DFT and SERS Study of Adsorption of 1,4-Dimethoxy-2-nitro-3-methylanthracene-9,10-dione onto Silver Nanoparticles

2016 ◽  
Vol 69 (1) ◽  
pp. 76 ◽  
Author(s):  
K. Geetha ◽  
T. N. Rekha ◽  
M. Umadevi ◽  
Beulah J.M. Rajkumar ◽  
G.V. Sathe ◽  
...  

Surface-enhanced Raman scattering (or spectroscopy), commonly known as SERS, has been employed to investigate the adsorption mechanism and orientation of 1,4-dimethoxy-2-nitro-3-methylanthracene-9,10-dione (DMNMAD) molecule onto silver. Silver nanoparticles (Ag NPs) were synthesized based on a solution combustion method using citric acid as a fuel. Scanning electron microscopy and transition electron microscopy studies confirm the crystalline nature and morphology of the synthesized silver nanoparticles. Theoretical normal Raman spectra (nRs) and SERS spectra of the DMNMAD molecule, simulated based on DFT/B3PW91 level of theory were validated experimentally. Experimental and theoretical vibrational modes correlate well, confirming the reliable assignments of the vibrational bands. Enhancement of C=O stretching and C–H in-plane vibrational modes in the SERS spectrum indicates the ‘stand-on’ orientation of the molecule on the silver nanoparticles after adsorption. The frontier molecular orbitals confirm the charge transfers between the molecule and silver nanoparticles following the process of adsorption. As anthraquinone derivatives have been recently used as potent anti-tumour drugs, the adsorption studies reported in the current investigation can pave way to the potential application of DMNMAD in drug delivery.

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
M. Anuratha ◽  
A. Jawahar ◽  
M. Umadevi ◽  
N. Edayadulla ◽  
V. G. Sathe ◽  
...  

Silver nanoparticles were synthesized using solution combustion method with citric acid as fuel. The prepared silver nanoparticles exhibit fcc crystalline structure with particle size of ~50 nm. The morphology and purity of the silver nanoparticles were also studied by high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray analysis (EDX). Surface-enhanced Raman scattering (SERS) spectra of 2,6-dicarbethoxy-3,5-bis(pyridine-3-yl)tetrahydro-1,4-thiazine-1,1-dioxide (DBTD) adsorbed on silver nanoparticles were investigated. Orientation of DBTD on silver nanoparticles has been inferred from normal Raman spectrum (nRs) and SERS spectral feature. The observed spectral feature evidenced that DBTD would adsorb on silver surface with tilted orientation through the lone pair electrons of C–N, C=O, S=O, and pyridine ring. The present investigation has been a model system to deduce the interaction of drugs with DNA.


2013 ◽  
Vol 873 ◽  
pp. 206-210
Author(s):  
Kai Li ◽  
Rao Fu ◽  
Qing Ran Gao ◽  
Ai Wei Tang ◽  
Ying Feng Wang

This paper continues our previous work on preparation of triangular silver nanoparticles. The method proceeds with reaction of silver nitrate with hydrazine hydrate in the presence of polyvinyl pyrrolidone in aqueous solution. Effects of the concentration of PVP on the morphologies of Ag NPs were systematically investigated. The obtained Ag NPs were characterized by transmission electron microscopy and UV-visible spectrophotometer. The results showed that, triangular Ag NPs with edge lengths in the range of 50-200 nm were obtained using PVP as protective agent with lower concentration. As the concentration of PVP increased, spherical Ag NPs with their sizes about 6.2 nm were prepared and triangular Ag NPs were not obtained. The formation mechanism of triangular Ag NPs has been studied. Ostwald ripening is the driving force on the conversion of spherical Ag NPs to triangular Ag NPs in the presence of PVP.


2013 ◽  
Vol 829 ◽  
pp. 152-156 ◽  
Author(s):  
Hamed Sadabadi ◽  
Adeleh Aftabtalab ◽  
Shirzad Zafarian ◽  
Shilpa Chakra ◽  
K. Venkateswara Rao ◽  
...  

Copper oxide nanoparticles have been received attraction due to their unique properties and potential future applications. In present work nanostructure Copper (II) oxide (CuO) spherical nanoparticle synthesized by solution combustion method and the influence of different fuel and condition on the properties of CuO particle was investigated. Crystalline phase and size indicated by applying XRD and particle size distribution studied further using DLS. Scanning electron microscopy (SEM) was used for morphological study and EDAX analysis shows composition of CuO particles. Nanostructure of copper (II) oxide particle studied further by Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) applied for detail study on crystalline structure of particles.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
R. D. Ávila-Avilés ◽  
N. Torres-Gómez ◽  
M. A. Camacho-López ◽  
A. R. Vilchis-Nestor

Abstract Nature provides remarkable examples of mass-produced microscale particles with structures and chemistries optimized by evolution for particular functions. Synthetic chemical tailoring of such sustainable biogenic particles may be used to generate new multifunctional materials. Herein, we report a facile method for the synthesis of hybrid nano/microstructures Ag-Fe3O4 based on Dimorphotheca ecklonis pollen grains as bio-template. Silver nanoparticles was biosynthesized using pollen grains as a reduction and stabilization agent as well as a bio-template promoting the adhesion of silver nanoparticles to pollen surface. Fe3O4 nanoparticles were synthesized by co-precipitation method from FeSO4. Hybrid nano/microstructures Ag-Fe3O4 based on Dimorphotheca ecklonis pollen grains as bio-template were obtained and characterized using Scanning Electron Microscopy and Transmission Electron Microscopy to study the morphology and structure; Energy-Dispersive X-ray Spectroscopy to determine the chemical composition distribution; and Confocal Fluorescence Microscopy to demonstrate the fluorescence properties of hybrid nano-microstructures. Furthermore, these hybrid nano-microstructures have been studied by Surface-Enhanced Raman Scattering (SERS), using methylene blue as a target molecule; the hybrid nano-microstructures have shown 14 times signal amplification.


2018 ◽  
Vol 24 (8) ◽  
pp. 5801-5804
Author(s):  
K. N. Shravana Kumara ◽  
H. P Nagaswarupa ◽  
K. R. Vishnu Mahesh ◽  
M Mylarappa ◽  
S. C Prashantha ◽  
...  

The objective of this work is mainly focused on green synthesis and characterization of MgO nanoparticles by low temperature solution combustion method. The Murraya koenigii (Curry leaves) was used as a reducing agent (as fuel). The average size and crystallinity of nano MgO particles are analyzed by X-ray Diffraction method (PXRD) and accurate morphology was studied using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). From XRD, shows that average particle size of MgO is 40 nm. The synthesized MgO particles used as an efficient catalyst shows rapid color removal and reduction in the concentration of dyes.


The Analyst ◽  
2016 ◽  
Vol 141 (18) ◽  
pp. 5382-5389 ◽  
Author(s):  
Trang H. D. Nguyen ◽  
Peng Zhou ◽  
Azlin Mustapha ◽  
Mengshi Lin

Silver nanoparticles (Ag NPs) are one of the top five engineered nanoparticles that have been used in various products.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Vinod Vellora Thekkae Padil ◽  
Nhung H. A. Nguyen ◽  
Alena Ševců ◽  
Miroslav Černík

Gum karaya (GK), a natural hydrocolloid, was mixed with polyvinyl alcohol (PVA) at different weight ratios and electrospun to produce PVA/GK nanofibers. An 80 : 20 PVA/GK ratio produced the most suitable nanofiber for further testing. Silver nanoparticles (Ag-NPs) were synthesised through chemical reduction of AgNO3(at different concentrations) in the PVA/GK solution, the GK hydroxyl groups being oxidised to carbonyl groups, and Ag+cations reduced to metallic Ag-NPs. These PVA/GK/Ag solutions were then electrospun to produce nanofiber membranes containing Ag-NPs (Ag-MEMs). Membrane morphology and other characteristics were analysed using scanning electron microscopy coupled with energy dispersive X-ray analysis, transmission electron microscopy, and UV-Vis and ATR-FTIR spectroscopy. The antibacterial activity of the Ag-NP solution and Ag-MEM was then investigated against Gram-negativeEscherichia coliandPseudomonas aeruginosaand Gram-positiveStaphylococcus aureus. Our results show that electrospun nanofiber membranes based on natural hydrocolloid, synthetic polymer, and Ag-NPs have many potential uses in medical applications, food packaging, and water treatment.


Applied Nano ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 242-256
Author(s):  
Mimi Liu ◽  
Anjuli Bhandari ◽  
Mujtaba Ali Haqqani Mohammed ◽  
Daniela R. Radu ◽  
Cheng-Yu Lai

Surface-enhanced Raman scattering has developed into a mature analytical technique useful in various applications; however, the reproducible fabrication of a portable SERS substrate with high sensitivity and good uniformity is still an ongoing pursuit. Reported herein is a rapid fabrication method of an inexpensive SERS substrate that enables sub-nanomolar detection of molecular analytes. The SERS substrate is obtained by application of silver nanoparticles (Ag NPs)-based ink in precisely design patterns with the aid of an in-house assembled printer equipped with a user-fillable pen. Finite-difference time-domain (FDTD) simulations show a 155-times Ag NP electric field enhancement for Ag nanoparticle pairs with particle spacing of 2 nm. By comparing the SERS performance of SERS substrate made with different support matrices and fabrication methods, the PET-printed substrate shows optimal performance, with an estimated sensitivity enhancement factor of 107. The quantitative analysis of rhodamine 6G absorbed on optimized SERS substrate exhibits a good linear relationship, with a correlation coefficient (R2) of 0.9998, between the SERS intensity at 610 cm−1 and the concentration in the range of 0.1 nM—1μM. The practical low limit detection of R6G is 10 pM. The optimized SERS substrates show good stability (at least one month) and have been effectively tested in the detection of cancer drugs, including doxorubicin and metvan.


2021 ◽  
Vol 41 (03) ◽  
pp. 393-399
Author(s):  
Parwin Jalal Jalil

Spillage of protoscoleces within hydatid fluid during surgery for hydatid cyst is the main reason for its recurrence. Therefore, to inactivate the protoscoleces, various scolicidal substances have been tested. However, novel and more efficient agents are needed owing to several associated complications. This study focused on the effects of green synthetic Silver Nanoparticles (AgNPs) from Zizyphus spina- christi leaves on Echinococcus granulosus protoscoleces. Also, to evaluate the blood compatibility of Ag NPs. The Ag NPs were identified by ultraviolet-visible (UV-Visible) spectrophotometer, X-ray diffraction (XRD), Scanning electron microscopy imaging, and Energy-dispersive X-ray spectroscopy (EDX). Hydatid fluid was aspirated aseptically from cysts of infected sheep liver. The protoscoleces were exposed to Ag NPs at several concentrations. Also, scanning electron microscopy for ultrastructural changes and in vitro erythrocytes lysis was performed. The Ag NPs were spherical; the particles' size reached 50 nm, and presented a surface plasmon peak around 460 nm. The current study's findings indicated the powerful in vitro scolicidal efficacy of the green biosynthesized AgNPs. Several morphological alterations were observed on the protoscoleces by optical and scanning electron microscopy. Lysis of RBCs at different doses of Ag NPs was significantly (P≤0.05) less than the positive control value, thus proposing its biocompatibility. This work suggests that chemicals like polyphenols present in the extract of Z. spina- christi act as reducing and stabilizers agents to create Ag NPs Nevertheless, further investigations are needed to investigate the Ag NPs scolicidial effects in animal models.


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