scholarly journals Sol–Gel and Electrospinning Synthesis of Silica–Hydroxyapatite–Silver Nanofibers for SEIRAS and SERS

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 910
Author(s):  
Fernando Soto-Nieto ◽  
Rurik Farías ◽  
Simón Yobanny Reyes-López

Surface-enhanced Raman spectroscopy (SERS) and Surface-enhanced infrared absorption spectroscopy (SEIRAS) are both novel techniques favored by the excitation of surface plasmons onto metal nanostructures. The light emitted from the metal surface couples with the vibrational transitions of molecules in proximity, enhancing its spectral response and leading to more sensitive and effective spectroscopic analysis. The absence of inexpensive and reproducible substrates is among the major impediments to the accurate implementation and optimal performance of the technique. The development of a low-cost active substrate based on silica–hydroxyapatite through sol–gel synthesis and electrospinning is addressed in the present study. Fibers of 512 ± 199 nm diameter were produced after sintering at 1150 °C on the electrospun mats. The fibers are fixed to an indium tin oxide (ITO) glass base for electrodeposition with 10 and 20 mM AgNO3 at 1.5 and 3.3 V at different time periods. Electrodeposition produced silver nanorods and nanocubes on the fibers. The SERS and SEIRAS activity of each one of the nine supports was tested using pyridine 1 nM, comparing it with the spectrum of pyridine 1 mM. An enhancement factor of 2.01 × 106 for the band at 3335 cm−1 was obtained during a SEIRAS essay for the support doped for 2 min at 3.3 V with 10 mM silver nitrate solution. The highest SERS enhancement factor was 3.46 × 108, for the band at 1567 cm−1 in the substrate doped for 5 min at 1.5 V with silver nitrate solution at 10 mM. After testing both samples with 10−4 M violet crystal solution, no SERS enhancement factor was found, but higher band resolution in the spectra was observed.

2020 ◽  
Vol 8 (46) ◽  
pp. 16513-16519
Author(s):  
Eleonora Cara ◽  
Luisa Mandrile ◽  
Alessio Sacco ◽  
Andrea M. Giovannozzi ◽  
Andrea M. Rossi ◽  
...  

Determination of the SERS enhancement factor through the challenging measurement of the molecular surface density by reference-free X-ray fluorescence.


2020 ◽  
Vol 1010 ◽  
pp. 397-404
Author(s):  
Kamrosni Abdul Razak ◽  
Dewi Suriyani Che Halin ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Azliza Azani ◽  
Mohd Arif Anuar Mohd Salleh ◽  
...  

Ag/TiO2 thin film was prepared by the sol-gel method through the hydrolysis of titanium tetraisopropoxide and silver nitrate solution. Spin coating method was used to get uniform film on ITO glass substrate followed by annealing process for 1 hour. After that, all the samples were characterised using GIXRD and FESEM and undergone water contact angle test and MB degradation. Silver ion concentrations were varied to observe the effect on crystalline state, morphology, wettability and photocatalytic properties. The results showed that Ag/TiO2 thin film was in anatase phase and it could degrade nearly 70% of methylene blue after 150 min illumination. The formed Ag/TiO2 thin film has excellent self-cleaning property with compact, continuous, smooth, and good hydrophilicity property.


2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Nathan D. Israelsen ◽  
Cynthia Hanson ◽  
Elizabeth Vargis

Raman spectroscopy has enabled researchers to map the specific chemical makeup of surfaces, solutions, and even cells. However, the inherent insensitivity of the technique makes it difficult to use and statistically complicated. When Raman active molecules are near gold or silver nanoparticles, the Raman intensity is significantly amplified. This phenomenon is referred to as surface-enhanced Raman spectroscopy (SERS). The extent of SERS enhancement is due to a variety of factors such as nanoparticle size, shape, material, and configuration. The choice of Raman reporters and protective coatings will also influence SERS enhancement. This review provides an introduction to how these factors influence signal enhancement and how to optimize them during synthesis of SERS nanoparticles.


2008 ◽  
Vol 37 (8) ◽  
pp. 818-819 ◽  
Author(s):  
Yoshiko Miura ◽  
Kazuko Yui ◽  
Hiroshi Uchida ◽  
Kiyoshi Itatani ◽  
Seiichiro Koda

2018 ◽  
Vol 772 ◽  
pp. 73-77
Author(s):  
Ruelson S. Solidum ◽  
Arnold C. Alguno ◽  
Rey Capangpangan

We report on the green synthesis of silver nanoparticles utilizing theP.purpureumleaf extract. Controlling the surface plasmon absorption of silver nanoparticles was achieved by regulating the amount of extract concentration and the molarity of silver nitrate solution. The surface plasmon absorption peak is found at around 430nm. The surface plasmon absorption peak have shifted to lower wavelength as the amount of extract is increased, while plasmon absorption peak shifts on a higher wavelength as the concentration of silver nitrate is increased before it stabilized at 430nm. This can be explained in terms of the available nucleation sites promoted by the plant extract as well as the available silver ions present in silver nitrate solution.


1902 ◽  
Vol 23 ◽  
pp. 163-168 ◽  
Author(s):  
Hugh Marshall

Although the action of potassium persulphate on silver nitrate solution was one of the first persulphate reactions observed (vol. xviii. p. 64), I had not until lately paid any special attention to the behaviour of the ammonium salt in this respect. It appears, however, that in the latter case there are additional actions of great interest, not possible with the potassium salt. A general description of these will be given now, but there are still some points deserving of further investigation.


2021 ◽  
Vol 13 (1) ◽  
pp. 21-30
Author(s):  
O.K. Sharutina ◽  

By mixing solutions of tris(2-methoxy-5-bromophenyl)antimony and silver nitrate in a methanol : acetonitrile mixture (1:1 vol.), nitrato-O,O'-(acetonitrile)[tris(2-methoxy-5-bromophenyl)antimony]silver complex with the general formula [(C6H3ОMe-2-Br-5)3SbAg(μ2-NO3)(Ме3CN)]2•2[(C6H3ОMe-2-Br-5)3SbAgNO3(Ме3CN)] (1) has been obtained. An addition of silver nitrate solution in the methanol : acetonitrile mixture to the tris(2-methoxy-5-bromophenyl)antimony dioxane solution has led to the formation of a small amount of dark crystals of the ionic complex [(2-MeО-5-Br-C6H3)3SbAg(H2O)Sb(C6H3Br-5-OMe-2)3]+[(2-MeО-5-Br-C6H3)3SbAg(m-NO3)3 AgSb(C6H3Br-5-OMe-2)3]-×3C4H8O2 (2). Complexes 1 and 2 have been characterized by IR spectroscopy, and their structures have been determined by X-ray diffraction analysis. The IR spectra of complexes 1 and 2 contain the bands characterizing the Sb-O, Sb-C, С≡N-, and NO3-group band vibrations. X-ray diffraction analysis of the complexes has been carried out on an automatic four-circle D8 Quest Bruker diffractometer (МоКα radiation, λ = 0.71073 Å, graphite monochromator) at 293 K. Crystallographic characteristics of 1: triclinic, P-1 space group, a = 9.32(3), b = 17.50(7), c = 17.97(5) Å, a = 97.56(14), β = 92.90(19), g = 99.45(19) grad., V = 2859(16) Å3, Z = 2, rcalc = 2.069 g/cm3, 2: monoclinic, С2/с space group, a = 17.417(14), b = 21.041(15), c = 32.01(2) Å, a = 90, β = 97.79(3), g = 90 grad., V = 11624(15) Å3, Z = 4, rcalc = 2.006 g/cm3. In the monomeric and dimeric molecules of crystal 1, nitrate ligands are chelating and bridging, respectively. In the cation of complex 2, the silver atom is bonded to two antimony ligands, the third coordination site is occupied by a water molecule. In the dimeric anion there are one antimony ligand and three bridging nitrate groups surrounding each silver atom.


2018 ◽  
Vol 18 (3) ◽  
pp. 421 ◽  
Author(s):  
Dian Susanthy ◽  
Sri Juari Santosa ◽  
Eko Sri Kunarti

A study to examine the performance of p-aminobenzoic acid as both reducing agent for silver nitrate to silver nanoparticles (AgNPs) and stabilizing agent for the formed AgNPs has been done. The synthesis of AgNPs was performed by mixing silver nitrate solution as precursor with p-aminobenzoic acid solution and heating it in a boiling water bath. After the solution turned to yellow, the reaction stopped by cooling it in tap water. The formed AgNPs were analyzed by using UV-Vis spectrophotometry to evaluate their SPR absorption in wavelength range of 400–500 nm. The synthesis process was highly depend on the pH, reaction time, and mole ratios of the reactants. The synthesis only occur in pH 11 and at reaction time 30 min, the particle size of the formed AgNPs was 12 ± 7 nm. Longer reaction time increased the reducing performance of p-aminobenzoic acid in AgNPs synthesis but decreased its stabilizing performance. The increase of silver nitrate amount relative to p-aminobenzoic acid in the synthesis increased the reducing and stabilizing performance of p-aminobenzoic acid and the optimum mole ratio between AgNO3 and p-aminobenzoic acid was 5:100 (AgNO3 to p-aminobenzoic acid).


2016 ◽  
Vol 15 (05n06) ◽  
pp. 1660001 ◽  
Author(s):  
V. P. Manjamadha ◽  
Karuppan Muthukumar

The current work elucidates the utilization of biowaste as a valuable reducing agent for the synthesis of silver nanoparticles. In this study, the wastewater generated during the alkaline pretreatment of lignocellulosic wastes (APLW) was used as a bioreductant to reduce silver nitrate under room temperature. Synthesis of stable silver nanoparticles (AgNPs) was achieved rapidly on addition of APLW into the silver nitrate solution (1[Formula: see text]mM). The morphological characterization of AgNPs was performed using field emission scanning electron microscopy (FESEM). The micrograph clearly depicted the presence of spherical AgNPs. The presence of elemental silver along with biomoilties was determined using energy dispersive X-ray spectroscopy (EDAX) analysis. The X-ray diffraction (XRD) study proved the crystalline form of stable AgNPs. The AgNPs exhibited excellent antibacterial performance against Gram negative organism. The immediate bioreduction of silver ions using APLW was well illustrated in the present study. Thus, APLW serve as an alternative source for reducing agents instead of utilizing valuable medicinal plants for nanoparticles synthesis.


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