Ionic Coating of siRNA Polyplexes with cRGD-PEG-Hyaluronic Acid To Modulate Serum Stability and In Vivo Performance

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Gene Therapy

Background:

• Efficient delivery of small interfering RNA (siRNA) polyplexes to tumors is hindered by bloodstream interactions, short circulation times, and poor biodistribution.
• Overcoming these challenges requires strategies to protect polyplexes and target them specifically to tumor sites.

Purpose of the Study:

• To develop and evaluate hyaluronic acid (HA)-coated polyplexes for enhanced tumor delivery and gene silencing.
• To investigate the role of HA coating, cyclic RGDfK (cRGD) peptide targeting, and polyethylene glycol (PEG) spacers in polyplex performance.

Main Methods:

• Development of sequence-defined oligoaminoamide polyplexes coated with ionic hyaluronic acid (HA).
• Modification of HA coating with cyclic RGDfK (cRGD) peptide and optional polyethylene glycol (PEG) spacers.
• Physicochemical characterization (zeta potential, siRNA retention), in vitro transfection efficiency, cellular uptake studies, and in vivo biodistribution and gene silencing in Neuro2a tumor-bearing mice.

Main Results:

• HA-coated polyplexes exhibited negative zeta potential and effective siRNA retention, unaffected by PEG or cRGD.
• In vitro studies showed enhanced tumor cell association, preserved transfection efficiency, and coating-dependent cellular internalization.
• In vivo studies demonstrated significantly increased tumor accumulation and gene silencing with HA-PEG-cRGD-coated polyplexes compared to uncoated polyplexes.

Conclusions:

• Hyaluronic acid coating provides a protective shield, enhancing serum stability and reducing nonspecific interactions of siRNA polyplexes.
• The addition of cRGD peptide facilitates targeted delivery to tumor endothelial cells, further improving tumor accumulation.
• HA-coated polyplexes, especially when functionalized with PEG and cRGD, represent a promising strategy for efficient in vivo siRNA delivery and gene silencing in tumors.