Tag Archives: Nankai University

Grow inorganic functional nanomaterials—quantum dots—in the nucleus of live cells

I’m not sure that “transform[ing] cells into super cells, enabling them to do unimaginable thing,” as research Pang Dai-Wen says, is something that is necessary but he and at least one of his colleagues seem quite enthused by the prospect (you’ll find Pang’s quote in the press release which follows the news item).

An April 3, 2024 news item on phys.org announces the work, Note: Links have been removed,

National Science Review recently published research on the synthesis of quantum dots (QDs) in the nucleus of live cells by Dr. Hu Yusi, Associate Professor Wang Zhi-Gang, and Professor Pang Dai-Wen from Nankai University.

During the study of QDs synthesis in mammalian cells, it was found that the treatment with glutathione (GSH) enhanced the cell’s reducing capacity. The generated QDs were not uniformly distributed within the cell but concentrated in a specific area.

Through a series of experiments, it was confirmed that this area is indeed the cell nucleus. Dr. Hu said, “This is truly amazing, almost unbelievable.”

An April 3, 2024 Science China Press press release on EurekAlert, which originated the news item, fills in a few details,

Dr. Hu and his mentor Professor Pang attempted to elucidate the molecular mechanism of quantum dot synthesis in the cell nucleus. It was found that GSH plays a significant role. There is a GSH transport protein, Bcl-2, on the nucleus, which transports GSH into the nucleus in large quantities, enhancing the reducing ability within the nucleus, promoting the generation of Se precursors. At the same time, GSH can also expose thiol groups on proteins, creating conditions for the generation of Cd precursors. The combination of these factors ultimately enables the abundant synthesis of quantum dots in the cell nucleus.

Professor Pang stated, “This is an exciting result; this work achieves the precise synthesis of QDs in live cells at the subcellular level.” He continued, “Research in the field of synthetic biology mostly focuses on live cell synthesis of organic molecules through reverse genetics. Rarely do we see the live cell synthesis of inorganic functional materials. Our study doesn’t involve complex genetic modifications; it achieves the target synthesis of inorganic fluorescent nanomaterials in cellular organelles simply by regulating the content and distribution of GSH within the cell. This addresses the deficiency in synthetic biology for the synthesis of inorganic materials.”

While the synthesis of organic materials in cells remains predominant in the field of biosynthesis, this research undoubtedly paves the way for the synthesis of inorganic materials in synthetic biology. Professor Pang expressed, “Each of our advancements is a new starting point. We firmly believe that in the near future, we can use cell synthesis to produce nanodrugs, or even nanorobots in specified organelles. Moreover, we can transform cells into super cells, enabling them to do unimaginable things.” [emphasis mine]

Here’s a link to and a citation for the paper,

In-situ synthesis of quantum dots in the nucleus of live cells by Yusi Hu, Zhi-Gang Wang, Haohao Fu, Chuanzheng Zhou, Wensheng Cai, Xueguang Shao, Shu-Lin Liu , Dai-Wen Pang. National Science Review, Volume 11, Issue 3, March 2024, nwae021, DOI: https://doi.org/10.1093/nsr/nwae021 Published:: 12 January 2024

This paper appears to be open access.

City University of Hong Kong (CityU) and its anti-bacterial graphene face masks

This looks like interesting work and I think the integration of visual images and embedded video in the news release (on the university website) is particularly well done. I won’t be including all the graphical information here as my focus is the text.

A Sept. 10, 2020 City University of Hong Kong (CityU) press release (also on EurekAlert) announces a greener, more effective face mask,

Face masks have become an important tool in fighting against the COVID-19 pandemic. However, improper use or disposal of masks may lead to “secondary transmission”. 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 scientific 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.

Converting other materials into graphene by laser

Dr Ye has been studying the use of laser-induced graphene [emphasis mine] 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 Dr Ye’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 organisations.

Excellent anti-bacterial efficiency

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.

Dr Ye 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 fibre 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.

Dr Ye 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.

Dr Ye 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.

A new way to check the condition of the mask

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.

Laser-induced graphene (LIG), Rice University, and Dr. Ye were mentioned here in a May 9, 2018 titled: Do you want that coffee with some graphene on toast?

Back to the latest research, read the caption carefully,

Research shows that over 90% of the E. coli deposited on activated carbon fibre (fig c and d) and melt-blown fabrics (fig e and f) remained alive even after 8 hours. In contrast, most of the E. coli deposited on the graphene surface (fig a and b) were dead. (Photo source: DOI number: 10.1021/acsnano.0c05330)

Here’s a link to and a citation for the paper,

Self-Reporting and Photothermally Enhanced Rapid Bacterial Killing on a Laser-Induced Graphene Mask by Libei Huang, Siyu Xu, Zhaoyu Wang, Ke Xue, Jianjun Su, Yun Song, Sijie Chen, Chunlei Zhu, Ben Zhong Tang, and Ruquan Ye. ACS Nano 2020, 14, 9, 12045–12053 DOI: https://doi.org/10.1021/acsnano.0c05330 Publication Date:August 11, 2020 Copyright © 2020 American Chemical Society

This paper is behind a paywall.