Nanoengineered antiviral coatings and air filtration systems: Innovations and challenges in the post-COVID landscape

The COVID-19 pandemic triggered an unprecedented surge in the development of nanoengineered antiviral materials designed to mitigate viral transmission through surfaces and aerosols. This review systematically examines the evolution of antiviral coatings and air filtration systems that incorporate nanomaterials, including silver (Ag), copper oxide (CuO), titanium dioxide (TiO 2 ), and zinc oxide (ZnO). It explores the mechanisms of viral inactivation, ranging from reactive oxygen species (ROS) generation to surface charge interactions, alongside recent breakthroughs in smart, self-cleaning, and reusable surface technologies. The review further discusses the integration of nanomaterials into HVAC filters, face masks, and air purification devices, with a focus on enhancing particle capture, breathability, and long-term efficacy. Emphasis is placed on reusability, biocompatibility, real-world performance, and environmental safety. Additionally, we analyze the regulatory landscape, commercialization bottlenecks, and potential directions for future-proof designs against emerging respiratory pathogens such as H5N1 and Nipah virus. While many nanoengineered systems demonstrate pronounced efficacy against enveloped viruses such as H5N1 and Nipah due to membrane-targeted oxidative and ion-mediated mechanisms, their effectiveness against structurally robust non-enveloped viruses (e.g., norovirus) remains comparatively limited and requires further investigation. This review critically evaluates the relative advantages and limitations of major nanomaterial systems, highlighting performance trade-offs between antiviral efficacy, cost, durability, and environmental impact. While nanoengineered coatings and filtration platforms show substantial promise for post-pandemic resilience, translational success will depend on standardized testing, lifecycle safety assessments, and the integration of scalable manufacturing.