scholarly journals Facile Synthesis, Characterization, Photocatalytic Activity, and Cytotoxicity of Ag-Doped MgO Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2915
Author(s):  
ZabnAllah M. Alaizeri ◽  
Hisham A. Alhadlaq ◽  
Saad Aldawood ◽  
Mohd Javed Akhtar ◽  
Mabrook S. Amer ◽  
...  

Due to unique physicochemical properties, magnesium oxide nanoparticles (MgO NPs) have shown great potential for various applications, including biomedical and environmental remediation. Moreover, the physiochemical properties of MgO NPs can be tailored by metal ion doping that can be utilized in photocatalytic performance and in the biomedical field. There is limited study on the photocatalytic activity and biocompatibility of silver (Ag)-doped MgO NPs. This study was planned for facile synthesis, characterization, and photocatalytic activity of pure and silver (Ag)-doped MgO NPs. In addition, cytotoxicity of pure and Ag-doped MgO NPs was assessed in human normal umbilical vein endothelial cells (HUVECs). Pure MgO NPs and Ag-doped (1, 2, 5, and 7.5 mol%) MgO NPs were prepared via a simple sol-gel procedure. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS) were used to characterize the prepared samples. XRD results showed the preparation of highly crystalline NPs with no impurity peaks. TEM and SEM studies indicate smooth surfaces with almost spherical morphology of MgO NPs, and Ag-doping did not change the morphology. Elemental composition study suggested that Ag is uniformly distributed in MgO particles. Intensity of the PL spectra of MgO NPs decreased with increasing the concentration of Ag dopants. In comparison to pure MgO NPs, Ag-MgO NPs showed higher degradation of methylene blue (MB) dye under UV irradiation. The improved photocatalytic activity of Ag-MgO NPs was related to the effect of dopant concentration on reducing the recombination between electrons and holes. Cytotoxicity studies showed good biocompatibility of pure and Ag-doped MgO NPs with human normal umbilical vein endothelial cells (HUVECs). These results highlighted the potential of Ag-doped MgO NPs in environmental remediation.

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 106 ◽  
Author(s):  
Xin Gao ◽  
Chen Wang ◽  
Qixiang Xu ◽  
Hongjie Lv ◽  
Ting Chen ◽  
...  

A novel N-doped K3Ti5NbO14@TiO2 (NTNT) core-shell heterojunction photocatalyst was synthesized by firstly mixing titanium isopropoxide and K3Ti5NbO14 nanobelt, and then calcinating at 500 °C in air using urea as the nitrogen source. The samples were analyzed by X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis absorption spectroscopy and X-ray photoelectron spectroscopic (XPS) spectra. Anatase TiO2 nanoparticles were closely deposited on the surface of K3Ti5NbO14 nanobelt to form a nanoscale heterojunction structure favorable for the separation of photogenerated charge carriers. Meanwhile, the nitrogen atoms were mainly doped in the crystal lattices of TiO2, resulting in the increased light harvesting ability to visible light region. The photocatalytic performance was evaluated by the degradation of methylene blue (MB) under visible light irradiation. The enhanced photocatalytic activity of NTNT was ascribed to the combined effects of morphology engineering, N doping and the formation of heterojunction. A possible photocatalytic mechanism was proposed based on the experimental results.


1998 ◽  
Vol 66 (11) ◽  
pp. 5337-5343 ◽  
Author(s):  
Rajashri G. Deshpande ◽  
Mahfuz B. Khan ◽  
Caroline Attardo Genco

ABSTRACT Invasion of host cells is believed to be an important strategy utilized by a number of pathogens, which affords them protection from the host immune system. The connective tissues of the periodontium are extremely well vascularized, which allows invading microorganisms, such as the periodontal pathogen Porphyromonas gingivalis, to readily enter the bloodstream. However, the ability of P. gingivalis to actively invade endothelial cells has not been previously examined. In this study, we demonstrate that P. gingivalis can invade bovine and human endothelial cells as assessed by an antibiotic protection assay and by transmission and scanning electron microscopy. P. gingivalis A7436 was demonstrated to adhere to and to invade fetal bovine heart endothelial cells (FBHEC), bovine aortic endothelial cells (BAEC), and human umbilical vein endothelial cells (HUVEC). Invasion efficiencies of 0.1, 0.2, and 0.3% were obtained with BAEC, HUVEC, and FBHEC, respectively. Invasion of FBHEC and BAEC by P. gingivalis A7436 assessed by electron microscopy revealed the formation of microvillus-like extensions around adherent bacteria followed by the engulfment of the pathogen within vacuoles. Invasion of BAEC by P. gingivalisA7436 was inhibited by cytochalasin D, nocodazole, staurosporine, protease inhibitors, and sodium azide, indicating that cytoskeletal rearrangements, protein phosphorylation, energy metabolism, andP. gingivalis proteases are essential for invasion. In contrast, addition of rifampin, nalidixic acid, and chloramphenicol had little effect on invasion, indicating that bacterial RNA, DNA, and de novo protein synthesis are not required for P. gingivalisinvasion of endothelial cells. Likewise de novo protein synthesis by endothelial cells was not required for invasion by P. gingivalis. P. gingivalis 381 was demonstrated to adhere to and to invade BAEC (0.11 and 0.1% efficiency, respectively). However, adherence and invasion of the corresponding fimA mutant DPG3, which lacks the major fimbriae, was not detected. These results indicate thatP. gingivalis can actively invade endothelial cells and that fimbriae are required for this process. P. gingivalisinvasion of endothelial cells may represent another strategy utilized by this pathogen to thwart the host immune response.


2011 ◽  
Vol 345 ◽  
pp. 365-369
Author(s):  
Yan Shi ◽  
Chun Jing Zhang

.Purposes,To explore the effects of carnosine on high glucose-induced apoptosis of human umbilical vein endothelial cells (HUVECs). Methods HUVECs were cultured in vitro. The cellular apoptotic model was made by the addition of high glucose (25 mmol/L), the group of high glucose and carnosine was administered by the addition of high glucose (25 mmol/L) with carnosine (20 mmol/L). In addition, cell apoptosis was detected by the electron microscopy and AnnexinV/PI flow cytometry. Results Compared with the control group, high glucose could induce HUVECs apoptosis under electron microscopy and AnnexinV/PI flow cytometry, while 20 mmol/L carnosine could inhibit the apoptosis induced by high glucose significantly (##P <0.05). Conclusion In this study, carnosine could inhibit high-glucose induced apoptosis of human umbilical vein endothelial cells.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Ke-Jian Ju ◽  
Ming Zhang ◽  
Qian-Li Zhang ◽  
Jie Wei ◽  
Ai-Jun Wang

Rambutan-like ZnO hierarchical hollow microspheres (ZnO HHMs) were constructed under hydrothermal conditions, using carboxyl methyl starch (CMS) as a soft template. The resulting products were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The experimental parameters and growth mechanism of rambutan-like ZnO HHMs were discussed in some detail. The as-prepared samples displayed improved photocatalytic activity for the degradation of rhodamine B under ultraviolet (UV) irradiation.


2021 ◽  
Author(s):  
cheng xiaoni ◽  
Yalei Pan ◽  
Zhishu Tang ◽  
Rui Zhou ◽  
Haichao Zhang ◽  
...  

Abstract Background: Zhengyuan prescription (ZYP) is a Chinese herbal medicine used in clinical practice to protect against radiotherapy-induced injuries. In this study, we investigate the protective effect of ZYP against X-ray-induced injury of human umbilical vein endothelial cells (HUVECs), and we explore the mechanisms underlying this effect.Methods: After 3 h of ZYP intervention, the cells in the ZYP group were irradiated with 6 Gy X-rays and cultured for 48 h. Subsequently, the cell viability, cell morphology, mitochondrial membrane potential, and apoptosis and oxidative stress markers were observed, as well as the expressions of apoptotic and oxidative stress proteins.Results: The obtained results demonstrate that exposure to X-rays promotes cell death, reduces mitochondrial membrane potential, and induces the pirroduction of intracellular reactive oxygen species (ROS). Pretreatment with ZYP reverses these effects to a great extent. Moreover, it up-regulates the expression of the B-cell lymphoma 2 (Bcl-2) apoptosis inhibitor protein while down-regulating the expressions of Bcl-2-associated X protein (Bax), caspase-3, and caspase-9. Interestingly, ZYP can also inhibit oxidative stress injury by activating the expression of Nrf2 (Nuclear Factor E2 related factor) regulated antioxidant enzyme genes such as Heme oxygenase 1 (HO-1) and NAD(P)H:quinone oxidoreductase-1 (NQO1)Conclusions: This study is the first to demonstrate that ZYP suppresses X-ray-induced injury of HUVECs by activating the Nrf2 signaling pathway.


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