Liposomal Nucleic Acid Particles for Stable Sub-50 Nm Delivery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liposomal particles, particularly small unilamellar vesicles (SUVs), face challenges of instability and aggregation leading to inter-particle fusion, limiting their therapeutic use due to size limitations and inefficient surface density modification techniques.
Innovation Solution
The use of tocopherol-modified oligonucleotides with a lipophilic end and a non-lipophilic end, such as RNA or DNA, anchored into the lipid bilayer to create stable liposomal particles with a dense layer, enhancing stability and surface density, allowing for sizes below 50 nanometers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If small unilamellar vesicles (SUVs) are used to achieve small particle size, then particle size is reduced, but stability deteriorates due to aggregation and inter-particle fusion
Solution Approach 1:
The invention segments the modification process into two distinct stages: first forming the liposomal vesicles, then separately attaching the oligonucleotide-lipid conjugates to the vesicle surface. This segmentation allows optimization of each stage independently, enabling small particle size while maintaining stability through controlled surface modification.
Solution Approach 2:
The invention performs preliminary action by pre-modifying oligonucleotides with lipophilic anchors (such as cholesterol or tocopherol groups) before vesicle formation. This preliminary modification ensures that the oligonucleotides are ready for efficient attachment to the liposomal surface, achieving high surface density without compromising vesicle stability during the size-reduction process.
2Quantity of substance
If post modification technique with cholesterol anchors is used to attach oligonucleotides, then oligonucleotide attachment is achieved, but surface density is limited due to use of two cholesterol molecules per oligonucleotide
Solution Approach 1:
The invention changes the key parameter of the lipophilic anchor structure by using single-molecule anchors (such as tocopherol derivatives or cholesterol monomers) instead of traditional dual-cholesterol anchors. This parameter change reduces the molecular complexity while achieving equivalent or superior anchoring efficiency, thereby increasing the surface density of oligonucleotides on the liposomal particles.
3Stability of the object's composition
If non-post modification technique with nucleotide segments hybridized is used, then vesicle formation is achieved, but stability is reduced due to incorporatio of stabilizing moieties on both sides of the lipid bilayer
Solution Approach 1:
The invention extracts the stabilizing function from the oligonucleotide sequence itself and places it solely on the lipid anchor portion that embeds in the bilayer. By taking out the stabilizing moieties from both-sided incorporation and concentrating them in the lipophilic anchor, the technique simplifies the manufacturing process while maintaining or enhancing vesicle stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The tocopherol-modified liposomal particles exhibit increased stability, improved colloidal stability, enhanced cellular uptake, and effective gene regulation capabilities without toxic effects, facilitating efficient gene knockdown and bio-distribution.
Implementation Method 1
a lipophilic end and a non-lipophilic end... anchored into the lipid bilayer
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
Liposomes termed as small unilamellar vesicles (SUVs), can be synthesized in the 20-50 nm size range, but encounter challenges such as instability and aggregation leading to inter-particle fusion. This limits their use as a therapeutic delivery agent. Increasing the surface negative charge of SUVs, via the attachment of anionic entities such as DNA/RNA, increases the colloidal stability of these vesicles. Additionally, the dense spherical arrangement and radial orientation of nucleic acids exhibits unique chemical and biological properties, unlike their linear counterparts. These liposomal particles, are non-toxic and though anionic, can efficiently enter cells without the aid of ancillary cationic transfection agents in a non-immunogenic fashion. These exceptional properties allow their use as delivery agents for gene regulation in different therapies and offer an alternative platform to metal core spherical nucleic acids.