Carbon Monoxide in Plasma and Agriculture: Just a Foe or a Potential Friend?

Abstract

Carbon monoxide is infamously known for its toxicity when administrated in high doses. In this article, we review some of the evidence for therapeutic effects of CO used in biology, when CO is delivered in small quantities. It is argued that plasmas in this context are an attractive in situ source for the process of alleviating the risks related to CO storage. Moreover, synergic effects of CO with other reactive species produced by plasma may be used in the future for applications such as bacterial infection, wound healing, and cancer treatment.

Production of carbon monoxide from a He/CO2 plasma jet as a new strategy for therapeutic applications

“…In a previous study, we explained that, to ensure safe conditions, the percentage of COHb in the blood has to be lower than 10%. [ 23 ] For example, the exposure time must not exceed 12 min for 1000 ppm. The maximum CO produced by the plasma jet was 2000 ppm, meaning that a treatment time of a couple of minutes is safe.…”

“…Despite its potentially lethal consequences when inhaled at high concentrations, low doses of CO appear to have many beneficial effects for human health and has a broad spectrum of biological activities such as anti-inflammatory, vasodilatory, antiapoptotic, and antiproliferative effects. [19][20][21][22][23] It has been demonstrated in multiple preclinical models of disease that CO can be used in various applications such as organ transplantation and preservation, tissue ischemia, inflammatory and metabolic disorders. [20,22,24] Surprisingly, the potential role of CO generated by a plasma jet in the treatment of pathological disorders has been completed neglected so far.…”

“…To ensure safe conditions, the exposure time must not exceed 12 min for 1000 ppm, 50 min for 200 ppm, and is infinite for 25 ppm. [ 23 ]…”

“…If the amounts of CO in the blood are such that the oxygencarrying capacity of hemoglobin is severely compromised, this can lead to tissue hypoxia and cause irreversible damage. [23,25] Due to the toxicity of this gas, it is usually recommended that long-term exposure should not exceed 25 ppm in 8 h in the United States, 30 ppm in Germany, and 50 ppm in France. [26,27] In fact, the important parameter to consider is not the concentration of CO, but the percentage of COHb in the blood.…”

“…To ensure safe conditions, the exposure time must not exceed 12 min for 1000 ppm, 50 min for 200 ppm, and is infinite for 25 ppm. [23] Today, the two main systems used to deliver CO in medicine are CO inhalation and CO-releasing molecules (CO-RMs). Inhalation of small amounts of CO gas, from 100 to 1000 ppm, has already been proven to be effective in medicine and has been used for clinical applications.…”