Cis-Double-Bond Ionizable Lipids for High-Encapsulation RNA Nanoparticles
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Solution Overview
Problem
Existing ionizable lipid compounds face challenges in delivering nucleic acids efficiently due to low delivery efficiency, which hinders their application in therapeutic settings.
Innovation Solution
A novel ionizable lipid compound with a specific structure, capable of forming lipid nanoparticles, is developed to enhance delivery efficiency by encapsulating bioactive substances like mRNA, siRNA, and other nucleic acids, utilizing a synthesis method that includes reacting amines with epoxy-terminated compounds to form tertiary amines, and combining with other lipids to create uniform nanoparticles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing ionizable lipid compounds are used to deliver nucleic acids, then the delivery system can be formed, but the delivery efficiency remains low
Solution Approach 1:
The patent modifies the chemical structure of ionizable lipid compounds by introducing specific substituents (aromatic rings, heteroatoms, different chain lengths) to optimize properties such as pKa, encapsulation efficiency, and cellular uptake. These parameter changes in molecular structure directly improve delivery efficiency while maintaining the fundamental LNP formation capability
Solution Approach 2:
The patent develops novel ionizable lipid compounds that combine multiple functional groups (ionizable amino groups, hydrophobic tails, aromatic rings) within a single molecular structure. This composite approach creates lipids with enhanced ability to interact with nucleic acids, form stable LNPs, and facilitate cellular entry, thereby resolving the low delivery efficiency issue
2Productivity
If mRNA is delivered without adequate protection, then it can potentially reach target cells, but it is degraded by nucleases quickly
Solution Approach 1:
The patent utilizes lipid nanoparticles formed by ionizable lipid compounds to create a protective shell around mRNA. This flexible lipid membrane encapsulates the nucleic acid, physically shielding it from nuclease degradation in the extracellular environment while allowing cellular uptake and subsequent release inside target cells
Solution Approach 2:
The ionizable lipid compound acts as an intermediary between the unstable mRNA and the hostile biological environment. The lipid forms a protective complex with mRNA through electrostatic interactions, mediating protection during circulation and facilitating controlled release at the target site, thereby extending mRNA stability without compromising delivery effectiveness
3Productivity
If mRNA is used for therapy, then it can achieve protein expression without genetic mutation risk, but it carries large negative charges making it difficult to cross cell membranes
Solution Approach 1:
The patent exploits the pH-dependent ionization property of the lipid compounds, which are neutral at physiological pH but become positively charged in the acidic endosomal environment. This inversion of charge state allows the LNP to remain stable in circulation, then spontaneously fuse with or be taken up by cells through electrostatic attraction in the acidic endosome, overcoming the negative charge barrier of both mRNA and cell membranes
Solution Approach 2:
The patent optimizes the pKa of the ionizable lipid compounds to ensure they remain predominantly uncharged at blood pH (minimizing non-specific interactions) but become protonated and positively charged at endosomal pH (facilitating membrane interaction and uptake). This parameter optimization resolves the contradiction between maintaining stability during circulation and achieving efficient cellular entry
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 novel lipid compound achieves high encapsulation efficiency and cell transfection efficiency, with nanoparticles having uniform sizes and improved stability, effectively delivering therapeutic agents to cells.
Implementation Method 1
An amino group of the ionizable lipid compound can be protonated to form a positively charged headgroup under suitable acidic conditions
Implementation Method 2
the tail of which is composed of a hydrophobic carbon chain. The charged moiety is used to electrostatically bind to negatively charged RNA, while the hydrophobic tail enables it to self-assemble into a lipophilic particle
Implementation Method 3
Lipid nanoparticles (LNPs) formed by self-assembly of the ionizable lipid compounds in combination with other three or four lipids such as distearoyl phosphatidylcholine (DSPC) or dioleoyl-phosphatidylethanolamine (DOPE), cholesterol (CHOL), and PEGylated lipids are used to deliver nucleic acids, can protect the nucleic acids from degradation by nucleases
Data Source
AI summary
Provided are an ionizable lipid compound with an adjacent cis-double bond structure, a preparation method therefor, and the use thereof in the delivery of an active therapeutic agent (e.g., a nucleic acid). The ionizable lipid compound can provide a higher encapsulation rate of active substances and a better cell or in vivo transfection rate, and is particularly suitable for preparing nanoparticles with a solid structure.