Design Of Smart Antimicrobial Materials Based On Silver-Silica Nanocapsules

Silver nanoparticles have been commonly used as an antibacterial agent and are often delivered in a burst release manner to the site of infection. However, a drawback of this release mode is the limited lasting duration of the antibacterial properties of the particles. Hence, in order to achieve a more effective and sustained protection against bacteria growth, this project aims to design and create smart antimicrobial materials based on silver-silica nanocapsules that can respond to an acidic environment to release Ag+ ions in a targeted, slow and sustained manner. In this project, the as-synthesized silica-silver nanocapsules were found to exhibit excellent colloidal stability, thus allowing for a homogenous distribution within different polymer matrix materials. Explored applications include the incorporation of the silver-silica nanocapsules into F127 hydrogel and poly(vinyl alcohol) (PVA) film so as to develop antibacterial biomaterials that can effectively prevent bacteria growth for a sustained period of time. In subsequent proof-of-concept studies, both the F127 hydrogel and PVA film were able to respond to acidic conditions for a gradual release of Ag+ ions. Interestingly, the as-released Ag+ ions from the PVA film were effectively entrapped within the polymer matrix, thereby demonstrating their promising potential to sterilize absorbed fluid from wound sites when applied as a wound dressing. On the other hand, the F127 hydrogel exhibited a slow and sustained release of Ag+ ions into the surrounding environment, hence affirming their capacity for topical administration in the form of lotions or creams for antibacterial purposes.