Needleless electrospun phytochemicals encapsulated nanofibre based 3-ply biodegradable mask for combating COVID-19 pandemic

Abstract

The emergence of COVID-19 pandemic has severely affected human health and world economies. According to WHO guidelines, continuous use of face mask is mandatory for personal protection for restricting the spread of bacteria and virus. Here, we report a 3-ply cotton-PLA-cotton layered biodegradable face-mask containing encapsulated phytochemicals in the inner-filtration layer. The nano-fibrous PLA filtration layer was fabricated using needleless electrospinning of PLA & phytochemical-based herbal-extracts. This 3-layred face mask exhibits enhanced air permeability with a differential pressure of 35.78 Pa/cm² and superior bacterial filtration efficiency of 97.9% compared to conventional face masks. Close-packed mesh structure of the nano-fibrous mat results in effective adsorption of particulate matter, aerosol particles, and bacterial targets deep inside the filtration layer. The outer hydrophobic layer of mask exhibited effective blood splash resistance up to a distance of 30 cm, ensuring its utilization for medical practices. Computational analysis of constituent phytochemicals using the LibDock algorithm predicted inhibitory activity of chemicals against the protein structured bacterial sites. The computational analysis projected superior performance of phytochemicals considering the presence of stearic acid, oleic acid, linoleic acid, and Arachidic acid exhibiting structural complementarity to inhibit targeted bacterial interface. Natural cotton fibers and PLA bio-polymer demonstrated promising biodegradable characteristics in the presence of in-house cow-dung based biodegradation slurry. Addition of jaggery to the slurry elevated the biodegradation performance, resulting in increment of change of weight from 07% to 12%. The improved performance was attributed to the increased sucrose content in biodegradation slurry, elevating the bacterial growth in the slurry. An innovative face mask has shown promising results for utilization in day-to-day life and medical frontline workers, considering the post-pandemic environmental impacts.

Keywords: Bacterial Filtration; Biodegradable; Electrospinning; Face mask; LibDock Algorithm; Phytochemicals.

Graphical abstract

Fig. 1

Assembly for needleless electrospinning of polymer solution.

Fig. 2

Working principle for testing of air permeability by using standard IS 16289:2014.

Fig. 3

FE-SEM micrographs of PLA nano-fibrous layer at (A) magnification of 1 µm, and accelerating voltage of 5 kV, (B) magnification of 3 µm, and accelerating voltage of 5 kV.

Fig. 4

AFM micrographs of developed PLA nanofibers revealing (a) 2D, and (b) 3D surface morphology.

Fig. 5

(a) Contact angle measurements of the C6 fluorocarbon coated surface, cotton fabric surface, and PLA/Neem electrospun layer, (b) Cassie-Baxter state of the surface and superhydrophilic nature of the cotton fabric.

Fig. 6

Pictorial representation of water molecules' interaction with the top layer, middle layer, and the inner layers of the face mask.

Fig. 7

Computational heat map analysis of herbal phytochemicals' chemical constituents containing Azadirachta Indica and Eucalyptus Citriodora against protein structures of the bacteria. (2YA4- Neuraminidase (NA) protein from Streptococcus pneumonia, 5CPH- DNA gyrase subunit B from Staphylococcus aureus, 5O77 - OmpK35 from Klebsiella pneumonia, 4FYE- SidF form Legionella pneumophila, 3ZH7 - Protein E from Haemophilus Influenzae).

Fig. 8

FE-SEM images of the biodegraded samples at accelerating voltage of 2.5 kV, (A) PLA surface after 30 days treatment in cow-dung and water containing biodegradation slurry, (B) PLA surface after 20 days treatment in cow-dung, jaggery and water containing biodegradation slurry, (C) Cotton surface after 30 days treatment in cow-dung and water containing biodegradation slurry, and (D) Cotton surface after 20 days treatment in cow-dung, jaggery and water containing biodegradation slurry.