Preparation of Ag/SiO2 nanocomposite and assessment of its antifungal effect on soybean plant (a Vietnamese species DT-26)

Hoai Chau Nguyen, Thi Thuy Nguyen, Trong Hien Dao, Quoc Buu Ngo, Hoang Long Pham and Thi Bich Ngoc Nguyen

Abstract

Soybean crop losses due to fungal diseases are considerable and directly depend on the severity of the disease. The objective of this study was to assess antifungal activity of silver/silica (Ag/SiO₂) nanocomposite against crop pathogenic fungi (Fusarium oxysporium and Rhizoctonia solani) in soybean farming. Firstly, silica particles with a size ranging from 20 to 30 nm were modified with 3-aminopropyl triethoxysilane (APTES) for 2 h. Then these amino acid - functionalized silica particles were exposed to silver ion solution followed by reduction of silver ions with sodium borohydride to form Ag/SiO₂ nanocomposite. The formation of the linkage between APTES and silica particles was confirmed by Fourier transform infrared (FTIR) spectroscopy. The surface plasmon absorption maximum at 400 nm confirmed the nano essence of the silver particles on silica particles. For the seed coating, bentonite from Lam Dong deposit, Vietnam, was used as an encapsulation substance, while carboxymethyl cellulose (CMC) was used as a binding agent. The assessment of fungicidal activity of the Ag/SiO₂ nanocomposite produced showed that this product is effective in inhibition of the pathogenic fungi in soybean plant