Tag Archives: Rensselaer Polytechnic Institute (RPI)

Transforming electronics with metal-breathing bacteria

‘Metal-breathing’ bacteria, eh? A July 28, 2020 news item on Nanowerk announces the research into new materials for electronics (Note: A link has been removed),

When the Shewanella oneidensis bacterium “breathes” in certain metal and sulfur compounds anaerobically, the way an aerobic organism would process oxygen, it produces materials that could be used to enhance electronics, electrochemical energy storage, and drug-delivery devices.

The ability of this bacterium to produce molybdenum disulfide – a material that is able to transfer electrons easily, like graphene – is the focus of research published in Biointerphases (“Synthesis and characterization of molybdenum disulfide nanoparticles in Shewanella oneidensis MR-1 biofilms”) by a team of engineers from Rensselaer Polytechnic Institute.

A July 28, 2020 Rensselaer Polytechnic Institute (RPI) news release (also on EurekAlert) by Torie Wells, which originated the news item, describes the work in more detail,

“This has some serious potential if we can understand this process and control aspects of how the bacteria are making these and other materials,” said Shayla Sawyer, an associate professor of electrical, computer, and systems engineering at Rensselaer.

The research was led by James Rees, who is currently a postdoctoral research associate under the Sawyer group in close partnership and with the support of the Jefferson Project at Lake George — a collaboration between Rensselaer, IBM Research, and The FUND for Lake George that is pioneering a new model for environmental monitoring and prediction. This research is an important step toward developing a new generation of nutrient sensors that can be deployed on lakes and other water bodies.

“We find bacteria that are adapted to specific geochemical or biochemical environments can create, in some cases, very interesting and novel materials,” Rees said. “We are trying to bring that into the electrical engineering world.”

Rees conducted this pioneering work as a graduate student, co-advised by Sawyer and Yuri Gorby, the third author on this paper. Compared with other anaerobic bacteria, one thing that makes Shewanella oneidensis particularly unusual and interesting is that it produces nanowires capable of transferring electrons [emphasis mine].

“That lends itself to connecting to electronic devices that have already been made,” Sawyer said. “So, it’s the interface between the living world and the manmade world that is fascinating.”

Sawyer and Rees also found that, because their electronic signatures can be mapped and monitored, bacterial biofilms could also act as an effective nutrient sensor that could provide Jefferson Project researchers with key information about the health of an aquatic ecosystem like Lake George.

“This groundbreaking work using bacterial biofilms represents the potential for an exciting new generation of ‘living sensors,’ which would completely transform our ability to detect excess nutrients in water bodies in real-time. This is critical to understanding and mitigating harmful algal blooms and other important water quality issues around the world,” said Rick Relyea, director of the Jefferson Project.

Sawyer and Rees plan to continue exploring how to optimally develop this bacterium to harness its wide-ranging potential applications.

“We sometimes get the question with the research: Why bacteria? Or, why bring microbiology into materials science?” Rees said. “Biology has had such a long run of inventing materials through trial and error. The composites and novel structures invented by human scientists are almost a drop in the bucket compared to what biology has been able to do.”

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

Synthesis and characterization of molybdenum disulfide nanoparticles in Shewanella oneidensis MR-1 biofilms by James D. Rees, Yuri A. Gorby, and Shayla M. Sawyer. Biointerphases 15, 041006 (2020) DOI: https://doi.org/10.1116/6.0000199 Published Online: 24 July 2020

This paper is behind a paywall.

Living skin with blood vessels can be 3D printed

This is a big step forward but it’s not for the faint at heart. Scientists have successfully 3D printed human skin with blood vessels and grafted them onto mice. Rensselaer Polytechnic Institute and Yale University researchers worked together on this tissue engineering project. This video features Renseellaer’s Pankaj Kraande discussing the research,

Here’s a November 1, 2019 Rensselaer Polytechnic news release (also received via email and it’s on EurekAlert) describing the work in detail,

Researchers at Rensselaer Polytechnic Institute have developed a way to 3D print living skin, complete with blood vessels. The advancement, published online today [Nov. 1, 2019] in Tissue Engineering Part A, [the paper is behind a pywall] is a significant step toward creating grafts that are more like the skin our bodies produce naturally.

“Right now, whatever is available as a clinical product is more like a fancy Band-Aid,” said Pankaj Karande, an associate professor of chemical and biological engineering and member of the Center for Biotechnology and Interdisciplinary Studies (CBIS), who led this research at Rensselaer. “It provides some accelerated wound healing, but eventually it just falls off; it never really integrates with the host cells.”

A significant barrier to that integration has been the absence of a functioning vascular system in the skin grafts.

Karande has been working on this challenge for several years, previously publishing one of the first papers showing that researchers could take two types of living human cells, make them into “bio-inks,” and print them into a skin-like structure. Since then, he and his team have been working with researchers from Yale School of Medicine to incorporate vasculature.

In this paper, the researchers show that if they add key elements — including human endothelial cells, which line the inside of blood vessels, and human pericyte cells, which wrap around the endothelial cells — with animal collagen and other structural cells typically found in a skin graft, the cells start communicating and forming a biologically relevant vascular structure within the span of a few weeks. …

“As engineers working to recreate biology, we’ve always appreciated and been aware of the fact that biology is far more complex than the simple systems we make in the lab,” Karande said. “We were pleasantly surprised to find that, once we start approaching that complexity, biology takes over and starts getting closer and closer to what exists in nature.”

Once the Yale team grafted it onto a special type of mouse, the vessels from the skin printed by the Rensselaer team began to communicate and connect with the mouse’s own vessels.

“That’s extremely important, because we know there is actually a transfer of blood and nutrients to the graft which is keeping the graft alive,” Karande said.

In order to make this usable at a clinical level, researchers need to be able to edit the donor cells using something like the CRISPR technology, so that the vessels can integrate and be accepted by the patient’s body.

We are still not at that step, but we are one step closer,” Karande said.

“This significant development highlights the vast potential of 3D bioprinting in precision medicine, where solutions can be tailored to specific situations and eventually to individuals,” said Deepak Vashishth, the director CBIS. “This is a perfect example of how engineers at Rensselaer are solving challenges related to human health.”

Karande said more work will need to be done to address the challenges associated with burn patients, which include the loss of nerve and vascular endings. But the grafts his team has created bring researchers closer to helping people with more discrete issues, like diabetic or pressure ulcers.

“For those patients, these would be perfect, because ulcers usually appear at distinct locations on the body and can be addressed with smaller pieces of skin,” Karande said. “Wound healing typically takes longer in diabetic patients, and this could also help to accelerate that process.”

Very unusually, I cannot find the full title for this paper. Here’s what I found,

Three Dimensional Bioprinting of a Vascularized and Perfusable Skin Graft Using Human Keratinocytes, Fibroblasts, Pericytes, and Endothelial Cells by Dr. Tânia Baltazar, Dr. Jonathan Merola, Miss Carolina Motter Catarino, Miss Catherine Bingchan Xie, Dr. Nancy Kirkiles-Smith, Dr. Vivian Lee, Miss Stéphanie Yuki Kolbeck Hotta, Dr. Guohao Dai, Dr. Xiaowei Xu, Dr. Frederico Castelo Ferreira, Dr. W Mark Saltzman, Dr. Jordan S Pober, and Prof. Pankaj Karande. Tissue Engineering Part A DOI: https://doi.org/10.1089/ten.TEA.2019.0201 Published Online: 1 Nov 2019

As noted earlier, this is behind a paywall.