Cold atmospheric plasma as an alternative decontaminant

Ahead of the next IPC Partners and Healthcare Infection Society Journal Club, focusing on ‘’Integrated IPC and AMS: a global perspective’’ (which you can register here for) I’ve written a blog on this paper discussing ‘’ cold atmospheric plasma. The paper is published in the Journal of Hospital Infection as part of a special issue: Integrated IPC and AMS strategies to reduce infection and AMR in healthcare: a global perspective.

I must admit when I first read the words ‘’cold plasma’’, I had no idea what the technology was and how it worked. However after further reading, cold plasma (as the paper suggests) offers a new and exciting technology for decontamination of healthcare environments. Given the global challenges we face from the threat of antimicrobial resistance, I firmly believe we need to continuously innovate and evaluate new technologies to keep healthcare environments safe.

So, what is atmospheric cold plasma?

Cold atmospheric plasma (CAP) is a plasma activated liquid (PAL), which has antimicrobial efficacy against viral, bacterial and fungal pathogens. PALs produced by CAP are of considerable interest due to the richness of the chemistries that they produce, arising from the interaction of the plasma with the fluid. These PALs are biocidal through the production of reactive species produced by the action of the plasma-induced radicals that impact microbes. Furthermore, initial studies suggests that direct application of cold plasma to surfaces, or PALs in the form of a mist, kills microbes, and these antimicrobial properties could be used to augment conventional cleaning approaches (Upadrasta et al., 2023).

The paper highlights some of the downsides associated with ‘walk away’ technologies such as UV-C and hydrogen peroxide, predominately the evacuation of patients which impacts patient flow and hospital efficiency. A consideration for CAP and PAL derivatives is to characterize any residues and confirm the absence of any adverse consequences to patients, staff and equipment, as the use of CAP without the need to fully vacate the area of patients and staff, would be a major advantage in comparison to ‘walk away’ technologies.

What are the drawbacks?

One significant concern with plasma technology is the potential for the accumulation of toxic gases, such as ozone, in the immediate environment, with the risk of inhalation and long-term exposure to elevated levels, resulting in the need for emission-limiting regulations.

From potential to practice

The authors highlight that while CAP and PALs show significant promise, several important steps are needed before the technology can be widely adopted in healthcare settings. These include:

- Validating safety and efficacy: More robust clinical data are needed to confirm microbial reduction, ensure non-toxicity, and understand potential ozone or residue formation.

- Integrating with current IPC programmes: Cold plasma should complement, not replace manual cleaning.

- Developing international standards: Clear guidance will be required to regulate plasma device design, deployment, and maintenance.

- Supporting global access: Plasma systems could be simpler and cheaper to run than many existing technologies, making them an attractive option for resource-limited settings.

The future of cold plasma

The authors call for a greater collaboration between plasma scientists, engineers, IPC specialists, regulatory agencies, and industry to further evaluate prototypes, customize for use in a clinical setting, and evaluate in well-constructed trials. These authors suggest these trials should confirm the impact of plasma technology on surface
counts, the presence of biofilm, and the overall impact on HCAI rates. Personally, I couldn’t agree more, specifically the impact on dry surface biofilm which plays a role in the persistence of bacteria and transmission of HCAIs.

Cold plasma offers a potentially exciting new alternative for environmental decontamination but there is still work to do in understanding the efficacy, application and safety considerations.  However, in today’s world where we are facing an unprecedented threat from AMR, it is vitally important to evaluate new technologies (like we did with UV-C and HPV) to key the healthcare environment clean and support patient safety.

References

GBD 2021 Antimicrobial Resistance Collaborators. Global burden of bacterial antimicrobial resistance 1990-2021: a
systematic analysis with forecasts to 2050. Lancet. 2024 Sep 28;404(10459):1199-1226.

Humphreys H, Daniels S. Cold atmospheric plasma as an alternative decontaminant to control healthcare-associated infections and antimicrobial resistance - significant potential that can be realized globally. J Hosp Infect. 2025 Jan;155:231-233.

Upadrasta A, Daniels S, Thompson TP, Gilmore B, Humphreys H. In situ generation of cold atmospheric plasma-activated mist and its biocidal activity against surrogate viruses for COVID-19. J Appl Microbiol. 2023 Aug 1;134(8):lxad181.