Abstract
<jats:p>Nanobubbles (NBs), gas-filled bubbles with diameters below 1 µm, have attracted significant interest due to their unusual stability in water and their potential to enhance processes across environmental, agricultural, medical, energy, and food applications. However, significant challenges persist regarding their reproducible generation, reliable characterization, and the fundamental mechanisms responsible for their apparent stability. This Perspective critically assess the current state of knowledge in these three areas based on recent literature and from our own research. Commonly used NB generation methods were evaluated, emphasizing the importance of energy efficiency and standardized reporting of experimental conditions to enable meaningful comparisons between technologies. NB characterization approaches were also examined, highlighting that widely used light-scattering techniques cannot unequivocally distinguish NBs from particulate contaminants and identified the need of NB reference standards. Additionally, best-practice recommendations are proposed to improve confidence in reported results including freeze-thaw verification and reporting particle size distribution data. Lastly, current models of NB stability were critically evaluated, particularly the fundamental limitations associated with applying conventional colloidal theories to gaseous interfaces. Molecular-level investigations are essential for developing robust models capable of explaining NB stability and guiding future advances in the field.</jats:p>