Reusable Cu2-xS-modified masks with infrared lamp-driven antibacterial and antiviral activity for real-time personal protection

Abstract

Disposable surgical masks are widely used by the general public since the onset of the coronavirus outbreak in 2019. However, current surgical masks cannot self-sterilize for reuse or recycling for other purposes, resulting in high economic and environmental costs. To solve these issue, herein we report a novel low-cost surgical mask decorated with copper sulfide (Cu_2-xS) nanocrystals for photothermal sterilization in a short time (6 min). With the spun-bonded nonwoven fabrics (SNF) layer from surgical masks as the substrate, Cu_2-xS nanocrystals are in-situ grown on their surface with the help of a commercial textile adhesion promoter. The SNF-Cu_2-xS layer possesses good hydrophobicity and strong near infrared absorption. Under the irradiation with an infrared baking lamp (IR lamp, 50 mW cm^-2), the surface temperature of SNF-Cu_2-xS layer on masks can quickly increase to over 78 °C, resulting from the high photothermal effects of Cu_2-xS nanocrystals. As a result, the polluted masks exhibit an outstanding antibacterial rate of 99.9999% and 85.4% for the Escherichia coli (E.coli) and Staphylococcus aureus (S. aureus) as well as the inactivation of human coronavirus OC43 (3.18-log₁₀ decay) and influenza A virus A/PR/8/34 (H1N1) (3.93-log₁₀ decay) after 6 min irradiation, and achieve rapid sterilization for reuse and recycling. Therefore, such Cu_2-xS-modified masks with IR lamp-driven antibacterial and antiviral activity have great potential for real-time personal protection.

Keywords: Antibacterial; Antiviral; Facemasks; Infrared baking lamp; Photothermal effect.

Graphical abstract

Fig. 1

a) A scheme showing the surgical facemasks with surface aerosols/droplets containing bacteria and viruses. The SNF-Cu_2-xS with bactericidal and antiviral capacity under IR lamp. b) Illustration of the antibacterial and antiviral mechanism of SNF-Cu_2-xS through hyperthermia and Cu⁺ ions.

Fig. 2

a) Schematic illustration of the preparation process of SNF-Cu_2-xS. b-d) SEM images of SNF. e-g) SEM images of SNF-Cu_2-xS.

Fig. 3

a) EDS elemental mapping of SNF-Cu_2-xS. b) TEM and HRTEM images of Cu_2-xS nanocrystals obtained from the SNF-Cu_2-xS. c) XRD pattern of Cu_2-xS nanocrystals. d) Cu 2p spectrum.

Fig. 4

Photographs of a water droplet on the surface of a) the pristine SNF and b) SNF-Cu_2-xS at 0 and 3 s. c) Absorption spectra of SNF and SNF-Cu_2-xS.

Fig. 5

Thermographic images of a) SNF and c) SNF-Cu_2-xS. The corresponding temperature elevation curves of b) SNF and d) SNF-Cu_2-xS under different power densities.

Fig. 6

a) Schematic diagram of photothermal sterilization. b) Photographs of the E. coli colonies on LB agar solid plates after the treatments with SNF-Cu_2-xS and IR lamp (50 mW cm⁻², 0–6 min). c) SEM images of E. coli. d) The survival rate of E. coli treated with SNF or SNF-Cu_2-xS at 50 mW cm⁻² for different durations (***p < 0.001 (highly significant)). e) The survival rate of E. coli treated with SNF or SNF-Cu_2-xS at 50–200 mW cm⁻² for 2 min (***p < 0.001). f) The repeated antibacterial rate of SNF-Cu_2-xS.

Fig. 7

Inactivation kinetics of a) HCoV-OC43 and b) PR8 by SNF or SNF-Cu_2-xS upon IR lamp at 50 mW cm⁻² for 2–6 min (***p < 0.001). c) TEM images of HCoV-OC43. d) TEM images of inactivated HCoV-OC43 after the treatment with SNF-Cu_2-xS and IR lamp at 50 mW cm⁻² for 2 min. e) A schematic diagram of morphology transformation of HCoV-OC43.

Fig. 8

a) Schematic illustration of Cu_2-xS-modified mask illuminated by IR lamp. b) The temperature elevation curves of SNF-Cu_2-xS layer and SNF layer under IR lamp stimulation.