Ye Ruquan,'s team uses the CO2 infrared laser system to generate graphene. Experiment results show that the graphene they produced exhibit a much better anti-bacterial efficiency than activated carbon fiber and melt-blown fabrics. Courtesy of City University of Hong Kong
A research team from City University of Hong Kong (CityU) has successfully produced graphene masks with an anti-bacterial efficiency of 80%, which can be enhanced to almost 100% with exposure to sunlight for around 10 minutes. Initial tests also showed very promising results in the deactivation of two species of coronaviruses. The graphene masks are easily produced at low cost, and can help to resolve the problems of sourcing raw materials and disposing of non-biodegradable masks.
The research is conducted by Dr. Ye Ruquan, assistant professor from CityU's Department of Chemistry, in collaboration with other researchers. The findings were published in the journal ACS Nano, titled "Self-Reporting and Photothermally Enhanced Rapid Bacterial Killing on a Laser-Induced Graphene Mask."
Commonly used surgical masks are not anti-bacterial. This may lead to the risk of secondary transmission of bacterial infection when people touch the contaminated surfaces of the used masks or discard them improperly. Moreover, the melt-blown fabrics used as a bacterial filter poses an impact on the environment as they are difficult to decompose. Therefore, scientists have been looking for alternative materials to make masks.
Ruquan has been studying the use of laser-induced graphene in developing sustainable energy. When he was studying PhD degree at Rice University several years ago, the research team he participated in and led by his supervisor discovered an easy way to produce graphene. They found that direct writing on carbon-containing polyimide films (a polymeric plastic material with high thermal stability) using a commercial CO2 infrared laser system can generate 3D porous graphene. The laser changes the structure of the raw material and hence generates graphene. That's why it is named laser-induced graphene.
Graphene is known for its anti-bacterial properties, so as early as last September, before the outbreak of COVID-19, producing outperforming masks with laser-induced graphene already came across Ruquan's mind. He then kick-started the study in collaboration with researchers from the Hong Kong University of Science and Technology (HKUST), Nankai University, and other organizations.
The research team tested their laser-induced graphene with E. coli, and it achieved high anti-bacterial efficiency of about 82%. In comparison, the anti-bacterial efficiency of activated carbon fibre and melt-blown fabrics, both commonly-used materials in masks, were only 2% and 9% respectively. Experiment results also showed that over 90% of the E. coli deposited on them remained alive even after 8 hours, while most of the E. coli deposited on the graphene surface were dead after 8 hours. Moreover, the laser-induced graphene showed a superior anti-bacterial capacity for aerosolised bacteria.
Ruquan said that more research on the exact mechanism of graphene's bacteria-killing property is needed. But he believed it might be related to the damage of bacterial cell membranes by graphene's sharp edge. And the bacteria may be killed by dehydration induced by the hydrophobic (water-repelling) property of graphene.
Previous studies suggested that COVID-19 would lose its infectivity at high temperatures. So the team carried out experiments to test if the graphene's photothermal effect (producing heat after absorbing light) can enhance the anti-bacterial effect. The results showed that the anti-bacterial efficiency of the graphene material could be improved to 99.998% within 10 minutes under sunlight, while activated carbon fiber and melt-blown fabrics only showed an efficiency of 67% and 85% respectively.
The team is currently working with laboratories in mainland China to test the graphene material with two species of human coronaviruses. Initial tests showed that it inactivated over 90% of the virus in five minutes and almost 100% in 10 minutes under sunlight. The team plans to conduct testings with the COVID-19 virus later.
Their next step is to further enhance the anti-virus efficiency and develop a reusable strategy for the mask. They hope to release it to the market shortly after designing an optimal structure for the mask and obtaining the certifications.
Ruquan described the production of laser-induced graphene as a "green technique". All carbon-containing materials, such as cellulose or paper, can be converted into graphene using this technique. And the conversion can be carried out under ambient conditions without using chemicals other than the raw materials, nor causing pollution. And the energy consumption is low.
"Laser-induced graphene masks are reusable. If biomaterials are used for producing graphene, it can help to resolve the problem of sourcing raw material for masks. And it can lessen the environmental impact caused by the non-biodegradable disposable masks," he added.
Ruquan pointed out that producing laser-induced graphene is easy. Within just one and a half minutes, an area of 100 cm² can be converted into graphene as the outer or inner layer of the mask. Depending on the raw materials for producing the graphene, the price of the laser-induced graphene mask is expected to be between that of surgical mask and N95 mask. He added that by adjusting laser power, the size of the pores of the graphene material can be modified so that the breathability would be similar to surgical masks.
To facilitate users to check whether graphene masks are still in good condition after being used for a period of time, the team fabricated a hygroelectric generator. It is powered by electricity generated from the moisture in human breath. By measuring the change in the moisture-induced voltage when the user breathes through a graphene mask, it provides an indicator of the condition of the mask. Experiment results showed that the more the bacteria and atmospheric particles accumulated on the surface of the mask, the lower the voltage resulted. "The standard of how frequently a mask should be changed is better to be decided by the professionals. Yet, this method we used may serve as a reference," suggested Dr Ye.
The study was supported by CityU and Nankai University.
I really love this post I will visit again to read your post in a very short time and I hope you will make more posts like this.
Really enjoyed this blog post.Really thank you! Cool.
I really enjoy the blog post.Really looking forward to read more.
Fantastic article post. Really Cool.
Thank you for the auspicious writeup. It in reality used to be a amusement account it.Glance advanced to more delivered agreeable from you! By the way,how could we be in contact?
Sad story but that’s how it is. bit weird and we obviously acheter clenbuterol
Thanks-a-mundo for the post.Really thank you! Really Great.
wow, awesome article post.Thanks Again. Really Great.
Thanks for sharing, this is a fantastic article.Really thank you! Great.
Hey, thanks for the post. Want more.
Thanks for the blog article.Much thanks again. Cool.
I appreciate you sharing this blog article.Thanks Again. Fantastic.
I value the blog.Really thank you! Awesome.
Im thankful for the post.Thanks Again. Awesome.
I enjoy what you guys are usually up too. This kind of clever work and exposure! Keep up the superb works guys I’ve incorporated you guys to blogroll.
I really enjoy the post.Really looking forward to read more. Much obliged.
A round of applause for your blog.Really thank you!
Thanks-a-mundo for the post.Really thank you!
I am so grateful for your blog article.Much thanks again. Will read on…
Thanks , I’ve just been searching for info about thistopic for a long time and yours is the greatest I’ve came upon so far.But, what in regards to the conclusion? Are you positive concerning the supply?
ivermectin dosage dog ivermectin tractor supply
Looking forward to reading more. Great blog.Really thank you! Great.
I used to be suggested this blog by means of my cousin. I’m no longer positive whether or not this publish is written by way of him as nobody else understand such targeted about my problem. You are wonderful! Thank you!
I¡¦m now not certain the place you’re getting your info, however good topic. I must spend a while studying more or understanding more. Thank you for magnificent info I was on the lookout for this information for my mission.
F*ckin remarkable issues here. I am very glad to peer your post. Thank you a lot and i’m taking a look forward to touch you. Will you please drop me a e-mail?
Muchos Gracias for your article.Really looking forward to read more. Cool.
generic provigil online
I want to to thank you for this good read!! I certainly loved every bit of it. I’ve got you bookmarked to check out new stuff you postÖ
Thanks for sharing such a pleasant thinking, articleis pleasant, thats why i have read it entirely
Hi, I do believe this is a great blog. I stumbledupon it 😉 I am going to revisit once again since i have book-marked it. Money and freedom is the best way to change, may you be rich and continue to guide others.
Heya! I’m at work surfing around your blog from my new iphone4! Just wanted to say I love reading your blog and look forward to all your posts!Keep up the great work!
Hello, after reading this amazing article i aam as well happy to sharemy familiarity here with mates!
Hey there! This is my first visit to your blog! We are a team of volunteers and starting a new initiative in a community in the same niche. Your blog provided us useful information to work on. You have done a marvellous job!
A round of applause for your blog post.Much thanks again. Fantastic.
Fastidious answer back in return of this question with firm arguments and telling everything on the topic of that.
I will immediately clutch your rss feed as I can not to find youremail subscription hyperlink or newsletter service.Do you’ve any? Kindly allow me recognize so that I may subscribe.Thanks.
Thanks so much for the article post.Much thanks again.
I value the blog article.Really thank you! Really Cool.
I am so grateful for your blog post.Much thanks again. Much obliged.
Very good blog article. Great.
Thank you for your blog. Great.
Nlefjx – new propecy quest game online Ehzjeh xmjmqj
Good day! I know this is kind of off topic but I was wondering if you knew where I could get a captcha plugin for my comment form?I’m using the same blog platform as yours and I’m having problems finding one?Thanks a lot!
I think this is a real great blog.Much thanks again. Keep writing.
Heya i am for the first time here. I came across thisboard and I find It really useful & it helped me out a lot.I hope to give something back and aid others like you helped me.
Thank you ever so for you blog post.Really thank you! Want more.
apartments in aiken sc apartment therapy amsterdam apartments