Gold nanoclusters embedded in antimicrobial keyboard covers: life cycle assessment and environmental sustainability

Gold nanoparticles and nanoclusters can be used in a variety of sectors in different applications. Research on new synthesis methods and procedures for their integration into products is flourishing with positive results. This study focuses on the environmental impacts of synthesising cysteine-capped gold nanoclusters [Au 25 (Cys) 18 ] and their integration in silicone keyboard covers. The final product presents an antibactericidal activity that could make it suitable for use in hospital wards to tackle the cross-transmission of pathogens. Life cycle assessment (LCA) methodology is used here to analyse and compare the environmental impacts of antimicrobial keyboard covers against current procedures for cleaning keyboards in hospitals using gloves and alcohol wipes (70%). Furthermore, results have been compared with the normalisation factors based on two reference systems: global emissions and carrying-capacity values. Whilst the first reference system indicates the contribution of a production system relative to the global emissions; the latter provides an indication of the absolute environmental sustainability of the system evaluated. This study shows that adopting an antimicrobial keyboard cover results in lower environmental impacts than using gloves and alcohol wipes, almost for all the impact categories considered. Life cycle assessment can help quantify the environmental impacts of products embedding nanoparticles. Furthermore, it can support the evaluation of absolute environmental sustainability by employing carrying-capacity normalization factors.