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Efficient gene transfer using reversibly cross-linked low molecular weight polyethylenimine
1College of Pharmacy, Division of Pharmaceutics and Pharmaceutical Chemistry, The Ohio State University, Columbus, Ohio 43210, USA.
Bioconjugate Chemistry
|November 22, 2001
Summary
Cross-linking low molecular weight polyethylenimine (PEI) with specific reagents enhances its efficiency as a nonviral gene delivery vector. Conjugate size correlated with gene transfer, and disulfide bond reduction impacted DNA condensation.
Area of Science:
- Biotechnology
- Materials Science
- Molecular Biology
Background:
- Polyethylenimine (PEI) is a promising polycation for nonviral gene delivery.
- Developing efficient and safe gene delivery vectors is crucial for therapeutic applications.
Purpose of the Study:
- To investigate the efficacy of cross-linked low molecular weight PEI as an in vitro gene delivery vector.
- To evaluate the impact of different cross-linking reagents and conjugation ratios on transfection efficiency.
Main Methods:
- Conjugation of low molecular weight PEI with dithiobis(succinimidylpropionate) (DSP) and dimethyl.3,3'-dithiobispropionimidate*2HCl (DTBP).
- Transfection of Chinese hamster ovary (CHO) cells using a luciferase reporter gene.
- Gel retardation analysis to assess DNA condensation capacity before and after reduction.
Main Results:
- Cross-linked PEI conjugates demonstrated variable in vitro gene delivery efficiencies.
- Gene transfer efficiency was generally proportional to the size of the PEI conjugate.
- Reduction of disulfide bonds with dithiothreitol (DTT) affected DNA condensation, particularly for DSP-cross-linked polymers.
Conclusions:
- Homobifunctional amine-reactive reducible cross-linking reagents can enhance PEI-mediated gene delivery.
- The choice of cross-linker, conjugation extent, and N/P ratio are critical factors influencing transfection.
- Disulfide bond reduction may play a role in facilitating PEI uncoupling from DNA post-transfection.