Department of Biotechnology, Faculty of Converging Sciences and Technologies, Islamic Azad University, Science and Research Branch, Tehran, Iran.
BMC Biotechnol. 2024 Oct 7;24(1):75. doi: 10.1186/s12896-024-00905-x.
Silver nanoparticles are extensively researched for their antimicrobial properties. Cold atmospheric plasma, containing reactive oxygen and nitrogen species, is increasingly used for disinfecting microbes, wound healing, and cancer treatment. Therefore, this study examined the effect of water activated by dielectric barrier discharge (DBD) plasma and gliding arc discharge plasma on the antimicrobial activity of silver nanoparticles from Alborzia kermanshahica.
Silver nanoparticles were synthesized using the boiling method, as well as biomass from Alborzia kermanshahica extract grown in water activated by DBD and GA plasma. The physicochemical properties of the synthesized nanoparticles were evaluated using UV-vis spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), zeta potential analysis, transmission electron microscopy (TEM), and gas chromatography-mass spectrometry (GC-MS) analysis. Additionally, the disk diffusion method was used to assess the antimicrobial efficacy of the manufactured nanoparticles against both Gram-positive and Gram-negative bacteria.
The spectroscopy results verified the presence of silver nanoparticles, indicating their biosynthesis. The highest amount of absorption (1.049) belonged to the nanoparticles synthesized by boiling under GA plasma conditions. Comparing the FTIR spectra of the plasma-treated samples with DBD and GA revealed that the DBD-treated samples had more intense peaks, indicating that the DBD method proved to be more effective in enhancing the functional groups on the silver nanoparticles. The DLS results revealed that the boiling method synthesized silver nanoparticles under DBD plasma treatment had a smaller particle size (149.89 nm) with a PDI of 0.251 compared to the GA method, and the DBD method produced nanoparticles with a higher zeta potential (27.7 mV) than the GA method, indicating greater stability of the biosynthesized nanoparticles. Moreover, the highest antimicrobial properties against E. coli (14.333 ± 0.47 mm) were found in the DBD-treated nanoparticles. TEM tests confirmed that spherical nanoparticles attacked the E. coli bacterial membrane, causing cell membrane destruction and cell death. The GC-MS results showed that compounds like 2-methylfuran, 3-methylbutanal, 2-methylbutanal, 3-hydroxy-2-butanone, benzaldehyde, 2-phenylethanol, and 3-octen-2-ol were much higher in the samples that were treated with DBD compared to the samples that were treated with GA plasma.
The research indicated that DBD plasma was more efficient than GA plasma in boosting the antimicrobial characteristics of nanoparticles. These results might be a cornerstone for future advancements in utilizing cold plasma to create nanoparticles with enhanced antimicrobial properties.
银纳米粒子因其抗菌特性而被广泛研究。冷等离子体含有活性氧和氮物种，越来越多地用于消毒微生物、伤口愈合和癌症治疗。因此，本研究检测了水介质的介电阻挡放电（DBD）等离子体和滑动弧放电等离子体对来自 Alborzia kermanshahica 的银纳米粒子抗菌活性的影响。
使用沸腾法以及在 DBD 和 GA 等离子体水激活下生长的来自 Alborzia kermanshahica 提取物的生物质合成银纳米粒子。使用紫外-可见分光光度法、傅里叶变换红外（FTIR）光谱、动态光散射（DLS）、Zeta 电位分析、透射电子显微镜（TEM）和气相色谱-质谱联用（GC-MS）分析评估合成纳米粒子的物理化学性质。此外，使用圆盘扩散法评估制造的纳米粒子对革兰氏阳性和革兰氏阴性细菌的抗菌功效。
光谱结果证实了银纳米粒子的存在，表明其生物合成。在 GA 等离子体条件下，通过沸腾法合成的纳米粒子具有最高的吸光度（1.049）。与 DBD 和 GA 处理的样品的 FTIR 光谱比较表明，DBD 处理的样品具有更强的峰，表明 DBD 方法在增强银纳米粒子的功能团方面更为有效。DLS 结果表明，在 DBD 等离子体处理下，沸腾法合成的银纳米粒子具有较小的粒径（149.89nm），PDI 为 0.251，而 GA 法合成的纳米粒子具有较高的 Zeta 电位（27.7mV），表明生物合成纳米粒子具有更高的稳定性。此外，对大肠杆菌（14.333±0.47mm）的抗菌性能最高的是 DBD 处理的纳米粒子。TEM 测试证实，球形纳米粒子攻击大肠杆菌细胞膜，导致细胞膜破坏和细胞死亡。GC-MS 结果表明，与 GA 等离子体处理的样品相比，DBD 处理的样品中 2-甲基呋喃、3-甲基丁醛、2-甲基丁醛、3-羟基-2-丁酮、苯甲醛、2-苯乙醇和 3-辛烯-2-醇等化合物的含量更高。
研究表明，DBD 等离子体在提高纳米粒子的抗菌特性方面比 GA 等离子体更有效。这些结果可能为未来利用冷等离子体制造具有增强抗菌性能的纳米粒子提供基础。
