Studies on the physical properties of green synthesized cerium oxide nanoparticles using Melia dubia leaf extract

Author(s):  
Nadar Jebamerlin Selvaraj Janaki ◽  
D.S. Ivan Jebakumar ◽  
P Sumithraj Premkumar
Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1111
Author(s):  
Min-Jae Lee ◽  
Seon-Young Park ◽  
A-Young Sung

The functional hydrogel lens containing 2-hydroxyethylmethacrylate (HEMA) was manufactured by thermal polymerization. The physical properties of the produced hydrogel lens were measured and analyzed. In this study, HEMA, ethylene glycol dimethacrylate (EGDMA), and azobisisobutyronitrile (AIBN) were used for thermal copolymerization. Additionally, poly (ethylene glycol) methyl ether methacrylate (PEGMEMA), 3-(Triethoxysilyl) propyl isocyanate (TEPI), and cerium(Ⅳ) oxide nanoparticles were used as additives to make a functional hydrogel lens. The mixture was heated at 100 °C for 90 min to produce the hydrogel ophthalmic lens by the cast mold method. The resulting physical properties showed that the water content and refractive index of the sample were in the ranges of 38.06~42.11% and 1.426~1.436, respectively. The addition of cerium oxide nanoparticles lowered the contact angle and allowed the hydrogel lens to block UV light. The tensile strength was also improved by 52.13% through cerium oxide nanoparticles, and up to 123.4% by using TEPI. Based on the results of this study, the produced ophthalmic lens is suitable for durable, UV-blocking high-performance lenses.


2020 ◽  
Vol 20 (11) ◽  
pp. 6871-6876
Author(s):  
Su-Mi Shin ◽  
A-Young Sung

The optical, physical and polymerization property of hydrogel ophthalmic lenses made by cerium nanoparticles containing 4-chlorostyrene as a base hydrogel material were analyzed. Cerium oxide nanoparticles were used as additive. And HEMA, 4-chlorostyrene and a cross-linker EGDMA were copolymerized in the presence of AIBN as an initiator. Also, the polymerization property such as TGA and absorbance of the prepared lens were measured. Measurement of the polymerization characteristics of the copolymerized material showed that TGA was found that the addition of cerium oxide increased thermal stability. The physical properties of the basic lenses were totally satisfied and breaking strength gradually increased with the addition amount of 4-Chlorostyrene. Cerium nanoparticles are considered to satisfy the basic requirements of hydrogel lenses and UV-blocking amount gradually increased according to the addition ratio of cerium oxide nanoparticles without affecting the basic physical properties. Therefore, these materials can be used effectively as additives for ophthalmic hydrogel lenses.


2015 ◽  
Vol 49 ◽  
pp. 408-415 ◽  
Author(s):  
Ayyakannu Arumugam ◽  
Chandrasekaran Karthikeyan ◽  
Abdulrahman Syedahamed Haja Hameed ◽  
Kasi Gopinath ◽  
Shanmugam Gowri ◽  
...  

2019 ◽  
Vol 4 (3) ◽  
pp. 108-112
Author(s):  
Ali Es-haghi ◽  
Saynaz Aseyd Nezhad

Introduction: Free radicals have singlet electron in their outer layer rendering them high reactivity against biomolecules (i.e., DNA, carbohydrates, proteins, and lipids). Oxidative stress is created when the production of free radicals exceeds their removal by antioxidant systems and is involved in the pathogenesis of several diseases such as diabetes, arthritis, inflammatory conditions, and various cancers. Regarding the therapeutic potential of nanoparticles (NPs) in human diseases, the purpose of this study was to synthesize cerium oxide NPs using Origanum majorana leaf extract. Methods: Cerium oxide nanoparticles (CeO2 -NPs) were synthesized using aqueous leaf extract of O. majorana. The sizes of NPs were characterized by a particle size analyzer. The antioxidant properties of the CeO2 -NPs were determined by Ferric-reducing antioxidant power (FRAP) assay. The anti-inflammatory effects of the NPs were also determined by measuring gene expressions of IL-1β and IL-10 using real-time polymerase chain reaction (PCR). Results: The CeO2 -NPs were successfully synthesized using O. majorana leaf extract. The results of FRAP assay showed that the anti-oxidant activities of CeO2 -NPs at concentrations of 50, 100, and 400 μg/mL were 75%, 77.1%, and 94.5%, respectively. Moreover, interleukin 10 (IL-10) gene expressions increased by 4.6 folds while the expression of IL-1β gene decreased by 0.75-fold in HUVECs. Conclusion: The CeO2 -NPs synthesized using the aqueous extract of O. majorana demonstrated antioxidant and anti-inflammatory properties. Therefore, these NPs can be used as potential therapeutic agents in medicine.


2018 ◽  
Vol 35 (4) ◽  
pp. 791-798 ◽  
Author(s):  
Thirunavukkarasu Arunachalam ◽  
Muthukumaran Karpagasundaram ◽  
Nithya Rajarathinam

Abstract Cerium oxide nanoparticles (CONPs) were prepared using ultrasound assisted leaf extract of Prosopis juliflora acting as a reducing as well as stabilizing agent. The synthesized CONPs were characterized by ultraviolet-visible absorption spectroscopy (UV-Vis), particle size analyzer (PSA), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM). From the UV-Vis analysis, the optical band gap of the prepared CONPs (Eg = 3.62 eV) was slightly increased as compared to the bulk ceria (Eg = 3.19 eV). The phytochemicals in the extract reduced the particle size to 3.7 nm ± 0.3 nm, as it is evident from the PSA. FT-IR results confirmed the Ce-O stretching bands by showing the peaks at 452 cm-1. The Raman spectrumshowed a characteristic peak shift for CONPs at 461.2 cm-1. XRD analysis revealed the cubic fluorite structure of the synthesizednanoparticles with the lattice constant, a of 5.415 Å and unit cell volume, V of 158.813 Å3. XPS signals were used to determine the concentration of Ce3+ and Ce4+ in the prepared CONPs and it was found that major amount of cerium exist in the Ce4+ state. HRTEM images showed spherical shaped particles with an average size of 15 nm. Furthermore, the antibacterial activity of the prepared CONPs was evaluated and their efficacies were compared with the conventional antibiotics using disc diffusion assay against a set of Gram positive (G+) bacteria (Staphylococcus aureus, Streptococcus pneumonia) and Gram negative (G-) bacteria (Pseudomonas aeruginosa, Proteus vulgaris). The results suggested that CONPs showed antibacterial activity with significant variations due to the differences in the membrane structure and cell wall composition among the two groups tested.


2020 ◽  
Vol 16 (5) ◽  
pp. 816-828
Author(s):  
Gurdeep Rattu ◽  
Nishtha Khansili ◽  
Prayaga M. Krishna

Background: Cerium oxide nanoparticles (nanoceria) are efficient free-radical scavengers due to their dual valence state and thus exhibit optical and catalytic properties. Therefore, the main purpose of this work was to understand the peroxidase mimic activity of polymer-stabilized nanoceria for enzyme-less H2O2 sensing by fluorescence spectrometer. Objective: This research revealed the development of fluorescence hydrogen peroxide nanosensor based on the peroxidase-like activity of polyacrylic acid stabilized nanoceria (PAA-CeO2 Nps). Methods: PAA-CeO2 Nps were synthesized by simple cross-linking reaction at a low temperature and characterized by XRD, SEM, Zeta potential, TGA, FT-IR and UV-VIS spectroscopic analysis. H2O2 sensing was performed by a fluorescence spectrometer. Results:: The synthesized polymer nanocomposite was characterized by XRD, SEM, TGA, FT-IR and UV-VIS spectroscopic analysis. The XRD diffraction patterns confirmed the polycrystalline nature and SEM micrograph showed nanoparticles having hexagonal symmetry and crystallite size of 32 nm. The broad peak of Ce–O bond appeared at 508 cm-1. UV-VIS measurements revealed a welldefined absorbance peak around 315 nm and an optical band-gap of 3.17 eV. As synthesized PAACeO2 Nps effectively catalysed the decomposition of hydrogen peroxide (H2O2) into hydroxyl radicals. Then terephthalic acid was oxidized by hydroxyl radical to form a highly fluorescent product. Under optimized conditions, the linear range for determination of hydrogen peroxide was 0.01 - 0.2 mM with a limit of detection (LOD) of 1.2 μM. Conclusion: The proposed method is ideally suited for the sensing of H2O2 at a low cost and this detection system enabled the sensing of analytes (sugars), which can enzymatically generate hydrogen peroxide.


2018 ◽  
Vol 6 (2) ◽  
pp. 111-115 ◽  
Author(s):  
Azadeh Montazeri ◽  
Zohreh Zal ◽  
Arash Ghasemi ◽  
Hooman Yazdannejat ◽  
Hossein Asgarian-Omran ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document