Anionic Shielding Polymer Complexes for Stable Non-Viral Delivery
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Solution Overview
Problem
Existing cationic polymer-based non-viral vectors face challenges such as high cytotoxicity, aggregation, and reduced transfection efficiency due to the use of polyethylene glycol (PEG) shielding, which also induces immune responses and reduces cellular uptake.
Innovation Solution
Development of polymer complexes comprising a cationic polymer covalently or electrostatically bonded with active ingredients and a shielding component made of an anionic copolymer containing methionine sulfoxide-based blocks, which provides low cytotoxicity, enhanced permeability and retention, and stability in the bloodstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If polyethylene glycol (PEG) is used as shielding component on cationic polymer-based non-viral vectors, then stability in bloodstream and avoidance of aggregation are improved, but cellular uptake efficiency and transfection efficiency deteriorate due to neutral surface charge and steric hindrance
Solution Approach 1:
The patent changes the charge parameter of the shielding component from neutral (PEG) to anionic, which fundamentally alters the surface properties. This enables the shielding layer to maintain stability and prevent aggregation while preserving cellular uptake efficiency through electrostatic interactions with cell membranes.
Solution Approach 2:
The anionic copolymer acts as an intermediary between the cationic polymer core and the cellular environment. It provides steric protection and stability in bloodstream while its negative charge facilitates interaction with cell surfaces, mediating both protection and uptake functions.
2Duration of action of moving object
If polyethylene glycol (PEG) is used as shielding component, then circulation time is prolonged, but immune response and cytotoxicity increase due to anti-PEG antibody formation
Solution Approach 1:
The patent replaces PEG with naturally occurring anionic copolymers (hyaluronic acid, chondroitin sulfate, heparin) that are biocompatible and rapidly cleared if needed, avoiding the persistent immunogenicity of PEG. These natural polymers provide temporary shielding without long-term immune sensitization.
Solution Approach 2:
The patent changes the chemical identity parameter of the shielding component from synthetic PEG to natural anionic copolymers, fundamentally altering the immunogenicity profile while maintaining the protective function and prolonging circulation time.
3Ease of operation
If cationic polymer has high amine density and appropriate pKa, then endosomal membrane barrier penetration is improved, but aggregation in bloodstream and non-specific interaction with serum components worsen
Solution Approach 1:
The patent divides the polymeric vector into two distinct functional segments: a cationic polymer core responsible for endosomal penetration and an anionic copolymer shell responsible for bloodstream stability. This segmentation allows each segment to optimize its function without compromising the other.
Solution Approach 2:
The patent applies different charge properties to different parts of the vector system: the core maintains positive charge for endosomal interaction while the surface shell carries negative charge for bloodstream circulation. This local differentiation of charge quality resolves the contradiction between penetration and 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 polymer complexes achieve high solubility, stability, and efficient delivery of active ingredients to cells with reduced aggregation and immune response, while maintaining adequate plasma half-life and cellular uptake.
Implementation Method 1
the polyion complex (PIC) specifically formed by electrostatic interaction between a nucleic acid acting as a polyanion and a cationic polymer
Implementation Method 2
the nucleic acid is condensed as a result of the interaction of the nucleic acid with the polycation portion in the block copolymer to form a core portion
Data Source
Figure 1A~1B
Figure 2
AI summary
The present invention relates to new polymer complexes comprising at least one anionic poly(methionine sulfoxide)-based copolymer, which are useful as non-viral vectors for delivery of active ingredients, including nucleic acids, to cells.