During the current coronavirus pandemic, there is a shortage of masks that are part of personal protective equipment used by health care workers. This shortage is due to two reasons: (i) supply has been outstripped by unprecedented demand, and (ii) current masks are meant to be used only once and then discarded. Critically, the lack of proper and effective personal protective equipment poses a significant risk to healthcare workers that are treating and caring for COVID19 patients. This RAPID project seeks to remedy these issues by fabricating novel and improved filters using polymers derived from natural sources (agriculture and forestry) that are compostable. These filters would be removable, renewable, and reusable. Furthermore, these filters would incorporate small-sized antimicrobial/antiviral copper particles, which enhance the effectiveness of masks beyond current capabilities. This project will rapidly develop and optimize the fabrication of these filters. Developed filters will be tested to demonstrate that they have all the properties required for masks to be worn by medical personnel. If the research is successful, it will result in the development of a reusable medical mask that is superior to the single-use mask currently in use. Finally, the project will promote collaborations across different fields such as wood science, health science, engineering, chemistry and biology which, in turn, will support training and education of students in these fields.<br/><br/>The overarching objective of this RAPID research project is to develop a prototype for a reusable and environmentally friendly biofilter with antimicrobial and antiviral properties to be used as a filtering facepiece respirator. This objective will be attained with the use of bio-nanocomposites of polylactic acid in combination with cellulose nanofibrils and coated with copper nanoparticles. The result will represent improvements on current medical masks, including the design, fabrication processing and material properties. Process development will involve mixing cellulose nanofibrils into polylactic acid and converting the compounded material into filaments coated with copper nanoparticles, rendering the material suitable for additive manufacturing of the reusable biofilter. The copper nanoparticles will endow the filter with antimicrobial and antiviral properties, while the properly-dispersed nanocellulose will help to retain the microorganisms and also provide mechanical integrity. It is expected that masks using these filters will have the ability to both prevent penetration by microorganisms (having a diameter as small as 50 nm) and to kill many infectious agents as well. Rejuvenation of the filter will be done with the help of mild heat treatment. The structure and properties of the filters will be determined using standardized tests. The ability to compost polylactic acid will be helpful in the eventual disposal of the filter. If successful, the research will result in the development of a reusable respirator mask that is superior to the present-day mask. This will help to ease the shortage of personal protective equipment for health care workers and give them the best possible protection against microbial threats such as COVID19. Finally, the successful completion of the project will advance the knowledge and understanding of bio-nanocomposite components compatibility, and their specific effects on the final material performance within the context of engineering and technology education. This new knowledge will be generated across different fields such as wood science, health science, engineering, chemistry and biology. The proposed work will support synergies among these disciplines and foster training and education of students in these fields.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.