Abstract：
Antibiotic resistance has increased in recent years, especially for pathogens like Klebsiella pneumoniae. Discovering and developing new drugs is challenging due to the high resistance of pathogens. Metal nanoparticles have been widely used in recent years to overcome and treat infections. Gallic acid-coated iron oxide nanoparticles (IONPs-GA) were synthesized in a simple and cost-effective method. The morphology characteristics of synthesized IONPs-GA were analyzed using Fourier transform infrared spectroscopy (FTIR), x-ray diffraction analysis (XRD), and scanning electron microscope (SEM) analysis. IONPs were mostly spherical in shape with sizes ranging between 32 and 61 nm. All analyses used in this study confirmed the successful coating of gallic acid to iron oxide. Biological activities were studied phenotypically and on the molecular level, including antibacterial, antibiofilm, and mRNA levels of capsule-associated genes. The results showed high antimicrobial activity of the synthesized nanoparticles against different G+ve and G-ve bacteria. The highest activity was recorded against Staphylococcus aureus (43 mm) and K. pneumoniae (22 mm). The MIC of IONPs against K. pneumoniae was 3.12 mg/mL and SEM analysis showed adhering the IONPs-GA to the cell surface of K. pneumoniae resulted in disrupting the cell membrane. Different concentrations of sub-MIC inhibited K. pneumoniae biofilm formation with the highest inhibition percentage at ½ × MIC (66.86%). Also, the synthesized IONPs-GA differently affected the regulation and mRNA level of capsule-associated genes in K. pneumoniae. The results indicated that IONPs-GA could be useful in biological applications such as in drug delivery and treatment wide range of pathogens. RESEARCH HIGHLIGHTS: Gallic acid was successfully coated into iron oxide nanoparticles synthesized in a simple way. IONPs-GA was morphologically characterized using FTIR, XRD, and SEM. Evaluation the activity of IONPs-GA as antibacterial, antibiofilm, and study the potential level of mRNA affected by IONPs-GA.
摘要：
近年来，抗生素耐药性有所增加，尤其是肺炎克雷伯菌等病原体。由于病原体的高耐药性，发现和开发新药物具有挑战性。近年来，金属纳米粒子已被广泛用于克服和治疗感染。以简单且经济有效的方法合成了没食子酸包覆的氧化铁纳米颗粒（IONP-GA）。利用傅里叶变换红外光谱(FTIR)对合成的IONPs-GA进行了形貌分析,X射线衍射分析(XRD),扫描电镜(SEM)分析。IONP的形状大多为球形，尺寸在32至61nm之间。本研究中使用的所有分析证实了没食子酸成功地涂覆到氧化铁上。在表型和分子水平上研究了生物活性，包括抗菌，抗生物膜,和胶囊相关基因的mRNA水平。结果表明，合成的纳米颗粒对不同的G+ve和G-ve细菌具有较高的抗菌活性。针对金黄色葡萄球菌(43mm)和肺炎克雷伯菌(22mm)记录到最高活性。IONP对肺炎克雷伯菌的MIC为3.12mg/mL,SEM分析显示IONP-GA粘附于肺炎克雷伯菌的细胞表面导致细胞膜破坏。不同浓度的亚MIC抑制肺炎克雷伯菌生物膜形成,在1/2×MIC时抑制百分比最高(66.86%)。此外，合成的IONPs-GA对肺炎克雷伯菌胶囊相关基因的调节和mRNA水平有不同的影响。结果表明，IONP-GA可用于生物应用，例如药物递送和治疗多种病原体。研究重点：没食子酸被成功地包覆到以简单方式合成的氧化铁纳米颗粒中。IONP-GA用FTIR进行了形态学表征，XRD,和SEM。评估IONP-GA的抗菌活性，抗生物膜,并研究受IONP-GA影响的mRNA水平。
