Stabilization of Neutral Polyfluorene in Aqueous Solution through Their Interaction with Phospholipids and Sol鈥揋el Encapsulation

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• 作者：Ricardo Mallavia ; Maria Jos茅 Mart铆nez-Tom茅 ; Rebeca V谩zquez-Guill贸 ; Zehra Kahveci ; Amparo Estepa ; C. Reyes Mateo
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2013
• 出版时间：April 24, 2013
• 年：2013
• 卷：5
• 期：8
• 页码：2952-2958
• 全文大小：330K
• 年卷期：v.5,no.8(April 24, 2013)
• ISSN：1944-8252

文摘

Interaction between poly[9,9-bis(6鈥?bromohexyl)-2,7-fluorene-co-alt-1,4-phenylene] (PFPBr<sub>2sub>), a neutral conjugated polyfluorene which is completely insoluble in water, and zwitterionic phospholipids has been investigated in order to generate new fluorescent structures which are stable in aqueous media as a means of extending the biological applications of these kinds of polymers. Two types of differently shaped and composed fluorescent structures were identified and then isolated and characterized separately using different biophysical techniques. The first structure type, corresponding to liposomal complexes, showed a fluorescence band centered around 405 nm and maximum absorption at 345 nm, while the second, corresponding to polymer鈥損hospholipid aggregates of variable sizes with lower lipid content, absorbed at longer wavelengths and displayed a well resolved fluorescence spectrum with a maximum centered at 424 nm. Both structures were stable in a large range of pH, and their fluorescence intensity remained practically unaltered for 10 days; it then began to decrease, which was probably because of aggregation. Encapsulation of these structures within the pores of a sol鈥揼el matrix did not affect their fluorescent properties but increased their stability, avoiding further aggregation and subsequent precipitation.

Keywords:

polyfluorene; phospholipid; liposomes; sol鈭抔el matrix; stabilization; encapsulation