Facile synthesis of silver nanoparticles deposited on a calcium silicate hydrate composite as an efficient bactericidal agent

Abstract

Silver nanoparticles (Ag NPs) have been widely used for the disinfection and prevention of pathogenic bacteria. However, the aggregation and instability of Ag NPs significantly limit their bactericidal activity. As an alternative method, stabilization of Ag NPs on an inorganic biomaterial is a promising strategy. In this study, an inorganic material with good biocompatibility and bioactivity, calcium silicate hydrate (CSH), was employed as the host substance. A facile and efficient method was proposed to produce Ag NPs deposited on a CSH (CSH/Ag) composite. Ag⁺ ions were first embedded into the surface of CSH through ion-exchange and subsequently reduced to Ag NPs by a reducing agent. Due to the high specific surface area and great ion-exchange capacity of CSH, a series of CSH/Ag composites with different silver contents were easily synthesized. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), elemental mapping, X-ray diffraction (XRD), nitrogen sorption/desorption analysis, and inductively coupled plasma-atomic emission spectrometry (ICP-AES) were employed to characterize the synthesized CSH/Ag composites. Moreover, Ag⁺ ions release behaviours from the CSH/Ag composites were investigated and the release profiles showed dose-dependent and long-time sustained release properties. Furthermore, the synthesized CSH/Ag composite displayed good biocompatibility and high antibacterial activities against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Overall, the newly designed CSH/Ag composite is believed to be a promising bactericidal agent in biomedical applications.