该研究采用超声波辅助制备了不同浓度和粒径的百里香精油纳米乳液,并探索其浓度和粒径对大肠杆菌、铜绿假单胞菌、金黄色葡萄球菌和枯草芽孢杆菌的抑菌效果。通过透射电镜观察到纳米乳液均呈现完好的球形,平均粒径均在50 nm左右,与纳米粒度分析仪测得结果相近;傅里叶红外光谱分析表明,超声功率的改变可以调控纳米乳液的粒径,但对其组成成分的化学结构没有影响。在抑菌性的研究中发现,百里香精油纳米乳液的浓度变化对不同菌株的抗菌效果有显著影响(P<0.05),而粒径大小对不同菌株的抗菌效果的影响具有差异性:对铜绿假单胞菌的抗菌效果的影响最为显著(P<0.05),而对大肠杆菌的影响不如铜绿假单胞菌明显。该研究结果表明,利用百里香精油纳米乳液的浓度和粒径的优化组合可以提升其对细菌的抑制效果。
This research used ultrasonic-assisted technique to prepare thyme essential oil nanoemulsion with different concentrations and droplet sizes, then explored the inhibitory effects of concentration and droplet size of nanoemulsion on Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis. It was observed by transmission electron microscopy that the nanoemulsions were perfectly spherical with the average droplet size of 50 nm, and were comparable to the results measured by particle size analyzer. Fourier transform infrared spectroscopy showed that the change of ultrasonic power could adjust the droplet size of the nanoemulsion but had no effect on the chemical structure of its components. Antimicrobial activity research proved that the concentration of thyme essential oil nanoemulsion had a significant effect on the antibacterial of different strains (P<0.05), while the droplet size had difference on antibacterial effect of different strains. P. aeruginosa had the most significant effect (P<0.05), while that of E. coli was not as apparent as that of P. aeruginosa. The results showed that the optimal combination of the concentration and droplet size of the thyme essential oil nanoemulsion could enhance its antibacterial effect.
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