scholarly journals SERS Characterization of the Indocyanine-Type Dye IR-820 on Gold and Silver Nanoparticles in the Near Infrared

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Tatiana B. V. Neves ◽  
Gustavo F. S. Andrade

The Raman spectrum of the indocyanine-type dye IR-820 has been assigned for both solid and solution. SERS spectra of IR-820 on both silver and gold nanoparticles suspensions excited at 1064 nm were obtained. AgNPs allowed the detection of the dye through SERS down to 0.1 micromoles per liter; for the AuNPs the lowest concentration of the dye detectable was 10 micromoles per liter. Changes in the SERS relative intensities compared to the Raman spectrum in solution are subtle, mostly due to the preresonance effect of the dye. However, a perpendicular orientation relative to the metallic surface was inferred for the dye on both AgNPs and AuNPs. The easily distinguishable SERS spectra of the dye excited at 1064 nm, together with the high biological compatibility of cyanine dyes, are both indicative that IR-820 could be used as a high-performance probe molecule for SERS.

2020 ◽  
Vol 4 (2) ◽  

Metal nanoparticles possess an extensive scientific and technological significance due to their unique physiochemical properties and their potential applications in different fields like medicine. Silver and gold nanoparticles have shown to have antibacterial and cytotoxic activities. Conventional methods used in the synthesis of the metal nanoparticles involve use of toxic chemicals making them unsuitable for use in medical field. In our continued effort to explore for simple and eco-friendly methods to synthesize the metal nanoparticles, we here describe synthesis and characterization of gold and silver nanoparticles using Gonaderma lucidum, wild non-edible medicinal mushroom. G. lucidum mushroom contain bioactive compounds which can be involved in the reduction, capping and stabilization of the nanoparticles. Antibacterial activity analysis was done on E. coli and S. aureus. The synthesis was done on ultrasonic bath. Characterization of the metal nanoparticles was done by UV-VIS., High Resolution Transmission Electron Microscope (HRTEM) and FTIR. HRTEM analysis showed that both silver and gold nanoparticles were spherical in shape with an average size of 15.82±3.69 nm for silver and 24.73±5.124nm for gold nanoparticles (AuNPs). FTIR analysis showed OH and -C=C- stretching vibrations, an indication of presence of functional groups of biomolecules capping both gold and silver nanoparticles. AgNPs showed inhibition zones of 15.5±0.09mm and 13.3±0.14mm while AuNPs had inhibition zones of 14.510±0.35 and 13.3±0.50mm on E. coli and S. aureus respectively. The findings indicate the potential use of AgNPs and AuNPs in development of drugs in management of pathogenic bacteria.


2021 ◽  
Vol 9 (6) ◽  
pp. 678
Author(s):  
Kaliyamoorthy Kalidasan ◽  
Nabikhan Asmathunisha ◽  
Venugopal Gomathi ◽  
Laurent Dufossé ◽  
Kandasamy Kathiresan

This work deals with the identification of a predominant thraustochytrid strain, the optimization of culture conditions, the synthesis of nanoparticles, and the evaluation of antioxidant and antimicrobial activities in biomass extracts and nanoparticles. Thraustochytrium kinnei was identified as a predominant strain from decomposing mangrove leaves, and its culture conditions were optimized for maximum biomass production of 13.53 g·L−1, with total lipids of 41.33% and DHA of 39.16% of total fatty acids. Furthermore, the strain was shown to synthesize gold and silver nanoparticles in the size ranges of 10–85 nm and 5–90 nm, respectively. Silver nanoparticles exhibited higher total antioxidant and DPPH activities than gold nanoparticles and methanol extract of the strain. The silver nanoparticles showed higher antimicrobial activity than gold nanoparticles and petroleum ether extract of the strain. Thus, Thraustochytrium kinnei is proven to be promising for synthesis of silver nanoparticles with high antioxidant and antimicrobial activity.


Author(s):  
Manikandan Dhayalan ◽  
Michael Immanuel Jesse Denison ◽  
Manikandan Ayyar ◽  
N.N. Gandhi ◽  
Kathiravan Krishnan ◽  
...  

1999 ◽  
Vol 53 (1) ◽  
pp. 86-91 ◽  
Author(s):  
Stewart F. Parker ◽  
Susan M. Tavender ◽  
N. Michael Dixon ◽  
Henryk Herman ◽  
Kenneth P. J. Williams ◽  
...  

2020 ◽  
Vol 42 (3) ◽  
pp. 440-440
Author(s):  
Xin Bin Yang Xin Bin Yang ◽  
Chun Mei Wang Chun Mei Wang ◽  
Yu Huang Yu Huang

Gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) were synthesized by using water-soluble Kaempferol–3′–sulfonate acid sodium (KS) alone as the reducing agent. The UV-vis spectra confirmed the formation of the ks-AuNPs and ks-AgNPs which were stable for up to 3 months without any other stabilizing agents at room temperature. The TEM studies exhibited monodispersed and mainly spherical nanoparticles with the size in the range of 15-30 nm and 20-50 nm for ks-AuNPs and ks-AgNPs, respectively. The XRD revealed crystallinity of nanoparticles. The chemical state of Au and Ag on the surface of nanoparticles was analyzed by XPS. The FTIR analysis indicated that the hydroxyl of KS were responsible for the reduction of Au3+ and Ag+ to ks-AuNPs and ks-AgNPs, respectively. Cytotoxic activity of ks-AuNPs and ks-AgNPs on MCF-7 cells is higher than the KS.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Duhita G. Sant ◽  
Tejal R. Gujarathi ◽  
Shrikant R. Harne ◽  
Sougata Ghosh ◽  
Rohini Kitture ◽  
...  

Development of an ecofriendly, reliable, and rapid process for synthesis of nanoparticles using biological system is an important bulge in nanotechnology. Antioxidant potential and medicinal value of Adiantum philippense L. fascinated us to utilize it for biosynthesis of gold and silver nanoparticles (AuNPs and AgNPs). The current paper reports utility of aqueous extract of A. philippense L. fronds for the green synthesis of AuNPs and AgNPs. Effect of various parameters on synthesis of nanoparticles was monitored by UV-Vis spectrometry. Optimum conditions for AuNPs synthesis were 1 : 1 proportion of original extract at pH 11 and 5 mM tetrachloroauric acid, whereas optimum conditions for AgNPs synthesis were 1 : 1 proportion of original extract at pH 12 and 9 mM silver nitrate. Characterization of nanoparticles was done by TEM, SAED, XRD, EDS, FTIR, and DLS analyses. The results revealed that AuNPs and AgNPs were anisotropic. Monocrystalline AuNPs and polycrystalline AgNPs measured 10 to 18 nm in size. EDS and XRD analyses confirmed the presence of elemental gold and silver. FTIR analysis revealed a possible binding of extract to AuNPs through –NH2 group and to AgNPs through C=C group. These nanoparticles stabilized by a biological capping agent could further be utilized for biomedical applications.


2017 ◽  
Vol 41 (23) ◽  
pp. 14288-14298 ◽  
Author(s):  
Sijo Francis ◽  
Siby Joseph ◽  
Ebey P. Koshy ◽  
Beena Mathew

Phytoreduced nanoparticles have multi-functionalities due to their sustainable origin and biocompatible nature.


Sign in / Sign up

Export Citation Format

Share Document