scFv-Transferrin Fusion With Cleavable Linker for Barrier Transport

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Solution Overview

Problem

Many antibodies face challenges in crossing biological barriers such as the blood-brain barrier and blood-eye barrier, and entering cancerous cells due to their size and lack of transcytosis, limiting their efficacy and application in certain diseases.

Innovation Solution

A single-chain variable fragment (scFv) is designed to bind with the N-methyl lobe of transferrin, utilizing transferrin receptor-mediated endocytosis to enhance cellular uptake, and incorporating cleavable linkers that respond to specific cellular environments for targeted and controlled release of therapeutic agents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a full-length antibody is used to maintain stability and effector functions, then therapeutic efficacy is improved, but the ability to cross biological barriers such as the blood-brain barrier and blood-eye barrier is reduced

Engineering Contradiction:

Improvetherapeutic efficacyVSAvoidmolecular size

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The antibody is segmented into its functional components: the scFv region retains antigen-binding capability while the Fc region is removed. This segmentation allows the antigen-binding fragment to cross biological barriers more easily while maintaining therapeutic activity through the preserved variable regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The Fc region is extracted from the full-length antibody structure. This extraction removes the portion responsible for immune effector functions and size-related barrier penetration issues, while the remaining scFv retains the essential antigen-binding function needed for therapeutic efficacy.

Inventive Principle:

Principle #2Taking out (Extraction)

2Length of moving object

If an scFv is used to improve barrier crossing ability, then delivery to target tissues is enhanced, but circulation time and stability are reduced

Engineering Contradiction:

Improvemolecular sizeVSAvoidcirculation time

Core Design Contradiction:

Length of moving objectVSDuration of action of moving object

Solution Approach 1:

Transferrin serves as an intermediary molecule that binds to the scFv through a cleavable linker. This intermediary relationship allows the scFv to utilize transferrin's long circulation time and barrier-crossing capabilities while maintaining its antigen-binding function. The cleavable linker ensures the scFv is released at the target site.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If a fusion protein with transferrin is created to enhance transcytosis, then delivery across biological barriers is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvetranscytosis capabilityVSAvoidprotein structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The fusion protein combines scFv and transferrin into a single composite molecule with a defined structure (scFv-transferrin). This composite structure integrates the barrier-crossing capability of transferrin with the antigen-binding function of scFv, creating a unified therapeutic agent that can be manufactured as a single recombinant protein.

Inventive Principle:

Principle #40Composite materials

4Adaptability or versatility

If cleavable linkers are incorporated for targeted release, then selectivity is improved, but protein stability during circulation is reduced

Engineering Contradiction:

Improvetargeted release capabilityVSAvoidfusion protein stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The cleavable linker is designed to respond to specific parameter changes in the target microenvironment (such as pH changes, enzymatic conditions, or redox state). The linker remains stable under circulation conditions but undergoes controlled cleavage when exposed to the specific parameters present at the disease site, enabling targeted release while maintaining circulation stability.

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

The scFv-conjugate achieves enhanced delivery across biological barriers, reduces off-target effects, and prolongs circulation time, improving therapeutic efficacy and selectivity by ensuring release only in target cells.

Implementation Method 1

utilizing transferrin receptor-mediated endocytosis to enhance cellular uptake

Methodology Applied

Scientific EffectTransferrin receptor-mediated endocytosis:

Implementation Method 2

incorporating cleavable linkers that respond to specific cellular environments for targeted and controlled release of therapeutic agents

Methodology Applied

Scientific EffectEnvironment-responsive cleavage:

Data Source

PatentUS20260042852A1Single-chain dupilumab antibody-transferrin fusion protein for enhanced efficacy and indications

Publication Date: 2026.02.12 RNA THERAPEUTICS INC

AI summary

The efficacy and indication of dupilumab do not depend on the Fc region and are subject to transit across cell walls. They can be expanded by using their scFvs conjugated with N-methyl lobe of transferrin protein connected with an environment-sensitive cleavable linker to prevent exocytosis of the scFv yielding high exposure inside body cells such as in the brain, eye, and cancer cells that overexpress transferrin receptors.