In today’s increasingly stringent environment for medical device sterilization standards, traditional high-temperature sterilization methods are no longer sufficient to meet the processing requirements for heat-sensitive materials. Low-temperature hydrogen peroxide plasma sterilization technology has emerged as a specialized solution for sterilizing instruments and equipment sensitive to heat and humidity. This technology utilizes hydrogen peroxide as a sterilant at low temperatures, combined with a plasma discharge process, to effectively eliminate bacteria, viruses, and spores. However, this method has some drawbacks, such as a lengthy sterilization cycle and high costs. Let’s take a closer look at the working principle, applications, and advantages and disadvantages of the H₂O₂ low temperature plasma sterilizer.

The Working Principle of Hydrogen Peroxide Plasma Sterilizers

A hydrogen peroxide sterilizer is a device that applies H₂O₂ vapor to potentially contaminated surfaces. In principle, hydrogen peroxide can also be used in liquid form for surface disinfection, but it must be diluted in such cases. It is typically used by medical institutions or other facilities with high hygiene standards. Hydrogen peroxide vapor can be used to disinfect a wide range of items, from entire rooms to medical devices such as surgical knives and endoscopes. Smaller items are typically placed in specialized containers and then treated with hydrogen peroxide vapor. After treatment, the number of bacteria on the surface of the items is significantly reduced, and the vapor is expelled from the container. Hydrogen peroxide destroys bacteria and viruses through an oxidation reaction, thereby killing them. This process does not leave behind harmful substances, producing only water and oxygen, making it very safe.

  1. Pre-treatment stage
    The sterilizer is evacuated to reduce the chamber pressure, remove air, and create a suitable environment for subsequent steps.
  2. Injection of hydrogen peroxide vapor
    A solution of hydrogen peroxide at a certain concentration is injected into the sterilization chamber in the form of mist or vapor, ensuring it is evenly distributed and adheres to the surface of the instruments.
  3. Sterilization effect
    Hydrogen peroxide destroys the cell walls, proteins, and DNA of microorganisms through oxidative reactions, rapidly killing bacteria, viruses, and spores.
  4. Plasma treatment
    A high-frequency electric field is activated to excite the hydrogen peroxide vapor into low-temperature plasma. In this state, a large number of active free radicals are released, further enhancing the sterilization effect and decomposing hydrogen peroxide into harmless water vapor and oxygen.
  5. Ventilation and restoration of normal pressure
    After sterilization is complete, sterile air is introduced into the equipment to restore normal pressure. The instruments can be used directly or stored without additional drying or neutralization treatment.

Low-temperature sterilization using plasma technology

Hydrogen peroxide vapor can easily disinfect items or entire rooms. However, when combined with low-temperature plasma technology, the disinfection effect is even more significant. Plasma contains a large number of ions and free electrons, giving it stronger chemical reactivity than ordinary steam, thereby enhancing overall antibacterial performance.

Cold plasma can even directly generate hydrogen peroxide (H₂O₂) in water, quickly producing a disinfectant solution. For example, using dielectric barrier discharge (DBD) technology, hydrogen peroxide concentrations of up to 100 µmol can be produced in water. If the original gas contains water vapor, the amount of H₂O₂ generated may further increase. The higher the moisture content in air plasma, the higher the concentration of hydrogen peroxide produced.

These highly reactive molecules can penetrate microbial cells, causing severe DNA damage and leading to the rapid death of bacteria and other microorganisms. Water treated with air plasma also forms higher concentrations of peroxides. Due to the stronger chemical activity of hydrogen peroxide plasma, its disinfection cycle is significantly shorter and more efficient compared to hydrogen peroxide vapor in neutral gases.

Traditional sterilization techniques vs. hydrogen peroxide gas plasma

Traditional sterilization systems typically rely on a single mechanism to kill bacteria, such as high temperatures or corrosive chemicals. Hydrogen peroxide plasma not only relies on highly reactive ions but also often exhibits synergistic effects.
Hydrogen peroxide vapor sterilization cycles may take several hours, while H₂O₂ plasma treatment can sometimes be completed in less than an hour.
For heat-sensitive materials, hydrogen peroxide plasma can achieve better sterilization results.
Although H₂O₂ must be produced from water and hydrogen peroxide, an appropriate plasma source can rapidly generate the same solution using only water and dilute air.

Advantages of Hydrogen Peroxide Plasma Sterilization

Hydrogen peroxide vapor/plasma sterilization is a safe and non-toxic sterilization method. It is a dry, non-thermal sterilization process that is environmentally friendly and does not produce harmful byproducts like other sterilization methods. Items sterilized using hydrogen peroxide vapor/plasma can be safely handled immediately, as the sterilization chamber is vacuum-flushed with filtered air to remove residues. Another advantage is that hydrogen peroxide vapor enables low-temperature sterilization (typically between 40 and 100°C, or 320 and 380 K). Due to its ability to effectively inactivate microorganisms, the sterilization chamber’s cycle time is relatively short. Most hydrogen peroxide plasma sterilization cycles last less than an hour, with an average cycle time of 35–45 minutes. Hydrogen peroxide plasma is most commonly used for the sterilization of medical devices and surgical instruments.

Advantages of hydrogen peroxide plasma

  1. Using hydrogen peroxide plasma as a low-temperature sterilization method offers the following benefits:
  2. No chemical residues
  3. Operational safety
  4. Environmental safety
  5. Short exposure time.

Disadvantages of hydrogen peroxide plasma

  1. Every disinfection method has its advantages and disadvantages. Let’s take a look at these disadvantages:
  2. Cannot sterilize: liquids, powders, and strong absorbents.
  3. Requires specific synthetic packaging for loads.
  4. The sterilization chamber is relatively smaller than that of an EtO sterilizer.