. In order to solve this feature, we have reconstituted, in buffer phosphate, a neutral conjugated poly[9,9- bis(6'-bromohexil)-2,7-fluorene-co-alt-1,4-phenylene], as PFPBr₂ (insoluble in water), in the presence of an artificial zwitterionic phospholipids bilayers, as 1,2-dimyristoyl-sn-glycero-3-phospho-choline (DMPC). Quantum yield of PFPBr₂-DMPC was around 20% in phosphate buffer, it was identical value calculated from ammonium polyelectrolytes (PFPNMe³⁺). In addition, the maximum of bluish emission for buffer solution of PFPBr₂-DMPC was at 420nm, a red-shift emission with regard to chloroform solution (at 410 nm). The structural study at different concentrations of PFPBr₂ and DMPC was carried out using different approaches: steady state fluorescence spectroscopy, confocal fluorescence microscopy and calorimetry. A positive interaction takes place involving neutral conjugated polymer and zwitterionic phospholipids bilayer. Novels complexes or associations of poly(fluorene-phenylene) (PFPBr₂) and zwitterionic phospholipids (DMPC) have been suggested and visualized by epifluorescence. Phase transitions of the liposomes have been also detected by differential scanning calorimetry.

Date Published: 22 May 2007
PDF: 8 pages
Proc. SPIE 6592, Bioengineered and Bioinspired Systems III, 659213 (22 May 2007); doi: 10.1117/12.721505

Published in SPIE Proceedings Vol. 6592:
Bioengineered and Bioinspired Systems III
Paolo Arena; Ángel Rodríguez-Vázquez; Gustavo Liñán-Cembrano, Editor(s)