Research Article - (2022) Volume 11, Issue 3
Received: 01-Feb-2022, Manuscript No. JME-22-57012;
Editor assigned: 04-Feb-2022, Pre QC No. JME-22-57012;
Reviewed: 18-Feb-2022, QC No. JME-22-57012;
Revised: 04-Apr-2022, Manuscript No. JME-22-57012;
Published:
12-Apr-2022
, DOI: 10.37421/ 2169-0022.2022.11.12
Citation: Patriciaa AGJ. "An Investigation of Novel Nano Material Silver Nano Dots Synthesis and Characterization Using Simple Sugar Fructose." J Material Sci Eng 11 (2022) : 012.
Copyright: © 2022 Patriciaa AGJ. This is an open-access article distributed under the terms of the creative commons attribution license which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.
Silver nano dots are new and smart materials for application in medical field. Their sizes are in the range of <=10 nm and have unique structural, chemical, physical properties which help in molecular diagnostics, in therapies, in devices used in medical procedures. In this report we present the chemical process in which the silver nano dots are synthesized using a simple ingredient fructose as reducing which is a less expensive and is a rapid phase method. It is a very feasible method to harvest silver nano dots in the lab at a very rapid pace than the conventional methods and without toxic side effects. The size of the silver nano dots were found to match the size of biological molecules and exhibited unique properties which can find a wide array of applications in the field of medicine and industrial electronics. UVVIS study, XRD analysis, FTIR studies and TEM analysis was done to establish the fact that silver nano dots can be synthesized using simple chemical sugar like fructose. Based on the size of the silver nano dots created in the lab and their ability to penetrate the blood brain barrier in the human system they can be applied for diagnostic and therapeutic purposes.
Silver nano dots • Fructose • Surface plasmon resonance • Nano medicine • Medical applications
Nanotechnology is manipulation of matter on an atomic, molecular, and supra molecular scale with at least one dimension sized from 1 to 100 nano meters [1-5]. This definition reflects the fact that quantum mechanical effects are important at this quantum realm scale. Nanotechnology has arisen as a key player in the field of nano medicine [6-10]. A number of new and novel methods are used to fabricate silver nano particles. Each methodology is resulting in a variety of sizes and final products. In this article, we discuss how pure silver nano particles were created via chemical reduction synthesis which is an easy and simple chemical procedure [11-15]. The prepared silver nano dot samples had been examined under UV-VIS, XRD, TEM analytical methods of optical absorption spectroscopy. The silver nano dots created by the above method are compatible for medical application with zero chemical toxicity on application and without environment issues [16-22]. The silver nano dots are ecofriendly and their sizes match the biological molecule sizes [22-24].
Synthesis of silver nano dots
All the analytical grade chemicals used for synthesis were purchased from Sigma Aldrich. Silver nano dots of uniform sizes were prepared by the reduction of silver ions using the simple monosaccharide fructose. In this synthesis, fructose solution was prepared by mixing 0.0050 grams of fructose in 50 ml of de-ionized water taken in a conical flask and 0.001 grams of PVA was added. The Erlenmeyer conical flask was stirred by keeping it on a magnetic stirrer. Then 0.0010 grams of silver nitrate (1 ml of 0.1% AgNO3 aqueous solution- 0.01 M solution) was added to the solution in the flask drop wise regularly. After adding the metallic precursor solution, colour of the solution changed into dark brown within 30 minutes duration as shown in Figure 1. The room temperature was 23°C during this process and the prepared solution.
Figure 1. Silver undergoes chemical reduction.
Was stable for days without decomposition. The colour change indicates the reduction of silver ions and the formation of silver nano dots.
Silver nano particles of the sizes of 10-20 nm match the sizes of biological molecules and hence find applications in medicine for diagnostic and therapeutic purposes. UV-Vis studies were performed in a Shimadzu UV-2600 PC spectro-photometer. Powder XRD analysis of the synthesized silver nanodots was done using Cu-Kα X-rays with wavelength (λ)=1.54056 Å. The surface morphology was analyzed in TEM (transmission electron microscopy). Functional groups were analyzed by FT-IR spectrometer using Ag nano dots KBr pellet.
UV-VIS absorption study
UV-VIS spectroscopy is one of the most widely used for structural characterization of silver nano particles. The nano dot nature of the sample can be identified from the UV-VIS spectra of the solutions. The UV-VIS absorption spectra of the silver nano particle were examined. The absorption peak was obtained at 417 nm.
The Figure 2 shows the UV spectra in the range 350 nm-550 nm. The silver nano dots exhibit an intense absorption peak due to surface plasmon resonance. The absorption band is in the visible light region. The plasmon peak was obtained at 417 nm.
Figure 2. UV-Vis absorption spectrum of silver nanodots shows the SPR peak.
The relationship between particle size and SPR of the UV-Vis absorption spectrum supports for the particle size calculation.
XRD Study
Powder X-ray diffraction analysis of the synthesized sample is shown in Figure 3. It confirms the formation of silver nanodots. The diffraction peaks are observed at 2 θ values of 38.3°, 44.3°, 64.6° and 77.6°. These peaks are corresponding to the (111), (200), (220) and (311) crystalline planes of face cantered cubic (fcc) silver. Absence of peak related to any material other than Ag indicates the purity of the sample. Generally, (111) reflection of FCC materials has high intense peak.
Likewise, in the powder XRD of the sample, the (111) reflection (2 θ value 38.3°) has the most intense peak which is also noted. The observed peaks were compared with the standard silver of Joint Committee on Powder Diffraction Standards (JCPDS), silver file No. 04–0783. The most intense peak of JCPDS located at 2 θ value of 38.11°. The comparison agrees that the resultant particles are FCC silver nano dots.
Figure 3. Powder XRD analysis confirms the silver nanodots (with FCC structure).
The Miller indices (hkl) were assigned to each peak. The miller indices reveal the FCC structure of Ag nano dots (Table 1).
| 2 θ of the intense peak (deg) | (hkl) | FWHM of intense peak in radian | Size of the particle nm | d-spacing mm |
|---|---|---|---|---|
| 38.3 | (111) | 0.0275 | 5.3 | 0.2338 |
| 44.3 | (200) | 0.0183 | 8.2 | 0.2039 |
| 64.6 | (220) | 0.0321 | 5.1 | 0.1444 |
| 77.6 | (311) | 0.0238 | 6.5 | 0.1224 |
Table 1. The particle size of silver nano dots.
The XRD peaks are broad in nature due to the size reduction i.e. nano size of the particles. The particle size and interplanar spacing (d-spacing) were calculated from the most intense peak at 2 θ Cos θ value 38.3° with hkl (111). For these calculations, Debye–Scherrer formula and Bragg’s Law presented in equations (1) and (2) were applied respectively.
D=0.9 λ/W Cos θ ……………………………… (1)
Where D is particle size, 0.9 is Scherrer’s constant, λ is X-ray wavelength (1.5406 Å), W is FWHM (Full Width at Half Maximum) of the peak located at 2 θ = 38.3° and θ is Bragg’s angle of diffraction. The observed θ value in radian is 0.023.
The inter planar spacing (d-spacing) was calculated using Bragg’s Law:
2 d sin θ=n λ……………………………… (2)
Where, d is d spacing and n=1. The particle size of the sample is 6 nm and the d-spacing is 2.34 Å. The d-spacing value related to the peak (111) of JCPDS file: 04-0783 is 2.3590 Å. It is observed that d-spacing value of the sample agrees with JCPDS. The powder XRD results confirm that the synthesized material is silver nano dots.
FT-IR analysis of silver nano dots
FT-IR analysis can be called as the finger print analysis. From this analysis, the elements involved in a synthesis can be traced. This analysis was done to understand the functional groups and formation mechanism (reduction and stabilizing) of Ag nano dots. It was examined that the interactions between the precursor salt (AgNO3), fructose molecules and PVA stabilizing agent. The FT-IR spectrum related to Ag nano dots is shown in Figure 4.
Figure 4. FTIR functional groups analyses of Ag nano dots synthesized by fructose molecules.
The peak details are enumerated in below in Table 2.
| Frequency Range (cm-1) | Absorption (cm-1) | Appearance of Peak | Group | Compound Class |
|---|---|---|---|---|
| 515-690 | 664 | Strong | C-Br stretching | Halo Compound |
| 1050-1085 | 1080 | Strong | C-O stretching | Alcohol |
| 1395-1440 | 1437 | Medium | O-H bending | Carboxylic acid |
| 1600-1650 | 1625 | Medium | C=C stretching | Alkene |
| 2000-2400 | 2365 | Weak | O=C=O stretching | carbon dioxide |
| 700-3200 | 2923 | Weak, broad | O-H stretching | Alcohol |
| 3200-3550 | 3432 | Strong, broad | O-H stretching | Alcohol |
Table 2. FTIR functional group analysis.
It shows the absorption peaks at wave numbers 3432, 2923, 2365, 1625, 1437, 1080 and 664 cm-1.
The peak observed at 3440 cm-1 are due to O-H stretching and deformation. It indicates the absorption of water on the metallic surface. Also, the O-H stretching on the large peak of 3400 cm-1 indicates the intra-molecular and inter-molecular hydrogen bonds. The peaks at 1600 cm-1 and 3400 cm-1 are confirmation for water and hydroxyl groups absorbed by the surface. The absorption peak at 1625 cm-1 indicates the presence of NO2. It may be from the AgNO3 solution which was utilized as metal precursor during the synthesis process of Ag nano dots. Strong interaction in between water and silver surface is the reason for the O-H stretching mode at 2923 cm-1 peak. Absence of COOH functional group supports for the strong luminescence emission.
TEM (Transmission Electron Microscopy) analysis reveals the accurate data about the average size, shape and size distribution of the synthesized nano particles. The TEM image of the synthesized silver nano dots are shown below in Figure 5. It is observed from the TEM analysis that the silver nano dots are in uniform spherical shape. Approximate size of a silver nano dot is 6 nm. Size of the silver nano dots estimated by both TEM and XRD analyses are in good agreement.
Figure 5. TEM image of silver nano dots of sizes 10 nm.
Every nano dot has been detached from each other and stands alone separately. This analysis reveals that the formation and size distribution of silver nano dots is fairly and evenly. It exhibits the thin layer of PVA coating on the silver nano dots. This polymer coating prevents the agglomeration/aggregation of silver nano dots that leads to their protection and stabilization. Also, it supports to enhance the anti-microbial activities of the silver nano dots.
In conclusion, we introduce a simple, fast, and economical method to synthesize silver nano dots. This method provides a clean, nontoxic and ecofriendly and efficient route for the synthesis of nano dots with tunable particle size, at room temperature conditions. There is no need to use high pressure, energy, temperature, toxic chemicals, downstream processing etc. Also the handling of the nano particles is also much easier than other methods. Nanotechnology wise, this is a significant advancement to synthesize silver nano dots. The synthesized Silver nano dots are in spherical shape with particle size of 10 nm. Their characterizations have been successfully done using the UV-VIS, spectra XRD analysis, FTIR and TEM studies exhibit the nano nature of the prepared samples and justify the purpose of this study. So we conclude that silver nano dots can be harvested at the lab using low cost, eco friendly methods and materials like fructose. It is a rapid and convenient method and can find a variety of nano medicinal applications.
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