Applied Science and Convergence Technology 2021; 30(2): 54-61
Published online March 31, 2021
Copyright © The Korean Vacuum Society.
K. Sowmiyaa, K. Aishwaryab, R. Navamathavana,∗, Hak Yong Kimc,∗, and R. Nirmalaa,d,∗
aDepartment of Microbiology, Hindustan College of Arts and Science, University of Madras, Chennai 603103, India
bDivision of Physics, School of Advanced Sciences, Vellore Institute of Technology, Chennai 600127, India
cDepartment of Bio-Info-Nanotechnology Convergence Technology, Jeonbuk National University, Jeonju 54896, Republic of Korea
dDepartment of Biotechnology, Hindustan College of Arts and Science, University of Madras, Chennai 603103, India
We report on silver nanoparticles synthesize with the Corallocarpus epigaeus rhizome extract and their characteristics. The synthesized phy- tochemical compound acts as both a stabilizing and a reducing agent. We systematically characterize the synthesized silver nanoparticles. UV-Vis spectra confirmed the formation of green synthesized silver nanoparticles from the Corallocarpus epigaeus rhizome. Scanning elec- tron microscopy and high-resolution transmission electron microscopy images exhibited indicated spherical and randomly distributed silver nanoparticles. The synthesized nanoparticles of the Corallocarpus epigaeus rhizome aqueous extract showed bacteriostatic activity against Pseu- domonas aeuginosa, Escherichia coli, Proteus mirabilis, Bacillus cereus, and Staphylococcus aureus. The synthesized silver nanoparticles from Corallocarpus epigaeus rhizome aqueous extract displayed fungicidal activity of Mucor species, Aspergillus niger, Aspergillus flavus, and Rhizopus species. Furthermore, the silver nanoparticles exhibited a cytotoxic activity of inhibiting HepG2 cell proliferation in the MTT cytotoxicity test.
Keywords: Corallocarpus epigaeus, UV irradiation, Ag nanoparticles, Biomedical
Metal nanoparticles have been extensively used in numerous recent technological applications [1–3]. Nanoparticles exhibit important optical, electronic, captivating, and catalytic attributes owing to their high surface area to volume ratio, as compared to their bulk [4,5]. In particular, silver nanoparticles are one of the most frequently engineered materials utilized in numerous technological and industrial applications. Several approaches are available for the synthesis of these silver nanoparticles. These approaches include reduction in solutions, thermal decomposition of silver compounds, microwave assisted synthesis, laser mediated synthesis, and the biological reduction method . Among these, plantmediated synthesis of silver nanoparticles is considered a conservational technique . The attractive attributes of silver nanoparticles frequently depend on their size and shape. The morphological properties of less aggregated, small, and spherical-shaped silver nanoparticles afford better performance, which in turn indicates a higher potential for applications . These nanoparticles have been employed to prevent wound infections, and as wound dressing by adding them into topical creams and as antimicrobial agents. They can also be used as anticancer agents [9–11].
Recently, metal nanoparticles obtained from plants and plant-derived materials have gained interest for numerous technological applications [12–16]. This type of synthesis is more adaptable than the microbemediated nanoparticles synthesis process. Synthesized metal nanoparticles originating from plants and plant-derived materials eliminate the need for culture maintenance and are easy to handle. In particular, the green synthesis of silver nanoparticles is more advantageous compared to other methods. This process does not necessitate requirements such as high pressure, energy, temperature, and toxic chemicals [17, 18]. Silver nanoparticles can also be synthesized from other plant parts [19,20]. These metabolites function as bioactive compounds and are capable of acting as both capping and reducing agents. This eliminates the requirement of the addition of any other chemical agents to the synthesized nanoparticles .
In the present study, we synthesized silver nanoparticles with the
The rhizome of
The dust and debris on the collected rhizomes were washed using running tap water followed by distilled water. Figure 1 shows the photograph of
The silver nitrate solution was mixed with the
UV-irradiating synthesis was conducted at a wavelength of 253.7 nm and time intervals of 5, 10, and 15 min. Among these solutions, plant extract at the ratio of 6:4 with 5 mM silver nitrate exhibited dark brown color. The result was obtained in 15 min. The solution was subsequently centrifuged at 12000 rpm for 10 min at 4 °C. The overall yield of the extract was 100 μg/ml, and the experiments were carried out with this yield.
Employing the gold palladium coating method, the samples were coated on a clean glass plate and analyzed. After the preparation, sample plates were examined, and the size and shape of the particles was determined using SEM (TESCAN VEGA3). The silver nanoparticle morphology was assessed using high resolution transmission electron microscopy. The structural characterization of Ag nanoparticles was performed using X-ray diffraction (Rigaku Smart Lab 3kW, Japan). The bonding configuration of the silver nanoparticles was studied using an FTIR spectrometer (Bruker, Germany). The biologically synthesized silver nanoparticles were observed systematically, i.e., reduction of Ag+ ions during different time intervals using the UV-Visible spectrophotometer (Shimadzu, UV-2450). The absorption maximum was recorded before and after the synthesis of the nanoparticles using the
The culture of the test microorganisms (
A sterile swab was moistened with the broth culture, after which it was pressed against the sides of the tubes to remove excess fluids and was swabbed evenly over the MHA medium. After swabbing, the surface was allowed to dry. The prepared filter paper discs were placed in the previously prepared agar plates. To complete contact with the agar surface, each disc was pressed down. They were evenly distributed, such that they were no closer than 24 mm from each other. Each plate was examined after 24 h of incubation at 37 °C. The resulting zones of inhibition were uniformly circular with a confluent lawn of growth. The diameters of the zones and discs with complete inhibition were measured.
HepG2 cells collected from NCCS (National Centre For Cell Science, Pune) were cultivated in Rose well Park Memorial Institute medium (RPMI), supplemented with 10 % fetal bovine serum, penicillin/streptomycin (250 U/ml), gentamycin (100 μg/ml), and amphotericin B (1 mg/ml) from Sigma Chemicals, MO, USA. All cells cultivated were maintained at 37 °C in a humidified atmosphere of 5 % CO2. The cells were allowed to proliferate for more than 24 h before use. The sample concentrations were recorded.
The conventional MTT reduction test was used to measure cell viability, as described previously with slight modifications. In summary, HepG2 cells were seeded at a density of 5 × 103 cells/well in 96-well plates for 24 h, in 200 μl of RPMI with 10 % fetal bovine serum. RPMI containing various concentrations of the test sample was added and incubated for 48 h. Cells were incubated with MTT (10 μl, 5 mg/ml) at 37 °C for 4 h after treatment and then with DMSO at room temperature for 1 h. The 595 nm plates were read on a scanning multi-well spectrophotometer.
Figure 4 shows the SEM images of
Figures 5(a) and 5(b) show the synthesized silver nanoparticles viewed at low and high magnifications via HRTEM. The images obtained using HRTEM show that the synthesized silver nanoparticles have a spherical morphology with smaller sizes (10 - 90 nm). Because the prepared silver nanoparticles were used for HRTEM analysis, we were able to observe the sizes of the silver nanoparticles in the range of 10–90 nm, which differs significantly from SEM observations (as dried materials are used for SEM analysis). The overall morphology of the silver nanoparticles is more clearly observed at a random distribution of the sizes, as shown in the HRTEM images. Figure 5(c) clearly depicts the lattice fringes of the SAED patterns of silver nanoparticles, which confirm the polycrystalline nature of the material. As far as biomedical applications are concerned, the formations are of uniform size and without any agglomeration of Ag nanoparticles.
The XRD patterns of pristine and sample silver nanoparticles are shown in Figs. 6(a) and 6(b), respectively. The diffraction peaks show that the synthesized
Changes in the functional groups were obtained using FTIR spectroscopy. Figure 7 shows the FTIR spectrum of the Ag nanoparticles extracted from plant and pristine plant. The characteristic transmittance spectrum of Ag nanoparticles can thus be assigned. The peak around 500–1700 cm−1 represents the sample synthesized from the plant extract. The peak at approximately 1700 cm−1 (amide I) indicates the presence of silver nanoparticles due to the existing amino group. The appearance of the CH2 groups in the final product is marked by the CH2 transmittance band in the 2000–2250 cm−1 region . The stretching of the –OH group can be obtained through the presence of a broad peak between 3400–3500 cm−1.
UV-Vis spectroscopy is a useful technique for the determination of nanoparticle synthesis. The highest absorption peak was observed for a wavelength of 420–460 nm, representing the characteristic peak for silver nanoparticle synthesis, as shown in Fig. 8.
Figure 11 shows the antifungal activity of
The MTT cytotoxicity test was performed, and the resulting HepG2 cell line images are shown in Fig. 12. The MTT test was utilized for survival determination measurements, and the concentrations required for cell viability and cytotoxicity were determined, as shown in Figs. 13 and 14, respectively. The effect of the samples on the reproduction of HepG2 was expressed as the % cell viability. Tukappa
Our future research plan involves the isolation and evaluation of these active compounds to elucidate the exact mechanism of action. The cytotoxicity activity against HepG2 cells was demonstrated; hence, further studies including assay for apoptosis, DNA damage, and detection of gene expression (real time-PCR) followed by flow cytometry may be carried out to use
The plant rhizomes of