Cellulose, nanocellulose, and antimicrobial materials for the manufacture of disposable face masks: A review

Abstract

Cellulose is among the most promising renewable and biodegradable materials that can help meet the challenge of replacing synthetic fibers currently used in disposable N95 respirators and medical face masks. Cellulose also offers key functionalities that can be valued in filtration applications using approaches such as nanofiltration, membrane technologies, and composite structures, either through the use of nanocellulose or the design of functional composite filters. This paper presents a review of the structures and compositions of N95 respirators and medical face masks, their properties, and regulatory standards. It also reviews the use of cellulose and nanocellulose materials for mask manufacturing, along with other (nano)materials and composites that can add antimicrobial functionality to the material. A discussion of the most recent technologies providing antimicrobial properties to protective masks (by the introduction of natural bioactive compounds, metal-containing materials, metal-organic frameworks, inorganic salts, synthetic polymers, and carbon-based 2D nanomaterials) is presented. This review demonstrates that cellulose can be a solution for producing biodegradable masks from local resources in response to the high demand due to the COVID-19 pandemic and for producing antimicrobial filters to provide greater protection to the wearer and the environment, reducing cross-contamination risks during use and handling, and environmental concerns regarding disposal after use.

A Critical Review of the Antimicrobial and Antibiofilm Activities of Green-Synthesized Plant-Based Metallic Nanoparticles

“…Cellulose is a ubiquitous natural polymer which can be produced from a broad range of biomass. It is the key component in natural fibers and an excellent candidate for synthesis of bio-based materials due to its various physicochemical properties, including biodegradability, biocompatibility, environmental friendliness, renewability, affordability and colloidal stability [ 114 , 115 ].…”

“…It is essentially produced through chemical or mechanical action on the plant cellulose or bacterial cellulose. Nanocellulose is classified into cellulose nanocrystals, cellulose nanofibers and bacterial nanocellulose [ 108 , 114 , 115 ]. Apart from plant materials (e.g., wood, oil palm biomass, bamboo, rice husk, coconut husk), cellulose nanocrystals and cellulose nanofibrils can also be extracted from tunicate, a type of marine invertebrate.…”

“…However, by functionalization with green metal/metal oxide nanoparticles (e.g., Au, Ag, Cu, CuO, MgO, ZnO, Fe 3 O 4 and TiO 2 ), it is possible to endow nanocellulose composites with antimicrobial properties ( Figure 4 ) [ 118 , 119 ]. These biosynthesized metal-based antimicrobial agents may also exhibit good efficacy and resilience towards microbial resistance [ 114 , 117 ]. In this context, Mocanu et al [ 120 ] recently demonstrated the impact of functionalization of bacterial nanocellulose with ZnO NPs, green-synthesized using propolis extract, on antimicrobial activity against Bacillus subtilis and Candida albicans , in comparison to ZnO NPs and the extract alone.…”

Face Masks to Combat Coronavirus (COVID-19)—Processing, Roles, Requirements, Efficacy, Risk and Sustainability

“…The melt-blown intermediate hydrophobic porous structure is made of PP fibers; however, polyester derivatives are sometimes employed instead. The thermoplastic fiber diameter ranges between 0.1 and 10 microns to achieve high filtration efficiency, high strength, lightness, and good breathability [ 44 ]. High-porosity spun-bond fabrics have a thickness of 100 to 1000 microns and a larger fiber diameter (15–40 microns) than melt-blown fabrics [ 45 , 76 ].…”

“…In Europe, European Standards Organization (EN) certifies surgical masks. Medical face masks must meet a few specifications for filtering according to the ASTM F2100-19e1 [ 44 ], including bacterial filtration efficiency (BFE), submicron particulate filtration efficiency (PFE), differential pressure (ΔP, an indicator of the breathability of the mask), flammability, etc. Both BFE and PFE must meet the requirements of ≥95% for low-barrier face masks (level 1) and ≥98% for moderate- and high-barrier face masks (levels 2 and 3).…”