Efficient Receptor Mediated siRNA Delivery in Vitro by Folic Acid Targeted Pentablock Copolymer-Based Micelleplexes

Area of Science:

• Biomaterials Science
• Nanotechnology
• Gene Therapy

Background:

• Developing effective and safe delivery systems for small interfering RNA (siRNA) is crucial for RNA interference (RNAi) therapies.
• Polymeric nanoparticles offer potential for nucleic acid delivery but often face challenges with stability and non-specific interactions.

Purpose of the Study:

• To design and develop novel, biocompatible polyplexes for target-specific siRNA delivery.
• To evaluate the stability, targeting efficiency, and gene silencing capability of the developed nanocarriers.

Main Methods:

• Synthesis of cationic pentablock copolymers and folic acid functionalized copolymers.
• Formation of micelleplexes with a hydrophobic core and shielded cationic/hydrophilic layers.
• Assessment of particle stability in serum and gene knockdown efficacy in GFP-expressing HeLa cells.
• Investigation of cellular uptake mechanisms using receptor-mediated endocytosis in HeLa and HEK293 cells.

Main Results:

• The developed micelleplexes demonstrated high stability in complete serum over 24 hours, outperforming polyethyleneimine (PEI).
• Targeted siRNA delivery resulted in approximately 31% suppression of GFP expression in HeLa cells, compared to 8% for non-targeted micelleplexes.
• Receptor-mediated cellular uptake was confirmed through comparative studies using folic-receptor positive HeLa cells and negative HEK293 cells.
• The nanocarrier exhibited no cytotoxicity.

Conclusions:

• The novel polyplexes provide a stable and biocompatible platform for targeted siRNA delivery.
• The combination of a stealth shielding layer and folic acid targeting moiety effectively overcomes common challenges in polymeric nucleic acid delivery systems.
• This approach holds significant potential for in vivo RNA inhibition applications, minimizing undesired protein and cell interactions.