Controlled hydrothermal synthesis of Ag nanowires and their antimicrobial properties

Abstract

The therapeutic effect of existing antibacterial agents is weakening as bacterial resistance increases. Therefore, researchers should focus on exploring and developing new antibacterial materials. In this work, Ag nanowires (AgNWs) were synthesized using a hydrothermal method, and the optimal synthesis conditions were determined. The fabricated AgNWs were characterized, and their antibacterial effect was studied. The optimal AgNW synthesis conditions were as follows: reaction temperature of 130 °C, reaction time of 60 min, silver nitrate:trisodium citrate ratio of 1:7.5, and sodium dodecylsulfonate concentration of 1 mM. Under these conditions, the diameter and length of the synthesized AgNWs were approximately 40 ± 5 nm and approximately 10 ± 1.5 μm, respectively. The prepared AgNWs presented good dispersion and a face-centered cubic crystal structure, and nanocrystals preferentially grew along the (111) crystal plane direction. In addition, AgNWs exhibited a good antibacterial effect against Gram-positive (G+) bacteria, namely Staphylococcus aureus and Enterococcus faecalis, and Gram-negative (G-) bacteria, namely Escherichia coli and Klebsiella pneumoniae. The minimum inhibitory concentrations of AgNWs for the aforementioned bacteria strains were 9.38, 18.75, 4.69, and 1.17 μg/mL, respectively. Therefore, AgNWs were more sensitive against G- bacteria than against G+ bacteria. This work provides a good foundation for the use of AgNW as nanomaterial antibacterial agents.