New approaches to deal with the growing concern associated with antibiotic-resistant bacteria are emerging daily. Essential oils (EOs) are natural antimicrobial substances with great potential to mitigate this situation. However, their volatile nature, in their liquid-free form, has restricted their generalized application in biomedicine. Here, we propose the use of cellulose acetate (CA)/polycaprolactone (PCL) wet-spun fibers as potential delivery platforms of selected EOs to fight infections caused by Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Twenty EOs were selected and screened for their minimal inhibitory concentration (MIC), using the antibiotic ampicillin as positive control. The cinnamon leaf oil (CLO), cajeput oil (CJO), and the clove oil (CO) were the most effective EOs, against the Gram-positive (MIC < 22.38 mg/mL) and the Gram-negative (MIC < 11.19 mg/mL) bacteria. Uniform microfibers were successfully wet-spun from CA/PCL with an averaged diameter of 53.9 ± 4.5 µm, and then modified by immersion with CLO, CJO and CO at 2 × MIC value. EOs incorporation was confirmed by UV-visible spectroscopy, Fourier-transformed infrared spectroscopy, and thermal gravimetric analysis. However, while microfibers contained ampicillin at MIC (control) after the 72 h modification, the CLO, CO and CJO-loaded fibers registered ≈ 14%, 66%, and 76% of their MIC value, respectively. Data showed that even at small amounts the EO-modified microfibers were effective against the tested bacteria, both by killing bacteria more quickly or by disrupting more easily their cytoplasmic membrane than ampicillin. Considering the amount immobilized, CLO-modified fibers were deemed the most effective from the EOs group. These results indicate that CA/PCL microfibers loaded with EOs can be easily produced with increased antibacterial action, envisioning their use as scaffolding materials for the treatment of infections.

中文翻译：

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活性精油对纤维素乙酸酯/聚己内酯湿纺超细纤维有潜在的生物医学应用潜力，具有物理，热和抗菌作用。

每天都出现新的方法来应对与抗生素抗性细菌有关的日益增长的关注。香精油（EOs）是天然的抗菌物质，具有缓解这种情况的巨大潜力。然而，其无液体形式的挥发性性质限制了它们在生物医学中的普遍应用。在这里，我们建议使用醋酸纤维素（CA）/聚己内酯（PCL）湿纺纤维作为某些EO的潜在传递平台，以对抗由金黄色葡萄球菌（S. aureus）和大肠杆菌（E. coli）引起的感染）。使用抗生素氨苄青霉素作为阳性对照，选择了20个EO，并对其最小抑菌浓度（MIC）进行了筛选。肉桂叶油（CLO），开胃油（CJO）和丁香油（CO）是最有效的EO，对革兰氏阳性（MIC <22.38 mg / mL）和革兰氏阴性（MIC <11.19 mg / mL）细菌。从CA / PCL成功湿纺出均匀的超细纤维，平均直径为53.9±4.5 µm，然后通过以2×MIC值浸入CLO，CJO和CO进行改性。通过紫外-可见光谱，傅立叶变换红外光谱和热重分析确认了EOs的结合。然而，尽管在改性72小时后，微纤维在MIC（对照）处含有氨苄青霉素，但CLO，CO和CJO负载纤维的MIC值分别约为≈14％，66％和76％。数据显示，与氨苄青霉素相比，即使是少量的EO修饰的微纤维，对细菌的杀灭作用也更快，或者更容易破坏细胞质膜。考虑到固定的量，从EOs组认为CLO改性的纤维最有效。这些结果表明，负载有EO的CA / PCL超细纤维可以很容易地生产，并具有增强的抗菌作用，并设想将它们用作治疗感染的支架材料。