Ferritin Variants for Enhanced Drug Encapsulation
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Solution Overview
Problem
Current ferritin drug complexes have not successfully reached clinical use due to limitations in drug encapsulation efficiency, stability, and cytotoxicity against tumor cells, as well as issues with dimer formation and aggregation.
Innovation Solution
Ferritin variants with specific mutations, such as deletion or substitution of lysine residues with non-basic amino acids and cysteine residues, enhance encapsulation efficiency, stability, and cytotoxicity, while reducing dimer formation and aggregation, allowing for improved drug delivery and targeting of cancer cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wild-type ferritin is used as a drug carrier, then it maintains natural biocompatibility, but it shows poor drug encapsulation efficiency and instability
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of ferritin through specific mutations (deletion or substitution of lysine residues at positions 54, 72, 87, and/or 144; deletion or substitution of cysteine residues at positions 91, 103, and/or 131). These parameter changes in the protein structure improve both the stability and drug encapsulation efficiency simultaneously, resolving the technical contradiction between reliability and productivity.
2Stability of the object's composition
If wild-type ferritin is used, then it maintains natural structure, but it forms dimers and aggregates reducing delivery efficiency
Solution Approach 1:
The patent uses parameter changes by introducing specific point mutations in the ferritin sequence that prevent dimer formation while maintaining the functional nanocage structure. The deletion or substitution of specific lysine and cysteine residues changes the intermolecular interaction parameters, stabilizing the monomeric form and improving delivery efficiency.
3Object-affected harmful factors
If ferritin is used for drug delivery, then it provides biocompatibility, but it shows insufficient cytotoxicity against tumor cells
Solution Approach 1:
The patent applies local quality by making specific localized mutations at particular amino acid positions (lysine and cysteine residues) while leaving the rest of the ferritin structure intact. This localized modification approach enhances cytotoxicity against tumor cells through improved drug encapsulation and stability, while maintaining overall biocompatibility of the ferritin nanocage.
Data Source
AI summary
The present invention relates to a ferritin variant polypeptide, wherein at least one lysine residue is deleted or substituted with a non-basic amino acid. The invention further relates to a complex of this polypeptide and a label or drug, and an isolated cellular delivery system comprising the polypeptide or the complex of the invention as well as uses of such system for prophylaxis, therapy, diagnosis or theragnosis, in particular for therapy of cancer or inflammatory diseases.