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Cellulose (Lond) ; 29(10): 5711-5724, 2022.
Article in English | MEDLINE | ID: covidwho-1919843


The surgical masks have been essential consumables for public in the COVID-19 pandemic. However, long-time wearing masks will make wearers feel uncomfortable and massive discarded non-biodegradable masks lead to a heavy burden on our environment. In this paper, we adopt degradable chitosan@silver (CS@Ag) core-shell fibers and plant fibers to prepare an eco-friendly mask with excellent thermal comfort, self-sterilization, and antiviral effects. The thermal network of CS@Ag core-shell fibers highly improves the in-plane thermal conductivity of masks, which is 4.45 times higher than that of commercial masks. Because of the electrical conductivity of Ag, the fabricated mask can be electrically heated to warm the wearer in a cold environment and disinfect COVID-19 facilely at room temperature. Meanwhile, the in-situ reduced silver nanoparticles (AgNPs) endow the mask with superior antibacterial properties. Therefore, this mask shows a great potential to address the urgent need for a thermally comfortable, antibacterial, antiviral, and eco-friendly mask. Supplementary Information: The online version contains supplementary material available at 10.1007/s10570-022-04582-x.

Chem Eng J ; 444: 136460, 2022 Sep 15.
Article in English | MEDLINE | ID: covidwho-1797097


Most respiratory masks are made of fabrics, which only capture the infectious virus carriers into the matrix. However, these contagious viruses stay active for a long duration (∼7 days) within the fabric matrix possibly inducing post-contact transmissions. Moreover, conventional masks are vulnerable to bacterial growth with prolonged exposure to exhaled breaths. Herein, we combined violacein, a naturally-occurring antimicrobial agent, with porous nanofiber membranes to develop a series of functional filters that autonomously sterilizes viruses and bacteria. The violacein-embedded membrane inactivates viruses within 4 h (99.532 % reduction for influenza and 99.999 % for human coronavirus) and bacteria within 2 h (75.5 % reduction). Besides, its nanofiber structure physically filters out the nanoscale (<0.8 µm) and micron-scale (0.8 µm - 3 µm) particulates, providing high filtration efficiencies (99.7 % and 100 % for PM 1.0 and PM 10, respectively) with long-term stability (for 25 days). In addition, violacein provides additional UV-resistant property, which protects the skin from sunlight. The violacein-embedded membrane not only proved the sterile efficacy of microbe extracted pigments for biomedical products but also provided insights to advance the personal protective equipment (PPE) to fight against contagious pathogens.

Small ; 18(2): e2105570, 2022 01.
Article in English | MEDLINE | ID: covidwho-1540181


Airborne particulate matter (PM) pollutants, especially with nanoscale size, have caused serious public health issues. The global demand for high-performance and recyclable face masks is increasing dramatically, especially during the COVID-19 pandemic. However, present masks suffer from low-efficiency interception of PM0.3 /pathogen, limited air permeability, and incapacity to reuse and recycle. Here, multi-scale nanoarchitectured nanofiber/carbon nanotube (NF/CNT) networks are constructed by a needleless-electrospinning/spraying-netting strategy, enabling well-dispersed CNT networks (diameter ≈ 25 nm) welded on charged nanofibrous scaffolds (diameter > 100 nm) layer by layer. The optimized NF/CNT networks possess a fluffy structure with narrow-distribution small pores (size ≈ 400 nm), "free molecular flow" behavior, and electrostatic adsorption property, thereby exhibiting high filtration efficiency (>99.994% PM0.3 removal) and low resistance (<0.05% atmosphere pressure). Furthermore, they demonstrate reliable and ultra-fast photothermal-driven self-sterilization (>99.986% in 5 min) under 1 sun and electrothermal-driven self-sterilization (>99.9999% in 2 min) in sunless scenes owing to their unique nanoarchitecture. Most importantly, the abandoned NF/CNT filters can be fully recycled as high-performance solar vapor generators to desalinate seawater (3.56 L m-2 d-1 ). This work offers a fascinating solution to reduce disease transmission, resource consumption, and environmental burdens.

COVID-19 , Masks , Humans , Pandemics , SARS-CoV-2 , Sterilization
Small ; 17(42): e2102453, 2021 10.
Article in English | MEDLINE | ID: covidwho-1328617


The outbreak of COVID-19 revealed the vulnerability of commercially available face masks. Without having antibacterial/antiviral activities, the current masks act only as filtering materials of the aerosols containing microorganisms. Meanwhile, in surgical masks, the viral and bacterial filtration highly depends on the electrostatic charges of masks. These electrostatic charges disappear after 8 h, which leads to a significant decline in filtration efficiency. Therefore, to enhance the masks' protection performance, fabrication of innovative masks with more advanced functions is in urgent demand. This review summarizes the various functionalizing agents which can endow four important functions in the masks including i) boosting the antimicrobial and self-disinfectant characteristics via incorporating metal nanoparticles or photosensitizers, ii) increasing the self-cleaning by inserting superhydrophobic materials such as graphenes and alkyl silanes, iii) creating photo/electrothermal properties by forming graphene and metal thin films within the masks, and iv) incorporating triboelectric nanogenerators among the friction layers of masks to stabilize the electrostatic charges and facilitating the recharging of masks. The strategies for creating these properties toward the functionalized masks are discussed in detail. The effectiveness and limitation of each method in generating the desired properties are well-explained along with addressing the prospects for the future development of masks.

COVID-19 , Masks , Metal Nanoparticles , Pandemics/prevention & control , COVID-19/prevention & control , Filtration , Humans
ACS Appl Mater Interfaces ; 12(50): 56579-56586, 2020 Dec 16.
Article in English | MEDLINE | ID: covidwho-952789


Surgical mask is recommended by the World Health Organization for personal protection against disease transmission. However, most of the surgical masks on the market are disposable that cannot be self-sterilized for reuse. Thus, when confronting the global public health crisis, a severe shortage of mask resource is inevitable. In this paper, a novel low-cost electrothermal mask with excellent self-sterilization performance and portability is reported to overcome this shortage. First, a flexible, ventilated, and conductive cloth tape is patterned and adhered to the surface of a filter layer made of melt-blown nonwoven fabrics (MNF), which functions as interdigital electrodes. Then, a graphene layer with premier electric and thermal conductivity is coated onto the MNF. Operating under a low voltage of 3 V, the graphene-modified MNF (mod-MNF) can quickly generate large amounts of heat to achieve a high temperature above 80 °C, which can kill the majority of known viruses attached to the filter layer and the mask surface. Finally, the optimized graphene-modified masks based on the mod-MNF filter retain a relatively high particulate matter (PM) removal efficiency and a low-pressure drop. Moreover, the electrothermal masks can maintain almost the same PM removal efficiency over 10 times of electrifying, suggesting its outstanding reusability.