Improved Synthesis of Ag/SiO₂ Colloidal Nanocomposites and Their Antibacterial Activity Against Ralstonia solanacearum 15

• Published in: Journal of nanoscience and nanotechnology Vol. 21; no. 3; p. 1598
• Main Authors: Pham, Ngoc Bao Tri, Le, Vu Khanh Trang, Bui, Thi Thu Thao, Phan, Nguyen Gia Linh, Tran, Quoc Vinh, Nguyen, Minh Ly, Dang, Vinh Quang, Nguyen, Thanh Tam, Vo, Thi Ngoc Ha, Tran, Cong Khanh
• Format: Journal Article
• Language: English
• Published: United States 01.03.2021
• ISSN: 1533-4899
• DOI: 10.1166/jnn.2021.19021

Ag/SiO₂ colloidal nanocomposites (NCs) were prepared through the semi-continuous chemical reduction of silver ions on a silica surface; NaBH4 was used as a primary reducing agent, while carboxymethyl cellulose (CMC) served as a secondary reductant and a stabilizer at low temperature. Silver nanoparticles (AgNPs) of an average diameter of 3.89±0.18 nm were uniformly and densely dispersed on the SiO₂ surface, forming 218.6-nm-sized Ag/SiO₂ NCs. The zeta potential of the Ag/SiO₂ NCs (-92.6 mV) was more negative than that of silica (-24 mV), indicating their high long-term stability. Furthermore, their proposed formation mechanism was confirmed via Fourier transform infrared spectroscopy. Then, the bactericidal effect of the Ag/SiO₂ was evaluated based on their minimal inhibitory concentration (MIC) against 15 ( 15); it was 62.5 ppm, much lower than that of conventional AgNPs (500 ppm). Therefore, these highly stable Ag/SiO₂ colloidal NCs with more effective antibacterial activity than conventional AgNPs are a promising nanopesticide in agriculture.