Preparation of nano-silver/mesoporous silica composite materials and its antibacterial properties

Objective The traditional Ag⁺ wood antibacterial agents have the problem that Ag⁺ is easy to be oxidized, which leads to its limited antimicrobial durability, and the silver nanoparticles in novel nano-silver antibacterial agent also have the problem of easy aggregation. In order to solve these problems, a novel silver-loaded silica (Ag/MCM-41-NH₂) composite antibacterial material was prepared in this paper.

Method The composite material was prepared by embedding silver ions into the modified carrier and in-situ green reduction to AgNPs. SEM, TEM, adsorption desorption of N₂, XPS, XRD, FTIR and ICP-MS were used to analyze the surface morphology, structure and slow release feature of it. The inhibition zone method and oscillating method were used to analyze the antibacterial properties and antibacterial durability of composite antibacterial agents.

Result The modified MCM-41 was successfully grafted with a large number of –NH₂, which could graft with Ag⁺. In addition, the spherical AgNPs were uniformly loaded inside the MCM-41-NH₂. The results of bacteriostatic test showed that the initial antibacterial rate of Ag⁺/MCM-41-NH₂ and Ag/MCM-41-NH₂ against Staphylococcus aureus and Escherichia coli was over 99.00%. However, the loss rate of Ag⁺ in Ag⁺/MCM-41-NH₂ was 25.00% and its antibacterial rates against S. aureus and E. coli were decreased to 88.75% and 79.10% after 90 d, while the loss rate of Ag⁺ in Ag⁺/MCM-41-NH₂ was 5.10% and its antibacterial rate against S. aureus and E. coli remained at a high level of 98.93% and 96.93%.

Conclusion Ag-NPs can be uniformly dispersed on the carrier MCM-41-NH₂, and the Ag/MCM-41-NH₂ composite antibacterial agent has good antibacterial property and antibacterial durability.