Branched Polypeptide Carriers for Stable, Low-Toxicity Nucleic Acid Delivery

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Solution Overview

Problem

Current nucleic acid delivery systems face challenges such as degradation, precipitation, low cellular uptake, and poor endosomal escape, leading to inefficient gene delivery and potential cytotoxicity, especially in vivo.

Innovation Solution

A branched structure polypeptide carrier with specific amino acid sequences and disulfide bonds is developed, forming stable nanostructures through electrostatic interactions with nucleic acids, enhancing delivery efficiency and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cationic polymers like poly-L-lysine, DEAE-dextran, polyethyleneimine (PEI), and chitosan are used to deliver nucleic acids, then nucleic acid protection and cellular internalization are improved, but cytotoxicity increases and nucleic acid expression efficiency decreases

Engineering Contradiction:
Improvenucleic acid protectionVSAvoidcytotoxicity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical parameters of the carrier by using a branched polypeptide structure with specific amino acid sequences and disulfide bonds, altering the physical and chemical properties to reduce cytotoxicity while maintaining nucleic acid protection and delivery efficiency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite system by combining the branched polypeptide carrier with nucleic acids through electrostatic interactions, forming a stable nanocomplex that protects the nucleic acid while enabling cellular uptake and reducing toxicity

Inventive Principle:
Principle #40Composite materials

2Reliability

If small-molecule cationic lipids like DOTAP and DDAB are used for nucleic acid delivery, then electrostatic binding and protection are achieved, but transfection efficiency in vivo is insufficient

Engineering Contradiction:
Improvenucleic acid protectionVSAvoidtransfection efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention segments the carrier structure into a branched polypeptide with multiple arms, each capable of interacting with nucleic acids and cell membranes, improving transfection efficiency through increased surface area and multiple interaction sites

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the molecular weight, charge density, and structural conformation parameters by using a branched polypeptide instead of small-molecule lipids, enabling improved in vivo transfection efficiency while maintaining protection capabilities

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If linear peptides are used as carriers, then simplicity of structure is maintained, but stability and delivery efficiency are reduced

Engineering Contradiction:
Improvestructure simplicityVSAvoidstability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention segments the peptide structure into multiple branched arms connected to a central core, creating a three-dimensional architecture that increases stability and delivery efficiency while maintaining defined chemical structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a one-dimensional linear peptide structure to a three-dimensional branched structure, adding spatial dimensions that enhance stability, protection capacity, and cellular interaction efficiency

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Device complexity

If nucleic acids are delivered without a carrier, then simplicity of administration is maintained, but degradation, precipitation, and low cellular uptake occur

Engineering Contradiction:
Improveadministration simplicityVSAvoidnucleic acid stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention introduces a branched polypeptide as an intermediary carrier that mediates between the nucleic acid and the cellular environment, protecting the nucleic acid from degradation and precipitation while facilitating cellular uptake through electrostatic interactions and endosomal escape

Inventive Principle:
Principle #24Intermediary (Mediator)

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 branched polypeptide carrier achieves high gene delivery efficiency, long-term stability, and minimal toxicity, effectively delivering nucleic acids to tissues and organs for targeted therapy.

Implementation Method 1

Nucleic acids typically exhibit a negative charge under physiological conditions. Cationic compounds can electrostatically bind with nucleic acids, compressing and protecting them from enzymatic degradation.

Methodology Applied
Scientific EffectElectrostatic interaction: Electrostatics

Implementation Method 2

These compounds facilitate fusion with cell membranes, enabling nucleic acids to escape from endosomes.

Methodology Applied
Scientific EffectElectrostatic interaction: Electrostatics

Implementation Method 3

By leveraging non-covalent interactions (e.g., hydrophobic interactions, electrostatic interactions, hydrogen bonding, and π-π stacking), polypeptides can self-assemble into stable nanostructures.

Methodology Applied
Scientific EffectHydrophobic interaction: Hydrophobe

Implementation Method 4

By leveraging non-covalent interactions (e.g., hydrophobic interactions, electrostatic interactions, hydrogen bonding, and π-π stacking), polypeptides can self-assemble into stable nanostructures.

Methodology Applied
Scientific EffectHydrogen bonding: Chemical Bonding

Implementation Method 5

Advancements in solid-phase synthesis enable the production of high-purity polypeptides with defined structures and biologically active secondary configurations, such as α-helices and β-sheets.

Methodology Applied
Scientific EffectDisulfide bond: Chemical Bonding

Data Source

PatentEP4578869A1Branched polypeptide vector for effectively delivering nucleic acids and variant thereof
Publication Date: 2025.07.02 SUZHOU HEALIRNA BIOTECHNOLOGY CO LTD
  • EP4578869A1 patent drawingFigure 1
  • EP4578869A1 patent drawingFigure 2
  • EP4578869A1 patent drawingFigure 3

AI summary

The present invention provides a branched structure peptide carrier and its variations, wherein the branched structure peptide has the following sequence formula: 1. Xaa1(P2)-Xaa1-Xaa1(P1)-Xaa1-Xaa1(P2) 2. Xaa1(P1)-Xaa1-Xaa1(P2)-Xaa1-Xaa1(P2)-Xaa1-Xaa1(P1) 3. Xaa1(P2)-Xaa1-Xaa1(P1)-Xaa1-Xaa1(P1)-Xaa1-Xaa1(P2) 4. Xaa1(P2)-Xaa1-Xaa1(P1)-Xaa1-Xaa1(P2)-Xaa1-Xaa1(P1)-Xaa1-Xaa1( P2) The technical solution of the present invention enables efficient delivery of nucleic acids to tissues and organs in vivo for targeted therapy. The peptides have several times more conformational flexibility and affinity compared to macromolecular drugs (proteins and antibodies). The branched peptides possess long-lasting in vivo stability while maintaining strong affinity and minimal toxicity. By forming stable nanocomplexes or nanoparticles through electrostatic interactions with nucleic acid molecules, they can facilitate the delivery of nucleic acid drugs and their stable release inside cells, thereby enhancing the activity of nucleic acid-based therapeutics.