Size reduction of selenium nanoparticles synthesized from yeast beta glucan using cold atmospheric plasma

The limitations of both inorganic and organic selenium sources, such as low bioavailability and potential toxicity, have driven research towards selenium nanoparticles (SeNPs). In this study, β-glucan was extracted from the cell wall of Kluyveromyces marxianus M59 and subsequently carboxymethylated to enhance its water solubility. Carboxymethylated β-glucan was then utilized for the synthesis of selenium nanoparticles (SeNPs), and their sizes were determined using Scanning Electron Microscopy (SEM) analysis. To reduce the size of larger nanoparticles, Cold Atmospheric Plasma (CAP) treatment was applied, resulting in an approximately 82.4% decrease in particle size. The SeNPs obtained ranged in size from 180 to 83 nm. The synthesized SeNPs were characterized using UV-Vis Spectrophotometry, Fourier-Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction (XRD) analysis. The absorption peak of SeNPs was detected at 330 nm, further confirming their amorphous nature. Additionally, the biological activities of SeNPs, including their antimicrobial, antibiofilm, and antioxidant properties, were investigated. When the antibiofilm activity of SeNPs was evaluated, the highest inhibition rate (43.6 ± 0.1%) was observed at a concentration of 5 mg/mL. In contrast, regarding antimicrobial activity, SeNPs exhibited limited inhibition zones at low concentrations, with a maximum inhibition diameter of 1.20 mm recorded. Antioxidant activity was evaluated through 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, superoxide anion scavenging, and hydroxyl radical scavenging assays. The highest antioxidant activity was determined at 5 mg/mL SeNP concentration (47.7%) at DPPH method. The cytotoxic effects of SeNPs were evaluated on both healthy (L929) and lung cancer (A549) cell lines. The IC₅₀ for L929 cells remained above 200 µg/mL (411 and 390 µg/mL) at both hours (24 and 48 h), whereas in A549 cells, it was approximately 65 µg/mL at 24 h and 34 µg/mL at 48 h. In this study, SeNPs whose particle sizes were reduced through the CAP process were found to exhibit antibiofilm, antioxidant, and non-toxic properties, suggesting their potential for sustainable and different applications such as healthcare, biomaterials, environmental protection, and drug delivery. The findings of this study provide preliminary insights that will guide future research aimed at elucidating the molecular mechanisms of SeNPs, optimising their biocompatibility and targeted applications, integrating them into advanced biomedical and environmental systems, and evaluating their potential for sustainable use.