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Fluorescence and thermotropic studies of the interactions of PEI-cholesterol based PEI-chol lipopolymers with dipalmitoyl phosphatidylcholine membranes

Bhattacharya, Santanu and Bajaj, Avinash (2008) Fluorescence and thermotropic studies of the interactions of PEI-cholesterol based PEI-chol lipopolymers with dipalmitoyl phosphatidylcholine membranes. In: Biochimica et Biophysica Acta, 1778 (10). pp. 2225-2233.

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Abstract

Numerous PEI derived polymers have been explored for their use in gene delivery. Nine PEI chol lipopolymers based on cholesterol grafting on three polyethyleneimines (PEI) of different molecular weights have been synthesized. Firstly their aggregation behavior has been studied using transmission electron microscopy and then their interactions with $L-\alpha-dipalmitoyl $phosphatidylcholine (DPPC) membranes have been examined using .uorescence anisotropy and differential scanning calorimetry (DSC). These PEI-chol lipopolymers are found to quench the chain motion of the acyl chains of DPPC, when incorporated in membranes, depending upon the cholesterol grafting on PEI. These PEI-chol lipopolymers act as .ller molecules in membranes. Electron microscopy shows the different aggregation behavior of these new PEI chol lipopolymers depending upon the molecular weight of PEI and percentage of cholesterol grafting. Detailed analysis of the .uorescence anisotropy and DSC data indicate that the nature of perturbation induced by PEI-chol lipopolymers is dependent upon the molecularweight of the PEI used and the % of cholesterol grafting on PEI. In general, PEI-chol lipopolymers rigidify the liquid-crystalline phase of the membranes without any noticeable effect on the gel phase unlike natural cholesterol, which is known to .uidize the gel phase of the membranes.

Item Type: Journal Article
Additional Information: copyright of this article belongs to Elsevier
Keywords: Liposomes;PEI-chol lipopolymers;Cholesterol;PEI;Membranes;Thermotropic properties;Anisotropy
Department/Centre: Division of Chemical Sciences > Organic Chemistry
Date Deposited: 19 Dec 2008 03:58
Last Modified: 19 Sep 2010 04:52
URI: http://eprints.iisc.ernet.in/id/eprint/16533

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