Supercritical CO2 Sterilization of Demineralized Bone Matrix
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Solution Overview
Problem
Current sterilization methods for tissues, such as gamma-irradiation and ethylene oxide, alter the structure of biomaterials and can reduce osteoinductivity of demineralized bone matrix, while ethylene oxide is a carcinogen and can cause toxic reactions.
Innovation Solution
Supercritical carbon dioxide (SC-CO2) is used as a sterilant, combined with peracetic acid, to sterilize demineralized bone matrix, maintaining its osteoinductivity and allowing storage at ambient conditions for extended periods without significant degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gamma-irradiation or e-beam sterilization is used, then sterilization effectiveness is improved, but osteoinductivity of demineralized bone matrix is reduced or eliminated
Solution Approach 1:
The patent changes the sterilization parameters by using supercritical carbon dioxide (temperature: 31°C to 50°C, pressure: 73 atm to 300 atm) instead of gamma-irradiation or e-beam, maintaining osteoinductivity while achieving sterilization
Solution Approach 2:
The patent introduces supercritical carbon dioxide as an intermediary sterilizing agent that can penetrate the bone matrix and kill microorganisms without causing the crosslinking or degradation that directly affects osteoinductivity
2Reliability
If ethylene oxide sterilization is used, then sterilization effectiveness is improved, but toxic residues remain causing hemolysis and other toxic reactions
Solution Approach 1:
The patent uses supercritical carbon dioxide which, like a disposable solution, completely evaporates after sterilization leaving no toxic residues, unlike ethylene oxide which leaves persistent toxic residues
Solution Approach 2:
The patent converts the potential harm of high pressure and temperature in supercritical state into a beneficial sterilization process that eliminates microorganisms without leaving toxic residues
3Reliability
If ethylene oxide sterilization is used, then sterilization effectiveness is improved, but collagen matrix structure is altered through degradation
Solution Approach 1:
The patent changes the sterilization parameters to supercritical carbon dioxide conditions (31°C to 50°C, 73 atm to 300 atm) which are gentler on the collagen matrix compared to ethylene oxide, preserving the triple-helix structure and amino acid composition
4Reliability
If conventional sterilization methods are used, then sterilization is achieved, but storage stability over extended periods is reduced
Solution Approach 1:
The patent performs preliminary sterilization with supercritical carbon dioxide that completely eliminates microorganisms and stabilizes the bone matrix, enabling long-term storage stability for at least 12 months at ambient conditions without further degradation
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 method effectively sterilizes demineralized bone matrix while preserving its osteoinductive properties, achieving a high Sterility Assurance Level and ensuring safety without toxic residues, as demonstrated by successful bone formation in rat implantation studies.
Implementation Method 1
treating a demineralized bone matrix in a supercritical carbon dioxide (SC—CO2) chamber with a sterilant
Data Source
AI summary
Systems and methods for sterilization of tissue are provided.