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

Bhattacharya, Santanu ; Bajaj , Avinash (2008) Fluorescence and thermotropic studies of the interactions of PEI-cholesterol based PEI-chol lipopolymers with dipalmitoyl phosphatidylcholine membranes Biochimica et Biophysica Acta: Biomembranes, 1778 (10). pp. 2225-2233. ISSN 0005-2736

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S00052...

Related URL: http://dx.doi.org/10.1016/j.bbamem.2008.05.005

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-a-dipalmitoyl phosphatidylcholine (DPPC) membranes have been examined using fluorescence 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 filler 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 fluorescence anisotropy and DSC data indicate that the nature of perturbation induced by PEI-chol lipopolymers is dependent upon the molecular weight 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 fluidize the gel phase of the membranes.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Liposomes; PEI-chol Lipopolymers; Cholesterol; PEI; Membranes; Thermotropic Properties; Anisotropy
ID Code:21050
Deposited On:20 Nov 2010 09:18
Last Modified:20 Nov 2010 09:18

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