Nano-scaled advanced materials for antimicrobial applications – mechanistic insight, functional performance measures, and potentials towards sustainability and circularity

About 13.7 million people died worldwide from infectious diseases in 2019 which accounts for one fifth of all annual deaths. Infectious diseases are caused by microbes (i.e. bacteria, fungi, viruses) predominantly targeting the respiratory system, bloodstream, gastrointestinal region and urinary tract, which can lead to severe health problems. Microbes can naturally adapt and develop antimicrobial resistance to conventional medication. Health systems are concerned by the overuse of antibiotics in the medical, agricultural, and food industry. This leads to bacterial multidrug resistance, causing more than half a million deaths annually. In consequence, research and innovation have focused on nano-scaled advanced materials to explore their potential to reinforce antimicrobial treatments. Advanced materials are complex composites that achieve superior, combined functionalities with an optimized safety, sustainability, and circularity profile. They often contain nano-scaled materials, which are highly versatile, organic, or inorganic materials that can adopt different sizes, compositions, topographies, and surface modifications. All these properties need to be carefully defined using physicochemical characterization techniques and should be considered when selecting the most efficient nanomaterials against widespread microbes. In this review, we cover (i) potential candidates of engineered nanomaterials, their physicochemical characteristics, and demonstrate their efficacy in antimicrobial action; (ii) the mechanisms of action against microbes specific to nanomaterials; (iii) well-established methods and highlight methodological advancements; (iv) the potential improvements in sustainability and circularity and (v) the current and future fields of application and ongoing development in the medical, agricultural, high-tech, textile, and food industry. For the first time, nano-scaled advanced materials produced by green synthesis methods are discussed in respect to their gain in sustainability and circularity and a comprehensive set of methodologies for safety, sustainability, and circularity assessment are described in detail.