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Preparation of Neutrally-charged, pH-responsive Polymeric Nanoparticles for Cytosolic siRNA Delivery
Published on: May 2, 2019
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Redox-responsive, reversibly-crosslinked thiolated cationic helical polypeptides for efficient siRNA encapsulation
Nan Zheng1, Ziyuan Song1, Yang Liu1
1Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, 1304 W Green Street, Urbana, IL 61801, USA.
Summary
Researchers developed stable polypeptide/siRNA complexes using disulfide crosslinking. These complexes protect siRNA from degradation and enable efficient gene silencing via redox-responsive release, offering a promising strategy for siRNA delivery.
Area of Science:
- Biotechnology
- Molecular Biology
- Drug Delivery
Background:
- Cationic helical polypeptides efficiently penetrate cell membranes but struggle to stably condense siRNA.
- This instability limits gene knockdown efficiency due to poor siRNA protection and delivery.
- Existing methods often compromise polypeptide structure or membrane activity.
Purpose of the Study:
- To develop stable polypeptide/siRNA complexes that overcome condensation limitations.
- To enhance siRNA protection against nuclease degradation.
- To achieve efficient intracellular siRNA release and gene silencing.
Main Methods:
- Thiolated polypeptides were crosslinked via disulfide bonds after forming polypeptide/siRNA complexes.
- Complex stability, secondary structure, and membrane activity were assessed.
- Nuclease protection, cellular uptake, endosomal escape, and gene silencing efficacy were evaluated in vitro.
Main Results:
- Stable, crosslinked polypeptide/siRNA complexes were successfully formed without compromising helical structure or membrane activity.
- The complexes effectively protected siRNA from nuclease digestion while maintaining cellular internalization and endosomal escape.
- Redox-responsive siRNA release was observed intracellularly, mediated by glutathione (GSH), leading to efficient gene silencing with low cytotoxicity.
Conclusions:
- Disulfide crosslinking provides a stable yet redox-responsive platform for polypeptide/siRNA complexes.
- This approach enhances siRNA protection and facilitates efficient intracellular delivery and gene silencing.
- The developed strategy offers a promising method for polypeptide-based siRNA delivery systems.
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