Anionic siRNA-TLP Particles for Toxicity-Free Gene Delivery

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Solution Overview

Problem

The systemic delivery of therapeutic siRNA is challenging due to issues like instability, inefficient targeting, exclusion from cell cytosol, toxicity, and high costs associated with chemical modifications and existing delivery vehicles, particularly cationic lipids and polymers.

Innovation Solution

The development of templated lipoprotein particles (TLPs) that self-assemble with short interfering RNA (siRNA), featuring a core, a lipid shell, and an apolipoprotein, which are anionic and actively targeted, allowing for the delivery of unmodified siRNA to cells without toxicity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cationic lipids or polymers are used as delivery vehicles for siRNA, then siRNA stability and cell uptake are improved, but toxicity and serum opsonization increase

Engineering Contradiction:

ImprovesiRNA stabilityVSAvoidtoxicity

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the charge parameter of the delivery vehicle from positive (cationic) to negative (anionic) by using HDL-mimetic particles with anionic phospholipids. This parameter change maintains siRNA stability while eliminating the toxicity and serum opsonization problems associated with cationic vehicles.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite structure combining HDL-mimetic lipoprotein particles with siRNA. The composite consists of an anionic phospholipid bilayer core surrounded by apolipoprotein, creating a biocompatible delivery vehicle that avoids the harmful effects of synthetic cationic materials while maintaining delivery functionality.

Inventive Principle:

Principle #40Composite materials

2Reliability

If chemical modifications are made to siRNA phosphate backbone or ribose sugar, then RNA stability is improved, but cost significantly increases and off-target effects may be generated

Engineering Contradiction:

ImproveRNA stabilityVSAvoidcost

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention introduces an anionic HDL-mimetic delivery vehicle as an intermediary between unmodified siRNA and the cellular environment. This mediator protects the unmodified siRNA from degradation without requiring chemical modifications, thereby maintaining low cost while achieving stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention uses inexpensive, unmodified siRNA instead of costly chemically modified versions. The transient protection provided by the HDL-mimetic vehicle allows the use of simple, cheap siRNA that would otherwise be rapidly degraded, eliminating the need for expensive modifications.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Duration of action of moving object

If cationic delivery vehicles are used, then circulating half-life is improved, but active targeting capability is lost

Engineering Contradiction:

Improvecirculating half-lifeVSAvoidactive targeting

Core Design Contradiction:

Duration of action of moving objectVSAdaptability or versatility

Solution Approach 1:

The HDL-mimetic particle structure serves multiple functions: it provides extended circulating half-life through protein corona formation similar to natural HDL, and simultaneously enables active targeting through the presence of apolipoprotein A-1 that recognizes SR-BI receptors on target cells. This multi-functionality resolves the trade-off between half-life and targeting.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention changes the surface charge parameter from positive to negative, which fundamentally alters the interaction mechanism with serum proteins and cells. The anionic surface enables formation of a protective protein corona that extends half-life, while the apolipoprotein component provides specific receptor-mediated targeting capability.

Inventive Principle:

Principle #35Parameter changes

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

This approach enables potent gene regulation in vitro and in vivo, significantly reducing cancer xenograft growth with no off-target toxicity, and is modular for targeting various protein interests, overcoming the limitations of current siRNA delivery methods.

Implementation Method 1

cellular uptake of the TLP was dependent on the presence of apolipoprotein A-1 and scavenger receptor class B type I (SR-BI)

Methodology Applied

Scientific EffectReceptor-mediated endocytosis:

Implementation Method 2

self-assembling single-stranded highly unmodified RNA complements of an siRNA duplex pair in anionic delivery vehicles

Methodology Applied

Scientific EffectElectrostatic interaction:

Data Source

PatentUS10967072B2Short interfering RNA templated lipoprotein particles (siRNA-TLP)

Publication Date: 2021.04.06 NORTHWESTERN UNIV

AI summary

Nanostructures for the systemic delivery of nucleic acids, such as RNA, are provided herein. The nanostructures include templated lipoprotein nanoparticles (TLPs) composed of a core decorated with proteins, a lipid bilayer and hydrophobic molecules that self-assemble with nucleic acids, such as RNA. The nanostructures are useful for research, therapeutic and diagnostic applications.