Low-cost, reusable photo-thermal materials could reduce medical waste

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A production method for a novel fabric that integrates with existing mass production methods, promises an economical way to make reusable medical masks and other protective gear that can be sterilized using light.

The graphene-containing meltblown fabric, developed by researchers at Wuhan University of Technology in China could help dramatically reduce medical waste while offering the same level of protection provided by disposable masks.

To develop next-generation medical protective equipment, the goal of this work is to make materials that are highly effective and recyclable, explains Yi Lu, a material researcher who led the research behind the fabric.

Disposable medical personal protective equipment (PPE) represents significant levels of waste globally, which reached epic proportions during the COVID-19 pandemic. Despite the development of various technologies for reusable PPE such as masks, no approach has yet been able to simultaneously achieve high protection, effective sterilizability, low cost and simple scalability.

To overcome these problems, researchers from the Wuhan University of Technology developed a technique for manufacturing a graphene-meltblown fabric. Meltblowing is a technique that creates ultrafine fibres that can capture microorganisms. Spray-pressing was used to add nanoparticulate carbon, or graphene, to the material to enable sterilisation.

A new approach

Medical face masks, one kind of frequently used medical PPE, are designed to filter contagious microbial particles from the air.

The international ‘N95’ standard requires that a mask filters out 95% of airborne particles that are 0.3 micrometres in size. This is generally achieved by a filtration layer that is made of meltblown fabric.

Once used, bacterial and viral particles accumulate in the layer, making the masks a potential source of infection that requires careful disposal.

To make masks reusable, they must be sterilizable in a reliably and non-destructive manner. This can be achieved by coating a filtration layer with nanoparticulate graphene, which provides a ‘photo-thermal’ sterilization effect by generating intense heat on the nanoparticles’ surfaces when exposed to light.

However, existing methods for incorporating graphene sheets into masks rely on expensive, laser-based deposition processes that can’t be easily incorporated into standard mass-production protocols.

A materials scientist at Wuhan University of Technology in China, is testing the photothermal performance of reusable mask. Credit: Wuhan University of Technology

The spray-pressing method developed by this team simply requires the addition of a spray unit to a traditional mask manufacturing machine.

The graphene-meltblown fabric not only shows better filtration performance than N95 standards, but also has excellent water vapour adsorption and desorption capabilities, which are important for comfort and wearability.

Reducing graphene cost

Another key challenge faced by the team was the high cost of the graphene used to fabricate the photothermal sterilization layer.

To address this issue, they developed a low-cost graphene production process that uses a simple technique to make large amounts of graphene from bitumen. A graphene production plant capable of producing up to one tonne of graphene annually via this method has now been constructed.

Benefit from the new technologies, masks that can be sterilized and reused up to 50 times will become available, each use lasting up to 12 hours. The cost of 100 reusable masks is only US$0.15 more than disposable medical masks. 1

The researchers believe that the healthcare industry and the research community need to work on better solutions to deal with future disease outbreaks.

“We hope that sharing this technology will increase the diversity of voices that contribute to developing ethical guidelines concerning the use of medical protective gear,” comments the researcher, “The new technology will speed up the development of advanced PPE, and effectively address the shortage of medical supplies in underdeveloped regions.”

Contact details:

Wuhan University of Technology

english.whut.edu.cn

Email: [email protected], Yi Lu; [email protected], Xiao-Yu Yang

Lu, Y., et al. iScience 26, 107286 (2023).

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