Tag Archives: graphene oxide (GO)

Improving bacteria detection with the ‘unboil an egg’ machine

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Vortex Fluidic Device (VFD) is the technical name for the more familiarly known ‘unboil an egg machine’ and, these days, it’s being used in research to improve bacteria detection. A June 23, 2020 news item on Nanowerk announces the research (Note: A link has been removed),

The versatility of the Vortex Fluidic Device (VFD), a device that famously unboiled an egg, continues to impress, with the innovative green chemistry device created at Flinders University having more than 100 applications – including the creation of a new non-toxic fluorescent dye that detects bacteria harmful to humans.

Traditional fluorescent dyes to examine bacteria viability are toxic and suffer poor photostability – but using the VFD has enabled the preparation of a new generation of aggregation-induced emission dye (AIE) luminogens using graphene oxide (GO), thanks to collaborative research between Flinders University’s Institute for NanoScale Science and Technology and the Centre for Health Technologies, University of Technology Sydney.

Using the VFD to produce GO/AIE probes with the property of high fluorescence is without precedent – with the new GO/AIE nanoprobe having 1400% brighter high fluorescent performance than AIE luminogen alone (Materials Chemistry Frontiers, “Vortex fluidic enabling and significantly boosting light intensity of graphene oxide with aggregation induced emission luminogen”).

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A June 24, 2020 Flinders University [Australia] press release, which originated the news item, delves further into the work,

“It’s crucial to develop highly sensitive ways of detecting bacteria that pose a potential threat to humans at the early stage, so health sectors and governments can be informed promptly, to act quickly and efficiently,” says Flinders University researcher Professor Youhong Tang.

“Our GO/AIE nanoprobe will significantly enhance long-term tracking of bacteria to effectively control hospital infections, as well as developing new and more efficient antibacterial compounds.”

The VFD is a new type of chemical processing tool, capable of instigating chemical reactivity, enabling the controlled processing of materials such as mesoporous silica, and effective in protein folding under continuous flow, which is important in the pharmaceutical industry. It continues to impress researchers for its adaptability in green chemistry innovations.

“Developing such a deep understanding of bacterial viability is important to revise infection control policies and invent effective antibacterial compounds,” says lead author of the research, Dr Javad Tavakoli, a previous researcher from Professor Youhong Tang’s group, and now working at the University of Technology Sydney.

“The beauty of this research was developing a highly bright fluorescence dye based on graphene oxide, which has been well recognised as an effective fluorescence quenching material.”

The type of AIE luminogen was first developed in 2015 to enable long-term monitoring of bacterial viability, however, increasing its brightness to increase sensitivity and efficiency remained a difficult challenge. Previous attempts to produce AIE luminogen with high brightness proved very time-consuming, requires complex chemistry, and involves catalysts rendering their mass production expensive.

By comparison, the Vortex Fluidic Device allows swift and efficient processing beyond batch production and the potential for cost-effective commercialisation.

Increasing the fluorescent property of GO/AIE depends on the concentration of graphene oxide, the rotation speed of the VFD tube, and the water fraction in the compound – so preparing GO/AIE under the shear stress induced by the VFD’s high-speed rotating tube resulted in much brighter probes with significantly enhanced fluorescent intensities.

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

Vortex fluidic enabling and significantly boosting light intensity of graphene oxide with aggregation induced emission luminogen by Javad Tavakoli, Nikita Joseph, Clarence Chuah, Colin L. Raston and Youhong Tang. Mater. Chem. Front., [Materials Chemistry Frontiers] 2020, Advance Article DOI: https://doi.org/10.1039/D0QM00270D First published: 28 May 2020

This paper is behind a paywall.

I first marveled about the VFD (unboil an egg machine) in a March 16, 2016 posting.

Bacteria and graphene oxide as a basis for producing computers

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A July 10, 2019 news item on ScienceDaily announces a more environmentally friendly way to produce graphene leading to more environmentally friendly devices such as computers,

In order to create new and more efficient computers, medical devices, and other advanced technologies, researchers are turning to nanomaterials: materials manipulated on the scale of atoms or molecules that exhibit unique properties.

Graphene — a flake of carbon as thin as a single later of atoms — is a revolutionary nanomaterial due to its ability to easily conduct electricity, as well as its extraordinary mechanical strength and flexibility. However, a major hurdle in adopting it for everyday applications is producing graphene at a large scale, while still retaining its amazing properties.

In a paper published in the journal ChemOpen, Anne S. Meyer, an associate professor of biology at the University of Rochester [New York state, US], and her colleagues at Delft University of Technology in the Netherlands, describe a way to overcome this barrier. The researchers outline their method to produce graphene materials using a novel technique: mixing oxidized graphite with bacteria. Their method is a more cost-efficient, time-saving, and environmentally friendly way of producing graphene materials versus those produced chemically, and could lead to the creation of innovative computer technologies and medical equipment.

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A July 10, 2019 University of Rochester news release (also on EurekAlert), which originated the news item, provides details as to how this new technique for extracting graphene differs from the technique currently used,

Graphene is extracted from graphite, the material found in an ordinary pencil. At exactly one atom thick, graphene is the thinnest–yet strongest–two-dimensional material known to researchers. Scientists from the University of Manchester in the United Kingdom were awarded the 2010 Nobel Prize in Physics for their discovery of graphene; however, their method of using sticky tape to make graphene yielded only small amounts of the material.

“For real applications you need large amounts,” Meyer says. “Producing these bulk amounts is challenging and typically results in graphene that is thicker and less pure. This is where our work came in.”

In order to produce larger quantities of graphene materials, Meyer and her colleagues started with a vial of graphite. They exfoliated the graphite–shedding the layers of material–to produce graphene oxide (GO), which they then mixed with the bacteria Shewanella. They let the beaker of bacteria and precursor materials sit overnight, during which time the bacteria reduced the GO to a graphene material.

“Graphene oxide is easy to produce, but it is not very conductive due to all of the oxygen groups in it,” Meyer says. “The bacteria remove most of the oxygen groups, which turns it into a conductive material.”

While the bacterially-produced graphene material created in Meyer’s lab is conductive, it is also thinner and more stable than graphene produced chemically. It can additionally be stored for longer periods of time, making it well suited for a variety of applications, including field-effect transistor (FET) biosensors and conducting ink. FET biosensors are devices that detect biological molecules and could be used to perform, for example, real-time glucose monitoring for diabetics.

“When biological molecules bind to the device, they change the conductance of the surface, sending a signal that the molecule is present,” Meyer says. “To make a good FET biosensor you want a material that is highly conductive but can also be modified to bind to specific molecules.” Graphene oxide that has been reduced is an ideal material because it is lightweight and very conductive, but it typically retains a small number of oxygen groups that can be used to bind to the molecules of interest.

The bacterially produced graphene material could also be the basis for conductive inks, which could, in turn, be used to make faster and more efficient computer keyboards, circuit boards, or small wires such as those used to defrost car windshields. Using conductive inks is an “easier, more economical way to produce electrical circuits, compared to traditional techniques,” Meyer says. Conductive inks could also be used to produce electrical circuits on top of nontraditional materials like fabric or paper.

“Our bacterially produced graphene material will lead to far better suitability for product development,” Meyer says. “We were even able to develop a technique of ‘bacterial lithography’ to create graphene materials that were only conductive on one side, which can lead to the development of new, advanced nanocomposite materials.”

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

Creation of Conductive Graphene Materials by Bacterial Reduction Using Shewanella Oneidensis by Benjamin A. E. Lehner, Vera A. E. C. Janssen, Dr. Ewa M. Spiesz, Dominik Benz, Dr. Stan J. J. Brouns, Dr. Anne S. Meyer, Prof. Dr. Herre S. J. van der Zant. ChemistryOpen Volume 8, Issue 7 July 2019 Pages 888-895 DOI: https://doi.org/10.1002/open.201900186
First published: 04 July 2019

As you would expect given the journal’s title, this paper is open access.

Graphene and water (G20 Water commentary)

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Tim Harper’s, Chief Executive Officer (CEO) of G2O Water, July 13, 2015 commentary was published on Nanotechnology Now. Harper, a longtime figure in the nanotechnology community (formerly CEO of Cientifica, an emerging technologies consultancy and current member of the World Economic Forum, not unexpectedly focused on water,

In the 2015 World Economic Forum’s Global Risks Report survey participants ranked Water Crises as the biggest of all risks, higher than Weapons of Mass Destruction, Interstate Conflict and the Spread of Infectious Diseases (pandemics). Our dependence on the availability of fresh water is well documented, and the United Nations World Water Development Report 2015 highlights a 40% global shortfall between forecast water demand and available supply within the next fifteen years. Agriculture accounts for much of the demand, up to 90% in most of the world’s least-developed countries, and there is a clear relationship between water availability, health, food production and the potential for civil unrest or interstate conflict.

The looming crisis is not limited to water for drinking or agriculture. Heavy metals from urban pollution are finding their way into the aquatic ecosystem, as are drug residues and nitrates from fertilizer use that can result in massive algal blooms. To date, there has been little to stop this accretion of pollutants and in closed systems such as lakes these pollutants are being concentrated with unknown long term effects.

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Ten years ago, following discussions with former Israeli Prime Minister Shimon Peres, I organised a conference in Amsterdam called Nanowater to look at how nanotechnology could address global water issues. [emphasis mine] While the meeting raised many interesting points, and many companies proposed potential solutions, there was little subsequent progress.

Rather than a simple mix of one or two contaminants, most real world water can contain hundreds of different materials, and pollutants like heavy metals may be in the form of metal ions that can be removed, but are equally likely to be bound to other larger pieces of organic matter which cannot be simply filtered through nanopores. In fact the biggest obstacle to using nanotechnology in water treatment is the simple fact that small holes are easily blocked, and susceptibility to fouling means that most nanopore membranes quickly become barriers instead of filters.

Fortunately some recent developments in the ‘wonder material’ graphene may change the economics of water. One of the major challenges in the commercialisation of graphene is the ability to create large areas of defect-free material that would be suitable for displays or electronics, and this is a major research topic in Europe where the European Commission is funding graphene research to the tune of a billion euros. …

Tim goes on to describe some graphene-based solutions including a technology developed at the University of South Carolina, which is also mentioned in a July 16, 2015 G20 Water press release,

Fouling of nano/ultrafiltration membranes in oil/water separation is a longstanding issue and a major economic barrier for their widespread adoption. Currently membranes typically show severe fouling, resulting from the strong adhesion of oil on the membrane surface and/or oil penetration inside the membranes. This greatly degrades their performance and shortens service lifetime as well as increasing the energy usage.

G2O™s bio inspired approach uses graphene oxide (GO) for the fabrication of fully-recoverable membranes for high flux, antifouling oil/water separation via functional and structural mimicking of fish scales. The ultra-thin, amphiphilic, water-locking GO coating mimics the thin mucus layer covering fish scales, while the combination of corrugated GO flakes and intrinsic roughness of the porous supports successfully reproduces the hierarchical roughness of fish scales. Cyclic membrane performance evaluation tests revealed circa 100% membrane recovery by facile surface water flushing, establishing their excellent easy-to-recover capability.

The pore sizes can be tuned to specific applications such as water desalination, oil/water separation, storm water treatment and industrial waste water recovery. By varying the GO concentration in water, GO membranes with different thickness can be easily fabricated via a one-time filtration process.
G2O™s patented graphene oxide technology acts as a functional coating for modifying the surface properties of existing filter media resulting in:
Higher pure water flux;
High fouling resistance;
Excellent mechanical strength;
High chemical stability;
Good thermal stability;
Low cost.

We’re going through a water shortage here in Vancouver, Canada after a long spring season which distinguished itself with a lack of rain and the introduction of a heatwave extending into summer. It is by no means equivalent to the situation in many parts of the world but it does give even those of us who are usually waterlogged some insight into what it means when there isn’t enough water.

For more insight into water crises with a special focus on the Middle East (notice Harper mentioned Israel’s former Prime Minister Shimon Peres in his commentary), I have a Feb. 24, 2014 posting (Water desalination to be researched at Oman’s newly opened Nanotechnology Laboratory at Sultan Qaboos University) and a June 25, 2013 post (Nanotechnology-enabled water resource collaboraton between Israel and Chicago).

You can check out the World Economic Forum’s Outlook on the Global Agenda 2015 here.

The Outlook on the Global Agenda 2015 features an analysis of the Top 10 trends which will preoccupy our experts for the next 12-18 months as well as the key challenges facing the world’s regions, an overview of global leadership and governance, and the emerging issues that will define our future.

G20 Water can be found here.

Graphite research at Simon Fraser University (Vancouver, Canada) and NanoXplore’s (Montréal, Canada) graphene oxide production

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Graphite

Simon Fraser University (SFU) announced a partnership with Ontario’s Sheridan College and three Canadian companies (Terrella Energy Systems, Alpha Technologies, and Westport Innovations) in a research project investigating low-cost graphite thermal management products. From an April 9, 2015 SFU news release,

Simon Fraser University is partnering with Ontario’s Sheridan College, and a trio of Canadian companies, on research aimed at helping the companies to gain market advantage from improvements on low-cost graphite thermal management products.

 

Graphite is an advanced engineering material with key properties that have potential applications in green energy systems, automotive components and heating ventilating air conditioning systems.

 

The project combines expertise from SFU’s Laboratory for Alternative Energy Conversion with Sheridan’s Centre for Advanced Manufacturing and Design Technologies.

 

With $700,000 in funding from the Natural Sciences and Engineering Research Council’s (NSERC) College and Community Innovation program, the research will help accelerate the development and commercialization of this promising technology, says project lead Majid Bahrami, an associate professor in SFU’s School of Mechatronics Systems Engineering (MSE) at SFU’s Surrey campus.

 

The proposed graphite products take aim at a strategic $40 billion/year thermal management products market, Bahrami notes. 

 

Inspired by the needs of the companies, Bahrami says the project has strong potential for generating intellectual property, leading to advanced manufacturing processes as well as new, efficient graphite thermal products.

 

The companies involved include:

 

Terrella Energy Systems, which recently developed a roll-embossing process that allows high-volume, cost-effective manufacturing of micro-patterned, coated and flexible graphite sheets;

 

Alpha Technologies, a leading telecom/electronics manufacturer, which is in the process of developing next-generation ‘green’ cooling solutions for their telecom/electronics systems;

 

Westport Innovations, which is interested in integrating graphite heat exchangers in their natural gas fuel systems, such as heat exchangers for heavy-duty trucks.

 

Bahrami, who holds a Canada Research Chair in Alternative Energy Conversion Systems, expects the project will also lead to significant training and future business and employment opportunities in the manufacturing and energy industry, as well as the natural resource sector and their supply chain.

 

“This project leverages previous federal government investment into world-class testing equipment, and SFU’s strong industrial relationships and entrepreneurial culture, to realize collective benefits for students, researchers, and companies,” says Joy Johnson, SFU’s VP Research. “By working together and pooling resources, SFU and its partners will continue to generate novel green technologies and energy conversion solutions.”

 

Fast Facts:

  • The goal of the NSERC College and Community Innovation program is to increase innovation at the community and/or regional level by enabling Canadian colleges to increase their capacity to work with local companies, particularly small and medium-sized enterprises (SMEs).
  • Canada is the fifth largest exporter of raw graphite.
  • …

I have mentioned graphite here before. Generally, it’s in relation to graphite mining deposits in Ontario and Québec, which seem to have been of great interest as a source for graphene production. A Feb. 20, 2015 posting was the the latest of those mentions and, coincidentally, it features NanoXplore and graphene, the other topic noted in the head for this posting.

Graphene and NanoXplore

An April 17, 2015 news item on Azonano makes a production announcement,

Group NanoXplore Inc., a Montreal-based company specialising in the production and application of graphene and its derivative materials, announced today that it is producing Graphene Oxide in industrial quantities. The Graphene Oxide is being produced in the same 3 metric tonne per year facility used to manufacture NanoXplore’s standard graphene grades and derivative products such as a unique graphite-graphene composite suitable for anodes in Li-ion batteries.

An April 16, 2015 NanoXplore news release on MarketWired, which originated the news item, describes graphene oxide and its various uses,

Graphene Oxide (GO) is similar to graphene but with significant amounts of oxygen introduced into the graphene structure. GO, unlike graphene, can be readily mixed in water which has led people to use GO in thin films, water-based paints and inks, and biomedical applications. GO is relatively simple to synthesise on a lab scale using a modified Hummers’ method, but scale-up to industrial production is quite challenging and dangerous. This is because the Hummers’ method uses strong oxidizing agents in a highly exothermic reaction which produces toxic and explosive gas. NanoXplore has developed a completely new and different approach to producing GO based upon its proprietary graphene production platform. This novel production process is completely safe and environmentally friendly and produces GO in volumes ranging from kilogram to tonne quantities.

“NanoXplore’s ability to produce industrially useful quantities of Graphene Oxide in a safe and scalable manner is a game changer, said Dr. Soroush Nazarpour, President and CEO of NanoXplore. “Mixing graphene with standard industrially materials is the key to bringing it to industrial markets. Graphene Oxide mixes extremely well with all water based solutions, and we have received repeated customer requests for water soluble graphene over the last two years”.

It sounds exciting but it would be helpful (for someone like me, who’s ignorant about these things) to know the graphene oxide market’s size. This would help me to contextualize the excitement.

You can find out more about NanoXplore here.