Bacterial Biofilm Formation on Nano-Copper Added PLA Suited for 3D Printed Face Masks

Abstract

The COVID-19 Pandemic leads to an increased worldwide demand for personal protection equipment in the medical field, such as face masks. New approaches to satisfy this demand have been developed, and one example is the use of 3D printing face masks. The reusable 3D printed mask may also have a positive effect on the environment due to decreased littering. However, the microbial load on the 3D printed objects is often disregarded. Here we analyze the biofilm formation of Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli on suspected antimicrobial Plactive™ PLA 3D printing filaments and non-antimicrobial Giantarm™ PLA. To characterize the biofilm-forming potential scanning electron microscopy (SEM), Confocal scanning electron microscopy (CLSM) and colony-forming unit assays (CFU) were performed. Attached cells could be observed on all tested 3D printing materials. Gram-negative strains P. aeruginosa and E. coli reveal a strong uniform growth independent of the tested 3D filament (for P. aeruginosa even with stressed induced growth reaction by Plactive™). Only Gram-positive S. aureus shows strong growth reduction on Plactive™. These results suggest that the postulated antimicrobial Plactive™ PLA does not affect Gram-negative bacteria species. These results indicate that reusable masks, while better for our environment, may pose another health risk.

Magnetron Sputtering of Transition Metals as an Alternative Production Means for Antibacterial Surfaces

“…New technologies are necessary combat bacteria, often multi resistant to antibiotics, in our environment. In a recent study, we analyzed the potential antimicrobial property of copper nanoparticle-infused polylactic acid [29]. Interestingly, we could not show any growth inhibition with the bacterium used in both studies, a wild-type Pseudomonas aeruginosa, isolated from washing machines.…”

Recent advances and future perspectives in engineering biodegradable face masks

“…In recent years, the 3D printing of PLA has attracted attention as an affordable and attainable method of manufacturing face masks. [124][125][126] PLA is available in a wide range of colours to customise the masks. For instance, He and co-workers fabricated transparent, biodegradable PLA air lters by electrospinning PLA bers on aluminium foil, followed by PLA 3D printing over the electrospun layer.…”

Nanogallium-poly(L-lactide) Composites with Contact Antibacterial Action

“…During the pandemic, three billion masks were discarded worldwide, putting enormous pressure on the environment [ 11 , 12 ]. A single mask can release 1.5 million microplastic particles [ 13 , 14 , 15 ]. Substituting the scarcely degradable plastics in the masks with PLA could solve this issue [ 16 ].…”

“…Since PLA is sensitive to all available sterilizing methods [ 26 ] and can become easily contaminated after sterilization, antibacterial components are frequently added to it. The range of antibacterial agents introduced so far has been vast: antibiotics [ 27 ], antibacterial peptides [ 28 , 29 ], chitosan [ 23 , 30 , 31 ], essential oils, volatile plant extracts, and other natural antimicrobials [ 23 , 32 , 33 , 34 , 35 ], but also various inorganic nanomaterials—in particular, silver [ 36 , 37 , 38 , 39 , 40 , 41 ], copper [ 13 , 39 ], and metal oxides (TiO 2 [ 39 ], ZnO [ 42 , 43 , 44 ], MgO [ 45 , 46 ], CaO [ 47 ]).…”