The present work reports the green synthesis of MgO nanoparticles (G-MgO NPs) using Carica papaya leaf extract, and a shape dependent density functional investigation for MgO NPs on their antimicrobial activity, for the first time. The synthesized G-MgO nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and Energy dispersive X-ray analysis (EDS). These methods confirmed the presence of the synthesized G-MgO nanoparticles in the range of 20–100 nm with the shape of dense rock. The larger particles of G-MgO NPs resulted from the agglomeration of smaller nanoparticles. The G-MgO NPs are observed to show reasonable antimicrobial activity against the microorganism Bacillus subtilis. A detailed theoretical study under density functional theory (DFT) shows that our synthesized dense rock shaped MgO nanoparticles are better candidate for biological interactions in comparison to the convensional spherical counterpart. The results show that the green synthesis of magnesium oxide nanoparticles using Carica papaya leaf extract can be an alternative to chemical and physical methods with possible biomedicinal applications in addition.

Graphic Abstract

中文翻译：

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番木瓜叶提取物绿色合成致密MgO纳米颗粒及其形状依赖性抗菌活性：联合实验和DFT研究

本工作首次报道了用番木瓜叶提取物进行绿色合成的MgO纳米颗粒（G-MgO NPs），以及关于MgO NPs的抗菌活性的形状依赖性密度泛函研究。合成的G-MgO纳米粒子通过X射线衍射（XRD），傅立叶变换红外光谱（FT-IR），扫描电子显微镜（SEM）和能量色散X射线分析（EDS）进行表征。这些方法证实了合成的G-MgO纳米颗粒的存在范围为20–100 nm，具有致密的岩石形状。G-MgO NP的较大颗粒是由较小的纳米颗粒附聚而成。观察到G-MgO NP对微生物显示出合理的抗菌活性枯草芽孢杆菌。根据密度泛函理论（DFT）进行的详细理论研究表明，与常规球形配对物相比，我们合成的致密岩石状MgO纳米粒子更适合生物相互作用。结果表明，使用番木瓜叶提取物绿色合成氧化镁纳米颗粒可以替代化学和物理方法，此外还可能具有生物医学应用。

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