In vivo delivery of functional Flightless I siRNA using layer-by-layer polymer surface modification

Area of Science:

• Biomaterials Science
• Gene Therapy
• Nanotechnology

Background:

• Gene silencing using small interfering RNA (siRNA) is a promising therapeutic strategy.
• Medical device implantation can trigger fibrotic processes.
• Effective delivery of siRNA to target tissues remains a challenge.

Purpose of the Study:

• To investigate layer-by-layer (LbL) polymer surface modification for siRNA delivery.
• To assess the potential of LbL-coated biomaterials to reduce fibrosis associated with medical devices.

Main Methods:

• LbL coating technique using siRNA and poly-L-lysine on tissue culture plates and polyurethane.
• In vitro assessment of green fluorescent protein (GFP) down-regulation.
• In vivo subcutaneous implantation of Rhodamine-labeled siRNA-coated polyurethane implants in mice.
• Analysis of cellular uptake, gene expression (Flii, TGF-β1, TGF-β3) in surrounding tissues.

Main Results:

• In vitro studies demonstrated dose-dependent GFP down-regulation with increasing LbL coatings.
• In vivo studies confirmed cellular uptake of Rhodamine-labeled siRNA within 2 days.
• Significant down-regulation of Flii gene expression observed up to 7 days post-implantation.
• Altered expression of downstream fibrotic genes (TGF-β1, TGF-β3) confirmed functional siRNA delivery.

Conclusions:

• LbL coating is a viable method for delivering siRNA via biomaterial surfaces.
• This approach can modulate the fibrotic response associated with medical device implantation.
• Demonstrates proof-of-principle for LbL-siRNA coatings in therapeutic applications.