Biosynthesis of Silver and Gold Nanoparticles Using Aqueous Extract from Crinum latifolium Leaf and Their Applications Forward Antibacterial Effect and Wastewater Treatment

Hindawi Journal of Nanomaterials Volume 2019, Article ID 8385935, 14 pages https://doi.org/10.1155/2019/8385935 Research Article Biosynthesis of Silver and Gold Nanoparticles Using Aqueous Extract from Crinum latifolium Leaf and Their Applications Forward Antibacterial Effect and Wastewater Treatment Thanh-Truc Vo,1 Thi Thanh-Ngan Nguyen,2,3 Thi Thanh-Tam Huynh,3 Thi Thuy-Trang Vo,4 Thi Thuy-Nhung Nguyen,4 Dinh-Truong Nguyen,4 Van-Su Dang,5 Chi-Hien Dang,1,3 and Thanh-Danh Nguyen 2,3 1 Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam 2 Institute of Research and Development, Duy Tan University, Da Nang, Vietnam 3 Institute of Chemical Technology, Vietnam Academy of Science and Technology, 1 Mac Dinh Chi Street, District 1, Ho Chi Minh City, Vietnam 4 School of Biotechnology, Tan Tao University, Long An, Vietnam 5 Department of Chemical Technology, Ho Chi Minh City University of Food Industry, Ho Chi Minh City, Vietnam Correspondence should be addressed to Thanh-Danh Nguyen; Received 13 March 2019; Revised 14 May 2019; Accepted 20 August 2019; Published 15 September 2019 Academic Editor: Ana Espinosa Copyright © 2019 Thanh-Truc Vo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Crinum latifolium (CL) leaf is a source of various biologically active compounds such as alkaloid and phenolic compounds, which exhibit anti-inflammatory, antitumor, and antimicrobial effects. In the purpose of expanding applications for the field of bionanotechnology, we report biosynthesis of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) by using aqueous extract from C. latifolium leaf and explore antibacterial activity and catalytic performance for degradation of pollutants. The formation of CL-AgNPs and CL-AuNPs is confirmed and optimized by UV-visible spectroscopy with surface plasmon resonance (SPR) peaks at around 402 and 539 nm, respectively. The spherical CL-AgNPs have an average diameter of 20.5 nm and the multishaped CL-AuNPs possess an average size of 17.6 nm. The actions of four bacterial strains were strongly inhibited by using the CL-AgNPs. Furthermore, the biosynthesized metallic nanoparticles (MNPs) exhibited the excellent catalytic degradation performance of pollutants. 1. Introduction There are increased interests in the fabrication of MNPs due to their numerous applications. MNPs are well known as molecules acting in biomaterials, imaging, catalyst, and electrochemical applications [1–6]. Among them, AgNPs and AuNPs are the most promising owing to their physiochemical properties which significantly depend on the size and shape. In the traditional synthesis of AgNPs and AuNPs, reducing agents such as sodium borohydride and hydrazine and capping agents are usually required to maintain the size and shape of MNPs. It reveals many disadvantages including expensive cost and harmfulness towards the environment and biological framework. Alternative syntheses like using microorganisms [7] and enzymes [8] have adopted an ecofriendly approach that reduces the chemical agents, which are potentially hazardous to the environment and human health. Among them, the approach using plant extracts for the synthesis of MNPs is over other biological processes because it offers significant advantages such as lower cost of production, low toxicity, and large-scale synthesis without involving high pressure and energy conditions [9–11]. Although the mechanism of MNP biosynthesis by plant extracts is not yet completely understood, the components 2 such as phenolics, terpenoids, glycosides, alkaloids, and proteins were mainly responsible for reduction and stabilization of biosynthesized MNPs [12, 13]. At the nanoscale, the metals provide many highly active uncoordinated sites because the number of active atoms on the surface is much higher than that in the core [14]. Therefore, MNPs were widely used within catalysis of organic reactions such as cross-coupling and degradation of pollutant dyes. Many recent studies showed that the biosynthesized MNPs have been used effectively for degradation of organic dye pollutants in aqueous medium [15, 16]. It should be noted that the catalytic activity of MNPs strongly depends on the reductants and the capping agents which are responsible to prevent the agglomeration [17]. C. latifolium, a herbaceous perennial flowering plant in the amaryllis family, grows naturally in Asia, from India through Southeast Asia to south China. It has been well known as Vietnamese traditional medicine for the management of allergic disorders and tumor diseases. Its extracts have exhibited various bioactivities such as antitumor, antiviral, and antibacterial effects [18, 19]. C. latifolium is rich in alkaloid, glucoside, and flavonoid content that could be an excellent source to synthesize AgNPs and AuNPs [20–22]. In this study, we have synthesized and characterized AgNPs and AuNPs using aqueous extract of C. latifolium leaf. The optimized MNPs were studied for antibacterial potential and catalytic degradation of pollutants in aqueous medium. 2. Experimental 2.1. Materials. Silver nitrate (AgNO3), hydrogen tetrachloroaurate (III) hydrate (HAuCl4.3H2O), sodium tetrahydridoborate (NaBH4), 4-nitrophenol (4-NP), methyl orange (MO), and rhodamine B (RhB) were purchased from Acros (Belgium). C. latifolium leaves were provided by Khai Minh Macrobiotics (Ho Chi Minh City). 2.2. Plant Extract Preparation. The C. latifolium leaves were dried in air atmosphere and finely grinded up with a size of 1-2 mm by using an electronic blender. The resulting powder (10 g) was refluxed with distilled water (100 mL) for 1 h. The mixture was filtered, and the brown filtrate was storable in the refrigerator at 4°C for further studies. 2.3. Biosynthesis and Optimization of Silver and Gold Nanoparticles. The C. latifolium extract was placed in solutions of Ag+ or Au3+ ions under stirring in a dark condition at 1200 rpm. The formation of MNPs was clearly observed by changing in the color. Optimization of reaction parameters including concentration of metallic ions (0.5, 1.0, 1.5, and 2.0 mM), the reaction temperature (in range of 30-120°C), and the reaction time (180 min) was explored through measurement of UV-Vis spectra from a range of 200 to 800 nm. Reduction of ions Ag+ and Au3+ by the plant extract induced increase of absorbance at the peaks of around 400 nm and 540 nm, respectively. For further studies, the CLAgNPs and CL-AuNPs were biosynthesized in the optimized conditions. The solid MNPs were obtained by centrifugation at 10000 rpm for 10 min and washed thrice with water to Journal of Nanomaterials remove metallic ions and the impurities. Finally, the dried powder of MNPs was obtained after heating overnight at 90°C in an oven. 2.4. Physicochem (...truncated)