Fusion PlasmaEncyclopedia

ROS are chemically reactive molecules containing oxygen, including ozone (O₃), hydrogen peroxide (H₂O₂), superoxide (O₂⁻), hydroxyl radicals (OH•), and singlet oxygen (¹O₂). RNS are nitrogen-containing reactive molecules, including nitric oxide (NO), nitrogen dioxide (NO₂), and peroxynitrite (ONOO⁻). Both families are produced naturally in the body at low levels and play essential roles in cell signaling, immune defense, and wound healing. Plasma dramatically increases their local concentration at the treatment site, creating a controlled oxidative burst that the cells interpret as a signal to repair and renew.

When plasma filaments contact ambient air or skin surface moisture, three primary reactions occur: (1) Electron impact dissociation breaks O₂ and N₂ molecules into atomic oxygen and nitrogen; (2) These atoms recombine with ambient molecules to form ozone, nitric oxide, and other reactive species; (3) When the plasma stream hits the skin surface, the reactive species dissolve into the aqueous environment of the stratum corneum and epidermis, where they initiate biochemical cascades. The exact ROS/RNS composition depends on the gas used (argon produces more ROS, air/ambient produces more RNS), energy level, and treatment duration.

Once ROS/RNS penetrate the epidermis, they activate multiple intracellular signaling pathways: (1) Nrf2 pathway — the master regulator of antioxidant response, which upregulates protective enzymes and stimulates fibroblast activity; (2) MAPK/ERK pathway — promotes cell proliferation and collagen gene expression; (3) TGF-β pathway — the primary driver of collagen synthesis and tissue remodeling; (4) NF-κB pathway — modulates inflammatory response and immune cell recruitment. The key therapeutic principle is 'hormesis' — a low dose of oxidative stress triggers a robust protective and regenerative response, much like exercise damages muscle fibers to stimulate growth.

ROS are lethal to microorganisms because they attack multiple cellular targets simultaneously: (1) Lipid peroxidation destroys cell membrane integrity, causing leakage of cellular contents; (2) Protein oxidation denatures enzymes and structural proteins, halting metabolism; (3) DNA damage through base modification and strand breaks prevents replication. Because bacteria and fungi lack the sophisticated antioxidant defense systems of human cells, they are far more susceptible to plasma-generated ROS. Human skin cells can tolerate the ROS dose that kills 99.9% of acne-causing Cutibacterium acnes bacteria — this therapeutic window is the foundation of plasma acne treatment.

The biological effect of ROS/RNS follows a classic hormetic dose-response curve: very low doses have minimal effect, moderate doses trigger regeneration, and excessive doses cause damage. Fusion Plasma's parameter system is designed to operate exclusively in the 'regenerative zone.' For cold plasma, the total ROS dose per session is calibrated to stay below the cytotoxic threshold of keratinocytes. For warm plasma, the thermal + ROS combination is calibrated to create controlled micro-damage that the body can repair within the normal healing timeline. The safety margin is further protected by: limited contact time, moving-tip technique (never holding stationary), and post-treatment antioxidant aftercare that neutralizes any residual ROS.