Analysis of Hydrogen Peroxide Disinfection and Sterilization Technology during the Replacement of High Efficiency Air Filters in Biosafety Cabinets

During the replacement process of high-efficiency air filters in biosafety cabinets, the use of hydrogen peroxide (H ₂ O ₂) for disinfection and sterilization is currently one of the most advanced, reliable, and residual methods, especially suitable for handling high-risk pathogens. The following is a comprehensive analysis of the technology.
Core advantages and principles: Hydrogen peroxide attacks microbial cell membranes, lipids, proteins, and DNA by generating highly oxidative hydroxyl radicals (· OH), achieving broad-spectrum and efficient killing (including bacteria, viruses, fungi, fungal spores, and even some effects on prions). In the scenario of filter replacement, the main technical form is "vaporized hydrogen peroxide (VHP)" or "hydrogen peroxide vapor (HPV)".
Technical process analysis (applied to filter replacement)

Purpose: Before disassembly, kill all microorganisms inside the safety cabinet and on the surface of the filter to minimize the risk of contamination.
Equipment and materials:
VHP generator: a professional equipment that can convert liquid hydrogen peroxide (usually at a concentration of 30% -35%) into dry, uniform micro condensed steam through flash evaporation or vaporization technology.
Specialized hydrogen peroxide sterilizer: a food grade or medical device grade hydrogen peroxide solution typically containing stabilizers.
Circulating pipeline and adapter: used to introduce VHP into a sealed safety cabinet cavity and form a circulation.
Chemical indicators and biological indicators (such as spore strips of thermophilic fatty Bacillus subtilis).
Operation process:
Preparation: Empty the contents of the cabinet, close the front window and exhaust port (for a sealable safety cabinet), seal the air outlet, gap, etc. of the safety cabinet with a special sealing kit or plastic film to form a temporary sealed chamber.
Connection: Connect the output and return air lines of the VHP generator to the appropriate interface of the safety cabinet (such as through the front window opening adapter).
Sterilization cycle:
Dehumidification stage: Reduce the humidity inside the chamber to create conditions for subsequent micro condensation.
Injection stage: Inject vaporized hydrogen peroxide into the chamber to achieve and maintain the target concentration (such as several hundred ppm).
Maintenance phase: Maintain the set concentration for a period of time to ensure that all surfaces and filter depths are exposed.
Ventilation analysis stage: Catalyze hydrogen peroxide into harmless water vapor and oxygen until the concentration is below the safe threshold (usually 1ppm).
Verification: After the cycle is completed, read the color change of the chemical indicator and remove the biological indicator for cultivation to confirm the sterilization effect.
Technical points: The micro condensation characteristics of VHP enable it to form an extremely thin monolayer sterilization film on the surface at room temperature, effectively penetrating gaps and complex structures, and also having the potential to kill microorganisms inside the filter.

Advantage application: Due to the deep sterilization carried out in the first stage, the interior of the safety cabinet and filters are now in a sterile state, greatly reducing the risk of disassembly operations.
Auxiliary measures: Operators still need to wear a full set of PPE. A hydrogen peroxide dry mist generator can be used near the work area to form a protective air curtain locally, further preventing any potential aerosol diffusion (this is not necessary, but as an enhancement measure).

Even after VHP treatment, old filters should still be treated as biohazard waste.
Suggestion: After removal and double-layer sealing, high-pressure sterilization should still be carried out as the final safe disposal method. VHP processing cannot replace the requirement of physical destruction.

For the cleaned installation chamber, a short cycle VHP treatment or hydrogen peroxide wiping can be performed to ensure a highly clean environment for the installation of the new filter.
Analysis of Technical Advantages
Efficient and broad-spectrum: High killing rate, log reduction value (LRV) can usually reach 4-6, which can effectively deal with multidrug-resistant bacteria and spores.
Good material compatibility: There are far more materials compatible with VHP than formaldehyde, and they have extremely low corrosiveness to the metals, plastics, electronic components, and filters inside the safety cabinet (in a dry state).
No harmful residues: The decomposition products are only water and oxygen, non-toxic residues, no need for neutralization, and personnel can safely enter after ventilation, with fast turnover time.
The process can be monitored and validated: real-time monitoring of concentration, temperature, and humidity can be carried out, and quantitative validation can be performed using biological indicators, in compliance with GMP and biosafety quality management requirements.
Strong penetrability: Gas molecules can penetrate deep into gaps, pipelines, and filter fibers that liquid disinfectants cannot reach.
Limitations, risks, and challenges
High equipment and cost: Professional VHP generators and consumables are expensive and require capital investment.
Professional operation required: Operators need specialized training. Improper parameter settings (concentration, time, humidity) may lead to sterilization failure or material damage (such as condensation caused by excessive humidity).
High sealing requirements: Good temporary sealing is needed for the safety cabinet, otherwise steam leakage can lead to insufficient concentration and environmental pollution.
Sensitive to certain materials: High concentrations or condensed states may corrode copper, brass, untreated aluminum, and cause certain rubbers to age.
Cannot replace final treatment: The discarded filter cannot be "non-toxic" and the physical hazards still exist. It must undergo subsequent treatment such as high-pressure sterilization.
Safety risk: High concentration hydrogen peroxide vapor can be irritating to the eyes and respiratory tract, and adequate ventilation and analysis must be ensured.