Modified Silk Fibroin Composition for Stable Aqueous Solubility
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Solution Overview
Problem
Silk fibroin proteins in aqueous solutions are prone to aggregation and gelation due to beta-sheet formation, leading to instability and limited shelf-life, which current methods to prevent aggregation either result in dilute solutions or introduce toxic chemicals.
Innovation Solution
A process involving heating silk fibroin solutions at elevated pressures and temperatures with high lithium bromide concentrations to modify the primary amino acid sequence, reducing cysteine disulfide bonds and serine content, resulting in a fibroin-derived protein composition with enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional methods (detergent extraction, high-heat washing) are used to remove sericin, then fibroin fibers are obtained, but the fibroin becomes water-insoluble and requires high salt concentrations for dissolution
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of fibroin through controlled hydrolysis to alter its solubility properties. The process transforms native fibroin into a modified form that maintains high protein content while achieving water solubility without requiring high salt concentrations, thus resolving the contradiction between protein quantity and ease of dissolution.
2Quantity of substance
If high salt concentrations are used to solubilize fibroin, then water-soluble protein solution is obtained, but the solution becomes unstable and prone to aggregation and gelation
Solution Approach 1:
The patent modifies the protein's chemical parameters through hydrolysis to change its interaction properties with water and other molecules. This transformation reduces the protein's tendency to aggregate and form gels, thereby improving solution stability while maintaining high protein concentration, thus resolving the contradiction between protein quantity and solution stability.
Solution Approach 2:
The patent extracts and removes harmful components (disulfide bonds, specific amino acid sequences) from the fibroin structure through controlled hydrolysis. By taking out these problematic elements, the solution becomes more stable and less prone to aggregation, resolving the contradiction between high protein content and solution stability.
3Stability of the object's composition
If fibroin concentration is lowered to reduce aggregation, then protein-protein interactions are minimized, but the solution becomes too dilute for relevant applications
Solution Approach 1:
The patent changes the intrinsic parameters of the protein through hydrolysis to reduce its aggregation propensity. This allows the protein to remain stable at high concentrations without requiring dilution, thus resolving the contradiction between aggregation resistance and protein concentration by modifying the protein's fundamental properties rather than adjusting concentration.
4Stability of the object's composition
If chemical modifications are applied to prevent aggregation, then solution stability is improved, but biological toxicity or incompatible agents are introduced
Solution Approach 1:
The patent extracts harmful elements from the fibroin structure through controlled hydrolysis, specifically removing disulfide bonds and modifying amino acid sequences that cause aggregation. This extraction approach improves stability without introducing external chemical agents, thus resolving the contradiction between shelf-life stability and biological toxicity by eliminating problems from within the protein itself rather than adding external substances.
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 modified fibroin-derived protein composition maintains stability in aqueous solutions, preventing aggregation and gelation, allowing for high-concentration solutions with extended shelf-life suitable for various applications.
Implementation Method 1
heating an aqueous fibroin solution at an elevated pressure. The aqueous fibroin solution is heated to at least about 105° C. (221° F.) under a pressure of at least about 10 PSI for at least about 20 minutes
Implementation Method 2
Conversion of these fibrils into water-soluble silk fibroin protein requires the addition of a concentrated heavy salt (e.g., 8-10M lithium bromide), which interferes with inter- and intra-molecular ionic and hydrogen bonding that would otherwise render the fibroin protein water-insoluble
Implementation Method 3
Conversion of these fibrils into water-soluble silk fibroin protein requires the addition of a concentrated heavy salt (e.g., 8-10M lithium bromide), which interferes with inter- and intra-molecular ionic and hydrogen bonding that would otherwise render the fibroin protein water-insoluble
Implementation Method 4
The aggregation is thought to occur through interactions between fibroin proteins, and then subsequent material gelation driven through beta-sheet secondary protein structure formation between the hydrophobic amino acid motifs of the fibroin heavy chains
Data Source
AI summary
A protein composition derived from silk fibroin, which composition possesses enhanced solubility and stability in aqueous solutions. The primary amino acid sequence of native fibroin is modified in the SDP such that cysteine disulfide bonds between the fibroin heavy and fibroin light protein chains are reduced or eliminated. Additionally, the composition can have a serine content that is reduced by greater than 40% compared to native fibroin protein, and the average molecular weight of the SDP is less than about 100 kDa.