Aqueous extract phyto-mediated synthesis of ZnO nanoparticles and ZnO-bentonite nanocomposites: Physical analysis and investigation of antibacterial activity

IF 2.5 Q2 CHEMISTRY, MULTIDISCIPLINARY

Results in Chemistry Pub Date : 2025-03-12 DOI:10.1016/j.rechem.2025.102190

Jemal Adem , Enyew Amare Zereffa , Teshome Abdo Segne , H.C. Ananda Murthy , Neeraj Kumar Gupta , Temesgen Achamo Orshiso , C.R. Ravikumar , Dhanalakshmi Muniswamy , V.S. Kotakadi

{"title":"Aqueous extract phyto-mediated synthesis of ZnO nanoparticles and ZnO-bentonite nanocomposites: Physical analysis and investigation of antibacterial activity","authors":"Jemal Adem , Enyew Amare Zereffa , Teshome Abdo Segne , H.C. Ananda Murthy , Neeraj Kumar Gupta , Temesgen Achamo Orshiso , C.R. Ravikumar , Dhanalakshmi Muniswamy , V.S. Kotakadi","doi":"10.1016/j.rechem.2025.102190","DOIUrl":null,"url":null,"abstract":"<div><div>Multidrug-resistant (MDR) and highly drug-resistant (HDR) bacteria are responsible for life-threatening infections, prompting interest in phyto-mediated synthesis and the application of inorganic nanoparticles (NPs) and their nanocomposites (NCs) for antimicrobial therapy. This study investigated the synthesis of zinc oxide nanoparticles (ZnO NPs) and ZnO-activated bentonite nanocomposites (ZnO/A-bentonite NCs) using the aqueous leaf extract of <em>Hagenia abyssinica</em> and optimal calcination temperatures of 500 °C and 650 °C, respectively. Characterization by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) confirmed the synthesis and structure of the NPs and NCs, revealing average crystallite sizes of 13.5–28.7 and 3.41–22.3 nm, respectively. The NPs exhibited absorption in the UV-A region, while the NCs showed absorption in the UV-B region. Compositing ZnO NPs with A-bentonite reduced their band gap from 3.24 to 3.07 eV. High-Resolution Transmission Electron Microscopy (HRTEM) of selected ZnO 100 NPs and ZnO/A-bentonite 100 NC showed particles with average sizes of 17.9 and 15.7 nm, respectively. Elemental analysis of purified and A-bentonite revealed an increase in Na₂O content and a decrease in CaO content, indicating Na<sup>+</sup> ions replaced Ca<sup>2+</sup> ions. Significant antimicrobial activity was demonstrated against <em>Escherichia coli</em> (<em>E. coli</em>) and <em>Staphylococcus aureus</em> (<em>S. aureus</em>) bacteria by the leaf extract, ZnO NPs, A-bentonite, and ZnO/A-bentonite NCs at various concentrations, with NPs and NCs synthesized with excess leaf extract exhibiting superior activity. A selected ZnO/A-bentonite 300 NC demonstrated minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 312.5 and 625 μg/mL against <em>E. coli</em> and 156.25 and 312.5 μg/mL against <em>S. aureus</em>, respectively.</div></div>","PeriodicalId":420,"journal":{"name":"Results in Chemistry","volume":"15 ","pages":"Article 102190"},"PeriodicalIF":2.5000,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Results in Chemistry","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2211715625001730","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}

引用次数: 0

Abstract

Multidrug-resistant (MDR) and highly drug-resistant (HDR) bacteria are responsible for life-threatening infections, prompting interest in phyto-mediated synthesis and the application of inorganic nanoparticles (NPs) and their nanocomposites (NCs) for antimicrobial therapy. This study investigated the synthesis of zinc oxide nanoparticles (ZnO NPs) and ZnO-activated bentonite nanocomposites (ZnO/A-bentonite NCs) using the aqueous leaf extract of Hagenia abyssinica and optimal calcination temperatures of 500 °C and 650 °C, respectively. Characterization by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) confirmed the synthesis and structure of the NPs and NCs, revealing average crystallite sizes of 13.5–28.7 and 3.41–22.3 nm, respectively. The NPs exhibited absorption in the UV-A region, while the NCs showed absorption in the UV-B region. Compositing ZnO NPs with A-bentonite reduced their band gap from 3.24 to 3.07 eV. High-Resolution Transmission Electron Microscopy (HRTEM) of selected ZnO 100 NPs and ZnO/A-bentonite 100 NC showed particles with average sizes of 17.9 and 15.7 nm, respectively. Elemental analysis of purified and A-bentonite revealed an increase in Na₂O content and a decrease in CaO content, indicating Na⁺ ions replaced Ca²⁺ ions. Significant antimicrobial activity was demonstrated against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria by the leaf extract, ZnO NPs, A-bentonite, and ZnO/A-bentonite NCs at various concentrations, with NPs and NCs synthesized with excess leaf extract exhibiting superior activity. A selected ZnO/A-bentonite 300 NC demonstrated minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 312.5 and 625 μg/mL against E. coli and 156.25 and 312.5 μg/mL against S. aureus, respectively.

Abstract Image