Plasma-Activated Gas Sterilization for Thermolabile Items
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sterilization methods, such as autoclaving, ethylene oxide, hydrogen peroxide, and plasma sterilization, face challenges with thermally labile items, limited penetration into complex structures, and the handling of toxic substances, leading to inefficient and costly processes.
Innovation Solution
A method using a plasma-activated gas mixture generated from air, with NO2 concentrations above 0.3%, is created by spatially separating the ionization and cooling phases, allowing for efficient and rapid sterilization of items, including those with narrow gaps, without direct plasma contact and using only ambient air and water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If autoclaving (moist heat) is used for sterilization, then sterilization effect is very good, but thermally labile items cannot be sterilized
Solution Approach 1:
The invention changes the physical and chemical parameters of the sterilization process by using plasma-activated gas mixtures instead of high-temperature steam. The plasma activation creates reactive species (NO, NO2, O3, radicals) that achieve sterilization through chemical oxidation and DNA damage rather than thermal effects, enabling sterilization of thermally labile items while maintaining high reliability
Solution Approach 2:
The invention replaces the mechanical thermal sterilization system (autoclave with steam and heat) with a plasma-based chemical sterilization system. The plasma source generates activated gas mixtures that deliver sterilizing agents directly, substituting the mechanical heat transfer mechanism with a chemical reaction-based mechanism that is gentler on sensitive materials
2Adaptability or versatility
If ethylene oxide (ETO) is used for sterilization of thermally labile materials, then sterilization is achieved, but outgassing times are very long (several times longer than treatment time)
Solution Approach 1:
The invention uses short-lived reactive plasma species (radicals, excited molecules) that decay rapidly after sterilization instead of persistent chemical residues like ETO. These plasma-generated species (NO, NO2, O3) naturally decompose to harmless components (N2, O2) within seconds to minutes, eliminating long outgassing periods and enabling rapid turnover of sterilized items
Solution Approach 2:
The invention changes the temporal parameters of the sterilization process by using plasma activation that achieves sterilization in seconds to minutes rather than hours. The plasma process creates immediate sterilizing effects through reactive species generation, and the absence of persistent chemical residues eliminates the extended outgassing phase required by ETO sterilization
3Adaptability or versatility
If hydrogen peroxide sterilization is used, then sterilization of thermally labile items is possible, but condensation in narrow gaps must be avoided and evaporation is irregular and long-lasting
Solution Approach 1:
The invention uses plasma-activated gas mixtures (pneumatic approach) instead of liquid hydrogen peroxide. The activated gas flows uniformly through and around items, penetrating narrow gaps and lumens without condensation issues. The gaseous state ensures consistent distribution and eliminates the liquid handling problems associated with hydrogen peroxide sterilization
Solution Approach 2:
The invention avoids the liquid-to-vapor phase transition problems of hydrogen peroxide by using plasma-generated reactive species in the gas phase. The plasma activation process creates sterilizing radicals and excited molecules that remain in the gas phase throughout the sterilization process, eliminating condensation and evaporation issues that plague liquid-based systems
4Reliability
If ionizing radiation is used for sterilization, then sterilization is achieved, but equipment requirements are major and material damage may occur
Solution Approach 1:
The invention replaces complex ionizing radiation equipment (accelerators, gamma sources) with a plasma-based system that uses electromagnetic fields to generate plasma. The plasma source uses simpler components (power supply, gas flow control, plasma generation chamber) to create reactive species that achieve sterilization through chemical oxidation rather than ionizing radiation, reducing equipment complexity while maintaining effectiveness
Solution Approach 2:
The invention changes the energy parameters of the sterilization process by using non-ionizing plasma energies that are sufficient to create reactive species but too low to cause material damage. The plasma process operates at lower energy levels than ionizing radiation, using electron impact and photon excitation to generate radicals without the penetrating damage associated with high-energy radiation
5Adaptability or versatility
If plasma sterilization under vacuum is used, then sterilization of heat-sensitive items is possible, but penetration into narrow gaps and lumens is not very good
Solution Approach 1:
The invention uses plasma-activated gas mixtures that can be delivered at atmospheric or elevated pressures, providing strong driving force for penetration into narrow gaps and lumens. The gas flow dynamics enable deep penetration into complex structures, overcoming the limitation of vacuum plasma where gas flow is restricted. The pneumatic delivery system ensures uniform distribution of reactive species throughout complex geometries
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 achieves rapid and effective sterilization of items in seconds, reducing material damage and operational costs, while minimizing the use of hazardous substances and ensuring safety, making it suitable for mass-produced medical products and packaging.
Implementation Method 1
generating a plasma, preferably from air as process gas, which forms reactive nitrogen and oxygen species
Implementation Method 2
a) generating a plasma, preferably from air as process gas, which forms reactive nitrogen and oxygen species
Implementation Method 3
b) cooling the plasma gas in a cooling device, so that the plasma gas is converted into a plasma-activated gas mixture
Implementation Method 4
b) oxidizing NO to NO2, at temperatures below 400° C., so that a plasma-activated gas mixture with an NO2 content of at least 0.3% is formed
Data Source
AI summary
The invention relates to a method and to a device for quickly decontaminating and sterilizing preferably thermolabile goods using a plasma gas that is preferably generated from air as a process gas, with the subsequent humidification of said plasma gas with water. The method comprises the following steps: generating a plasma from air as the process gas, which forms reactive nitrogen and oxygen species; oxidizing NO to form NO2 at temperatures below 400° C. so that a plasma-activated gas mixture forms having an NO2 content of at least 0.3%; bringing said plasma-activated gas mixture in contact with water in one or more of the states of aggregation thereof; bringing the latter gas mixture in contact with the objects to be decontaminated or sterilized.