EAGER: Design and Processing of Anti-microbial Surfaces Using Polymer Extrusion Additive Manufacturing Embedding Silver Nanoparticles with Enhanced Ion Releasing Kinetics

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Silver nanoparticles are appealing for healthcare applications because of their strong antimicrobial ability against common bacteria and viruses. However, the concentration of nanoparticles needed to manufacture antimicrobial products can be prohibitively costly. Meanwhile, additive manufacturing has shown great potential for the rapid production of biomedical devices and personal protective equipment that desire an antimicrobial function. By incorporating silver nanoparticles into polymer filaments for material extrusion additive manufacturing, the nanoparticle quantity needed for antimicrobial parts may be substantially reduced through controlling processing settings and part geometry, while still maintaining antimicrobial characteristics. This EArly-concept Grants for Exploratory Research (EAGER) award supports fundament research that will gain knowledge on how silver nanoparticles incorporated as well as part geometric and processing conditions may influence ion releasing kinetics and the effectiveness in antimicrobial ability of fabricated parts. The research outcomes may potentially improve the ability to reduce the spread of infection diseases in medical care applications and thus benefit the well-being of the society. This project will also contribute to the education in manufacturing for students from underrepresented groups through the development of a workshop that targets students from Delgado Community College, the largest minority-serving community college in Louisiana. Students attending the workshop will gain exposures to the materials of this project and additional education and research opportunities in advanced manufacturing areas.The objective of this research is to understand how additive manufacturing processing and designs govern the concentration of silver nanoparticles on fabricated surfaces that require antimicrobial properties. The adhesion and growth of bacteria and the release of silver ions that eradicate bacteria depend not only on surface topography but also the internal voids of a part. The novelty of the approach lies upon employing deposition infill patterns, layer heights, and nozzle sizes to produce specimens with (i) surface topography with high tortuosity that limits favorable attachment sites and confines the growth of surface bacteria, and (ii) increased internal voids, while without sacrificing other component performance, for a higher release rate of antimicrobial silver ions at part surfaces. The interdisciplinary research team will test these outcomes by characterization of specimen morphologies, silver ion release rates, and the adhesion and growth of the common bacteria Escherichia coli and Staphylococcus aureus by optical and electron microscopy, mass spectrometry, and antimicrobial assays, respectively. The project will offer a better understanding of how additive manufacturing processing and design parameters influence the antimicrobial mechanisms, which can be used to develop design strategies for a wide range of cost-effective healthcare applications that can be used to limit infection rates.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.