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  • Publication
    Biosynthesis of Zinc Oxide nanoparticles using plant extracts of Aloe vera and Hibiscus sabdariffa: phytochemical, antibacterial, antioxidant and anti-proliferative studies
    ( 2017-09-01)
    Mahendiran D.
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    Arumai Selvan D.
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    Dilaveez Rehana
    ;
    Senthil Kumar R.
    ;
    Kalilur Rahiman A.
    The zinc oxide (ZnO) nanoparticles were successfully synthesized by using aqueous extracts of Aloe vera gel/leaf and Hibiscus sabdariffa leaf, and characterized by FT IR, UV-Vis, XRD, SEM, and EDX techniques. For comparison purposes, ZnO nanoparticles was also synthesized by chemical method. Phytochemical screening of the A. vera gel and leaf and H. sabdariffa leaf extracts showed the presence of alkaloids, carbohydrates, flavonoids, gums and mucilages, saponins, phenolic compounds, tannins, and terpenoids. FT IR spectra showed the presence of functional groups and protein as the stabilizing agent surrounding the ZnO nanoparticles. UV-Vis spectra of ZnO nanoparticles exhibit the characteristic absorption band in the range of 344–360 nm, which can be assigned to the intrinsic bandgap absorption of ZnO due to the electron transitions from the valence band to the conduction band. Powder XRD patterns confirmed the hexagonal wurtzite structure. Further, the SEM analysis also indicates the hexagonal rod shape structure of the ZnO nanoparticles. EDX spectra confirmed the chemical composition of the ZnO nanoparticles synthesized by both biological and chemical methods. In vitro antibacterial activity of ZnO nanoparticles synthesized by both biological and chemical methods were performed on three Gram (−ve) (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) and one Gram (+ve) (Staphylococcus aureus) bacteria, in which the ZnO nanoparticles obtained by biological method showed excellent bactericidal activity over that obtained by chemical method. All the ZnO nanoparticles showed promising antioxidant activity determined by five different methods such as 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS); 2,2′-diphenyl-1-picrylhydrazyl (DPPH); hydrogen peroxide (H2O2); superoxide radical scavenging; and hydroxyl radical scavenging assays. In vitro cytotoxicity of the ZnO nanoparticles were tested against three cancerous cell lines such as human breast adenocarcinoma (MCF-7), cervical (HeLa) and epithelioma (Hep-2), and one normal human dermal fibroblasts (NHDF) cell lines by MTT assay. Apoptosis induction was further confirmed by flow cytometry and cell cycle arrest. The ZnO nanoparticles obtained by biological method display remarkable cytotoxicity against the MCF-7 cell line, and found to be more potent than the widely used drug cisplatin.
  • Publication
    Surface engineered iron oxide nanoparticles as efficient materials for antibiofilm application
    ( 2022-04-01)
    Velusamy P.
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    Su C.H.
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    Kannan K.
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    Kumar G.V.
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    Anbu P.
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    Overuse of antibiotics has led to the development of multidrug-resistant strains. Antibiotic resistance is a major drawback in the biomedical field since medical implants are prone to infection by biofilms of antibiotic resistant strains of bacteria. With increasing prevalence of antibiotic-resistant pathogenic bacteria, the search for alternative method is utmost importance. In this regard, magnetic nanoparticles are commonly used as a substitute for antibiotics that can circumvent the problem of biofilms growth on the surface of biomedical implants. Iron oxide nanoparticles (IONPs) have unique magnetic properties that can be exploited in various ways in the biomedical applications. IONPs are engineered employing different methods to induce surface functionalization that include the use of polyethyleneimine and oleic acid. IONPs have a mechanical effect on biofilms in presence of an external magnet. In this review, a detailed description of surface-engineered magnetic nanoparticles as ideal antibacterial agents is provided, accompanied by various methods of literature review.
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