Umoren Peace Saviour, Kavaz Doga, Nzila Alexis, Sankaran Saravanan Sankaran, Umoren Saviour A
Department of Bioengineering, Cyprus International University, via Mersin 10, Nicosia 98258, Turkey.
Department of Bioengineering, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia.
Polymers (Basel). 2022 Apr 29;14(9):1832. doi: 10.3390/polym14091832.
Chitosan-copper oxide (CHT-CuO) nanocomposite was synthesized using olive leaf extract (OLE) as reducing agent and CuSO4⋅5H2O as precursor. CHT-CuO nanocomposite was prepared using an in situ method in which OLE was added to a solution of chitosan and CuSO4⋅5H2O mixture in the ratio of 1:5 (v/v) and heated at a temperature of 90 °C. The obtained CHT-CuO nanocomposite was characterized using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), ultraviolet-visible (UV-Vis) spectrophotometry, energy-dispersive X-ray spectroscopy (EDAX), Fourier transform infrared spectroscopy (FTIR), and high-resolution transmission electron microscopy (TEM). TEM results indicated that CHT-CuO nanocomposite are spherical in shape with size ranging from 3.5 to 6.0 nm. Antibacterial activity of the synthesized nanocomposites was evaluated against Gram-positive (Bacillus cereus, Staphyloccous haemolytica and Micrococcus Luteus) and Gram-negative (Escherichia coli, Pseudomonas citronellolis, Pseudomonas aeruginosa, kliebisella sp., Bradyrhizobium japonicum and Ralstonia pickettii) species by cup platting or disc diffusion method. Overall, against all tested bacterial strains, the diameters of the inhibition zone of the three nanocomposites fell between 6 and 24 mm, and the order of the antimicrobial activity was as follows: CuO-1.0 > CuO-0.5 > CuO-2.0. The reference antibiotic amoxicillin and ciprofloxacin showed greater activity based on the diameter of zones of inhibition (between 15−32 mm) except for S. heamolytica and P. citronellolis bacteria strains. The nanocomposites MIC/MBC were between 0.1 and 0.01% against all tested bacteria, except S. heamolityca (>0.1%). Based on MIC/MBC values, CuO-0.5 and CuO-1.0 were more active than CuO-2.0, in line with the observations from the disc diffusion experiment. The findings indicate that these nanocomposites are efficacious against bacteria; however, Gram-positive bacteria were less susceptible. The synthesized CHT-CuO nanocomposite shows promising antimicrobial activities and could be utilized as an antibacterial agent in packaging and medical applications.
以橄榄叶提取物（OLE）为还原剂、五水硫酸铜（CuSO₄⋅5H₂O）为前驱体制备了壳聚糖-氧化铜（CHT-CuO）纳米复合材料。采用原位法制备CHT-CuO纳米复合材料，即将OLE按1:5（v/v）的比例加入壳聚糖与CuSO₄⋅5H₂O的混合溶液中，并在90℃加热。利用场发射扫描电子显微镜（FE-SEM）、X射线衍射（XRD）、紫外可见（UV-Vis）分光光度法、能量色散X射线能谱（EDAX）、傅里叶变换红外光谱（FTIR）和高分辨率透射电子显微镜（TEM）对所得的CHT-CuO纳米复合材料进行表征。TEM结果表明，CHT-CuO纳米复合材料呈球形，尺寸范围为3.5至6.0纳米。通过杯碟法或纸片扩散法对合成的纳米复合材料针对革兰氏阳性菌（蜡样芽孢杆菌、溶血葡萄球菌和藤黄微球菌）和革兰氏阴性菌（大肠杆菌、香茅假单胞菌、铜绿假单胞菌、克雷伯菌属、日本慢生根瘤菌和皮氏罗尔斯顿菌）的抗菌活性进行了评估。总体而言，针对所有测试的细菌菌株，三种纳米复合材料的抑菌圈直径在6至24毫米之间，抗菌活性顺序如下：CuO-1.0＞CuO-0.5＞CuO-2.0。除溶血葡萄球菌和香茅假单胞菌菌株外，参考抗生素阿莫西林和环丙沙星基于抑菌圈直径显示出更高的活性（在15 - 32毫米之间）。纳米复合材料对所有测试细菌的最低抑菌浓度/最低杀菌浓度在0.1%至0.01%之间，除溶血葡萄球菌（＞0.1%）外。基于最低抑菌浓度/最低杀菌浓度值，CuO-0.5和CuO-1.0比CuO-2.0更具活性，这与纸片扩散实验的观察结果一致。研究结果表明，这些纳米复合材料对细菌有效；然而，革兰氏阳性菌的敏感性较低。合成的CHT-CuO纳米复合材料显示出有前景的抗菌活性，可作为抗菌剂用于包装和医疗应用。
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