Dosage- and time-dependent antibacterial effect of zinc oxide nanoparticles determined by a highly uniform SERS negating undesired spectral variation

Background Zinc oxide nanoparticles (ZnO NPs) are widely used in household and cosmetic products which imply an increased releasing of these particles into the environment, especially aquatic ecosystems, resulting in the need of assessing the potential toxic effects of ZnO NPS on the aquatic organisms, particularly on microalgae which form the base for food chain of aquatic biota. The present study has investigated the dose- and time-dependent cellular accumulation and the corresponding cytotoxic effects of increasing concentrations of ZnO NPs from 10–200 μg/mL on microalga Haematococcus pluvialis at an interval of 24 h for 96 h. Methods The scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) was used to qualitatively detect the cellular accumulation of ZnO NPs in algal cells, while inductively coupled plasma optical emission spectrometry (ICP OES) was performed to quantify the cell associated-zinc in algal cells. The percentage of cell death, reduction in algal biomass, and loss in photosynthetic pigments were measured to investigate the cytotoxic effects of ZnO NPs on H. pluvialis. Extracellular and intracellular changes in algal cells resulted from the treatment of ZnO NPs were demonstrated through optical, scanning, and transmission electron microscopic studies. Results SEM-EDX spectrum evidenced the accumulation of ZnO NPs in algal biomass and ICP OES results reported a significant (p < 0.05) dose- and time-dependent accumulation of zinc in algal cells from 24 h for all the tested concentrations of ZnO NPs (10–200 μg/mL). Further, the study showed a significant (p < 0.05) dose- and time-dependent growth inhibition of H. pluvialis from 72 h at 10–200 μg/mL of ZnO NPs. The morphological examinations revealed substantial surface and intracellular damages in algal cells due to the treatment of ZnO NPs. Discussion The present study reported the significant cellular accumulation of ZnO NPs in algal cells and the corresponding cytotoxic effects of ZnO NPs on H. pluvialis through the considerable reduction in algal cell viability, biomass, and photosynthetic pigments together with surface and intracellular damages.

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A Mini Review of Antibacterial Properties of ZnO Nanoparticles

Frontiers in Physics ◽

10.3389/fphy.2021.641481 ◽

2021 ◽

Vol 9 ◽

Cited By ~ 3

Author(s):

Sergey V. Gudkov ◽

Dmitriy E. Burmistrov ◽

Dmitriy A. Serov ◽

Maxim B. Rebezov ◽

Anastasia A. Semenova ◽

...

Keyword(s):

Zinc Oxide ◽

Zinc Oxide Nanoparticles ◽

Antibacterial Effect ◽

Antibacterial Properties ◽

World Health ◽

Oxide Nanoparticles ◽

Gram Negative Bacteria ◽

Gram Negative ◽

E Coli ◽

Antibacterial Potential

The development of antibiotic resistance of bacteria is one of the most pressing problems in world health care. One of the promising ways to overcome microbial resistance to antibiotics is the use of metal nanoparticles and their oxides. In particular, numerous studies have shown the high antibacterial potential of zinc oxide nanoparticles (ZnO-NP) in relation to gram-positive and gram-negative bacteria. This mini-review includes an analysis of the results of studies in recent years aimed at studying the antibacterial activity of nanoparticles based on zinc oxide. The dependence of the antibacterial effect on the size of the applied nanoparticles in relation to E. coli and S. aureus is given. The influence of various ways of synthesis of zinc oxide nanoparticles and the main types of modifications of NP-ZnO to increase the antibacterial efficiency are also considered.

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Cytotoxic effects of zinc oxide nanoparticles on cyanobacteriumSpirulina (Arthrospira) platensis

PeerJ ◽

10.7717/peerj.4682 ◽

2018 ◽

Vol 6 ◽

pp. e4682 ◽

Cited By ~ 8

Author(s):

Sinouvassane Djearamane ◽

Yang Mooi Lim ◽

Ling Shing Wong ◽

Poh Foong Lee

Keyword(s):

Electron Microscopy ◽

Zinc Oxide ◽

Cell Viability ◽

Aquatic Environment ◽

Zinc Oxide Nanoparticles ◽

Algal Biomass ◽

Time Dependent ◽

Oxide Nanoparticles ◽

Zno Nps ◽

Cytotoxic Effects

BackgroundThe extensive usage of zinc oxide nanoparticles (ZnO NPs) in industrial and consumer products raises the risk of releasing their residues into the aquatic environment. The presence of ZnO NPs in the aquatic environment could potentially cause cytotoxic effects on aquatic organisms. Thus, investigating the cytotoxic effects of ZnO NPs on microalgae, which form the base for the food web of aquatic biota, is essential to gain information regarding the ecotoxicological effects of metallic oxide nanoparticles in the aquatic ecosystem. Therefore, the present study has investigated in detail the assorted cytotoxic effects of ZnO NPs onS. platensisusing various concentrations of ZnO NPs (10–200 mg/L) from 6 to 96 h to explore the dose- and time-dependent cytotoxic effects.MethodsThe cytotoxic effects were all assessed through quantification of loss in cell viability, reduction in biomass and decrease in photosynthetic pigments such as chlorophyll-a, carotenoids and phycocyanin. The surface interactions of nanoparticles and the subsequent morphological alterations on algal cells were examined by optical and scanning electron microscopy (SEM). The intracellular alterations of algal cells were studied using transmission electron microscopy. Furthermore, Fourier transformed infrared (FTIR) spectrum was obtained to investigate the involvement of algal surface biomolecules in surface binding of ZnO NPs on algal cells.ResultsThe treatment of ZnO NPs onS. platensisexhibited a typical concentration- and time-dependent cytotoxicity. Results showed a significant (p < 0.05) cytotoxicity from 24 h onwards for all tested concentrations of ZnO NPs. The maximum cytotoxicity on algal cells was achieved at 96 h of exposure to ZnO NPs. In comparison with control, the algal cells that interacted with 200 mg/L of ZnO NPs for 96 h showed 87.3 ± 1% loss in cell viability, 76.1 ± 1.7% reduction in algal biomass, 92.5 ± 2.2%, 76.2 ± 2.2% and 74.1 ± 3.4% decrease in chlorophyll-a, carotenoids and phycocyanin contents respectively. Our study confirmed the cytotoxicity of ZnO NPs through the algal growth inhibition with 72 h EC10and EC50values of 1.29 and 31.56 mg/L, respectively. The microscopic examinations of the algal cells that interacted with ZnO NPs showed severe cell membrane and intracellular damage. The SEM EDX spectrum of ZnO NPs treated algal biomass evidenced the surface accumulation of zinc in the biomass. Finally, the FTIR spectrum confirmed the involvement of amino, hydroxyl and carboxylic groups of algal cell wall in the surface interaction of ZnO NPs on the algal cells.DiscussionThe results showed that the treatment of ZnO NPs onS. platensistriggered substantial cytotoxicity and caused cell death. Hence,S. platensiscould be potentially used as a bioindicator for testing toxicity of ZnO NPs in aquatic environment.

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