Solid nano-in-nanoparticles for potential delivery of siRNA

Area of Science:

• Biotechnology
• Nanomedicine
• Drug Delivery Systems

Background:

• Small interfering RNA (siRNA) therapeutics show promise for genetic disorders but face challenges with cellular uptake and short circulation half-lives.
• Effective delivery systems are crucial for overcoming these limitations and realizing the therapeutic potential of siRNA.

Purpose of the Study:

• To develop and characterize novel solid nano-in-nanoparticles, termed double nano carriers (DNCs), for enhanced siRNA delivery.
• To evaluate the controlled release, cellular uptake, and therapeutic efficacy of siRNA encapsulated within DNCs.

Main Methods:

• Utilized nano spray drying technology at low temperatures (50°C) to produce DNCs encapsulating siRNA-loaded human serum albumin primary nanoparticles (PNPs) within a Poly (d,l-lactide-co-glycolide) shell.
• Investigated siRNA release profiles from pegylated and non-pegylated DNCs under in vitro conditions.
• Assessed the cytotoxicity and cellular internalization of DNCs in A549 epithelial cell cultures using laser confocal microscopy.
• Confirmed the structural integrity and RNA interference (RNAi) activity of encapsulated siRNA using HPLC, gel electrophoresis, and functional assays.

Main Results:

• Successfully produced DNCs (580-770nm) with a unique inner morphology and smooth spherical surfaces.
• Demonstrated controlled siRNA release from DNCs for up to 12h (non-pegylated) and 24h (pegylated) with minimal burst effect.
• Observed no apparent cytotoxicity of pegylated DNCs in A549 cells and confirmed slow degradation and progressive siRNA release over 6 days.
• Verified the preservation of siRNA structural integrity and potent RNAi activity after encapsulation and release from DNCs.

Conclusions:

• Double nano carriers (DNCs) produced via nano spray drying represent a promising platform for the systemic delivery of siRNA.
• DNCs facilitate controlled release of siRNA, enhance cellular uptake, and maintain the therapeutic activity of the payload.
• This innovative nano drug delivery system holds potential for treating genetic disorders and delivering other sensitive biomacromolecules.