Effects of Nitrogen, Oxygen, and Hydrogen Nanobubbles on Human Lung Fibroblast Viability

Nanobubbles (NBs) (<1 µm) exhibit unique physicochemical properties and high stability, which have potential applications in biological systems, including microbial metabolism enhancement, fibroblast proliferation, and tumor inhibition. However, the influence of different gaseous components on cell viability remains unclear. This study examined the effects of nitrogen, oxygen, and hydrogen NBs on human lung fibroblast cell (MRC-5) viability. NBs were generated in a Dulbecco’s modified Eagle’s medium using a gas–liquid mixing method and characterized by a nanoparticle tracking analysis. After 48 h of culture, cell viability increased 1.34-, 1.30-, and 1.29-fold for nitrogen, oxygen, and hydrogen NBs, respectively, with only nitrogen NBs showing a significant increase (p < 0.05). Flow cytometry with carboxyfluorescein succinimidyl ester analysis showed no difference in proliferation among groups, indicating that enhanced viability might result from gas-specific effects rather than direct stimulation of cell division. These findings highlight the potential biomedical applications of nanobubbles and their constituent gases.