Resorbable Oxidized Cellulose Microspheres Dissolution
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Solution Overview
Problem
Current cellulose dissolution processes are cumbersome, expensive, and often require harsh conditions, leading to degradation and limited solubility in common solvents, which hinders the full exploitation of cellulose's potential in various industries.
Innovation Solution
A method using a polar aprotic solvent and a salt added in a step-wise manner to dissolve oxidized or non-modified cellulose, minimizing degradation by conducting the process in an inert atmosphere with controlled temperature and shearing forces, allowing for the formation of stable cellulose microspheres for medical applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional cellulose dissolution processes (cuprammonium, xanthate) are used, then cellulose can be dissolved, but the processes are cumbersome, expensive, and require harsh conditions leading to degradation
Solution Approach 1:
The patent changes the chemical parameters of the dissolution system by using lithium hydroxide and carbon dioxide to create a milder alkaline environment (pH 8-10), replacing the harsh traditional solvents. This parameter change enables cellulose dissolution without degradation while simplifying the process
Solution Approach 2:
The patent creates a controlled inert environment by conducting dissolution in an atmosphere saturated with carbon dioxide, which stabilizes the alkaline conditions and prevents unwanted side reactions. This inert environment protection maintains cellulose integrity during dissolution
2Reliability
If traditional cellulose dissolution processes are used, then cellulose can be dissolved, but excessive physical manipulation and lengthy treatment periods cause degradation and removal of oxidized groups
Solution Approach 1:
The patent optimizes treatment time parameters by limiting dissolution to 0.5-4 hours and maintaining temperature at 20-50°C, preventing excessive treatment that would remove oxidized groups. The controlled time parameter preserves oxidation state while achieving dissolution
Solution Approach 2:
The patent reduces mechanical stress by minimizing physical manipulation during dissolution, replacing vigorous stirring with gentler mixing methods. This substitution preserves the oxidized groups on cellulose chains that would otherwise be removed by excessive mechanical treatment
3Reliability
If cellulose is dissolved under harsh conditions, then dissolution can be achieved, but molecular weight and degree of oxidation are compromised
Solution Approach 1:
The patent precisely controls dissolution parameters including pH (8-10), temperature (20-50°C), and time (0.5-4 hours) to achieve complete dissolution while maintaining molecular weight within 90-110% of original values and preserving degree of oxidation
Solution Approach 2:
The patent implements monitoring and control feedback by measuring pH, temperature, and dissolution progress to adjust conditions in real-time, ensuring molecular weight and oxidation state remain within desired ranges throughout the dissolution process
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
This method effectively dissolves cellulose with minimal degradation, enabling the formation of stable microspheres for medical uses such as embolization procedures, while maintaining the molecular weight and degree of oxidation of the cellulose, thus overcoming the limitations of traditional dissolution processes.
Implementation Method 1
dissolving cellulose in an alkaline solution comprising lithium hydroxide and carbon dioxide
Implementation Method 2
The dissolved cellulose may then be contacted with a cross-linking agent, a precipitating agent, or a gelation composition
Data Source
AI summary
A method for forming an embolism within a blood vessel is disclosed. The method includes including: implanting a plurality of oxidized cellulose microspheres into a lumen of a blood vessel to at least partially block the lumen.