A new material for airborne virus filtration

Only facepiece respirators of FFP2 or FFP3 type by European standards (N95 by US standards) can provide effective protection against airborne viruses. However, these respirators are expensive and many third-world countries would be unable to afford them if a severe pandemic starts. The present study reports a chemical modification of the surface of low-cost non-woven cellulosic fiber filters by fixing poly(ethylenimine) (PEI) in order to give them an antiviral property. The virus filtration experiments were performed by spraying an aerial suspension of T4D bacteriophage virus of Escherichia coli B through the filter. The coating of the non-woven fiber by the antiviral entity was optimized. The best virus capture factor f (ratio of mother-solution virus content to downstream virus content) was obtained with 2 layers of Kimwipes® functionalized with a PEI solution (4.4% w/v) (f = 3 × 105). When these 2 layers were placed inside a commercial medical mask in place of its cellulosic layer (Kolmi M24001 mask) (f = 3.5 × 104), the f ratio reached 1.8 × 10, 7for 1 h of filtration. This novel medical mask with additional antiviral properties represents a significant improvement over conventional medical masks. The system was also tested with respect to the respiratory low pathogenic A (H5N2) influenza virus. No virus was detected on the downstream side of the filters during the filtration. Moreover, the system captured alive the virus making possible applications to pre-concentration of airborne viruses for medical tests or research experiments.

► In this study we modify the surface of low-cost filters by fixing poly(ethylenimine) (PEI) to give them an antiviral property. ► Two layers of Kimwipes® functionalized with PEI give the best virus retention. ► Two layers of Kimwipes® functionalized with PEI placed inside a commercial medical mask strongly improve the virus retention. ► The new medical mask with additional antiviral properties represents a significant improvement over conventional medical masks