Tag Archives: Macquarie University

Fission chips—using vinegar to produce ultraviolet (UV) light sensors for more efficient and flexible wearable devices?

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Thank you to whoever wrote this headline (I love wordplay), “Fission chips – How vinegar could revolutionize sensor processing” used for an August 28, 2024 news item on ScienceDaily,

Researchers at Macquarie University [Australia] have developed a new way to produce ultraviolet (UV) light sensors, which could lead to more efficient and flexible wearable devices.

The study, published in the journal Small in July [2024], shows how acetic acid vapour — essentially vinegar fumes — can rapidly improve the performance of zinc oxide nanoparticle-based sensors without using high-temperatures for processing.

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An August 23, 2024 Macquarie University press release (also on EurekAlert but published on August 28, 2024), which originated the news item, provides more detail about the new technique,

Co-author Professor Shujuan Huang, from the School of Engineering at Macquarie University, says: “We found by briefly exposing the sensor to vinegar vapour, adjoining particles of zinc oxide on the sensor’s surface would merge together, forming a bridge that could conduct energy.”

Joining zinc oxide nanoparticles together is a critical part of building tiny sensors, as it creates channels for electrons to flow through.

The research team found that their vapour method could make UV detectors 128,000 more responsive than untreated ones, and the sensors could still accurately detect UV light without interference, making them highly sensitive and reliable.

Associate Professor Noushin Nasiri, co-author on the paper and head of the Nanotech Laboratory at Macquarie University, says: “Usually, these sensors are processed in an oven, heated at high temperature for 12 hours or so, before they can operate or transmit any signal.”

But instead, the team found a simple chemical way to copy the effects of the heat process.

“We found a way to process these sensors at room temperature with a very cheap ingredient – vinegar. You just expose the sensor to vinegar vapour for five minutes, and that’s it – you have a working sensor,” she says.

To create the sensors, the researchers sprayed a zinc solution into a flame, producing a fine mist of zinc oxide nanoparticles that settled onto platinum electrodes. This formed a thin sponge-like film, which they then exposed to vinegar vapour for five to 20 minutes.

The vinegar vapour changed how the tiny particles in the film were arranged, helping the particles connect to each other, so electrons could flow through the sensor. At the same time, the particles stayed small enough to detect light effectively.

“These sensors are made of many, many tiny particles that need to be connected for the sensor to work,” says Associate Professor Nasiri.

“Until we treat them, the particles just sit next to each other, almost as if they have a wall around them, so when light creates an electrical signal in one particle, it can’t easily travel to the next particle. That’s why an untreated sensor doesn’t give us a good signal.”

The researchers went through intensive testing of different formulations before hitting on the perfect balance in their process.

“Water alone isn’t strong enough to make the particles join. But pure vinegar is too strong and destroys the whole structure,” says Professor Huang. “We had to find just the right mix.”

The study shows the best results came from sensors exposed to the vapour for around 15 minutes. Longer exposure times caused too many structural changes and worse performance.

“The unique structure of these highly porous nanofilms enables oxygen to penetrate deeply, so that the entire film is part of the sensing mechanism,” Professor Huang says.

The new room-temperature vapour technique has many advantages over current high-temperature methods. It allows the use of heat-sensitive materials and flexible bases, and is cheaper and better for the environment.

Associate Professor Nasiri says the process can easily be scaled up commercially.

“The sensor materials could be laid out on a rolling plate, passing through an enclosed environment with vinegar vapours, and be ready to use in less than 20 minutes.”

The process will be a real advantage in creating wearable UV sensors, which need to be flexible and to use very little power.

Associate Professor Nasiri says that this method for UV sensors could be used for other types of sensors too, using simple chemical vapour treatments instead of high-temperature sensor processing across a wide range of functional materials, nanostructures and bases or substrates.

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

Vapor-Tailored Nanojunctions in Ultraporous ZnO Nanoparticle Networks for Superior UV Photodetection by Jeff Huang, Xiaohu Chen, Shujuan Huang, Noushin Nasiri. Small DOI: https://doi.org/10.1002/smll.202402558 First published: 20 July 2024

This paper is open access.

Frog saunas

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Simple and successful: Dr Waddle’s team used bricks placed in sunny spots to provide hot shelters for green and golden bell frogs, pictured above, dubbing the experimental method as “mini med spas for frogs”. Photo: Dr Anthony Waddle

It seems one of the universities involved in this research was left out of the original news release and subsequent news coverage. First, there’s the original news as it was covered in June 2024 and then, you’ll find the July 2024 news release from the University of Arkansas.

A June 26, 2024 news item on phys.org announces a new approach to saving frogs from a fungus which is decimating frog species worldwide, Note: Links have been removed,

Macquarie University [Australia] researchers have used heat to develop a simple and effective way to help endangered frogs survive the devastating impacts of a pandemic sweeping multiple species

In collaboration with the University of Melbourne, researchers homed in on the fungal disease chytridiomycosis, which has already driven at least six amphib ian species to extinction in Australia and threatens dozens more worldwide.

The findings, published in the journal Nature on 26 June 2024, offer a potential lifeline for fast-declining populations like the green and golden bell frog (Litoria aurea), which has disappeared from more than 90% of its former native range in Australia.

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A shortened version of a Macquarie University press release on EurekAlert published June 26, 2024; reproduced here and which originated the news item, provides more detail about the fungus and the role frog saunas could play in their survival, Note: A link has been removed,

Dr Anthony Waddle, a Schmidt Science Fellow at Macquarie University’s Applied BioSciences and lead author of the study, says very few interventions address the impacts of the international spread of the disease-causing chytrid fungus (Batrachochytrium dendrobatidis or Bd).

“In the 25 years since chytrid was identified as a major cause of the global collapse of amphibian populations, our results are the first to provide a simple, inexpensive and widely applicable strategy to buffer frogs against this disease,” Dr Waddle says.

Chytridiomycosis (chytrid) typically establishes itself permanently once it spreads to a new environment and has caused greater damage to global biodiversity than any other recorded disease or invasive species.

Of chytrid-stricken species worldwide, 90 have gone extinct or are presumed extinct in the wild. Another 124 species have declined in number by more than 90 percent.

Senior author Professor Rick Shine, from Macquarie University’s School of Natural Sciences says this study has demonstrated a simple intervention which can easily scale up, potentially helping reduce the impact of the deadly chytrid pandemic.

“Chytrid isn’t going away, but our behavioural ecology intervention can help endangered amphibians co-exist with chytridiomycosis in their ecosystems,” Professor Shine says. 

The research team found artificial ‘hotspot’ shelters built from readily available materials, such as bricks and PVC greenhouses, can allow frogs to quickly ‘bake off’ infections with the chytrid fungus. 

When frogs shifted to hotspot shelters, chytrid infections were reduced significantly.
“The whole thing is like a mini med spa for frogs,” says Dr Waddle. 

“In these simple little hotspots, frogs can go and heat up their bodies to a temperature that destroys the infections. 

The study also showed that frogs who survive a chytrid infection can develop a form of acquired immunity, making them more resistant to future infections. 

“Lowering mortality rates and boosting their immunity to chytrid is the key to protecting amphibians from this disease, which is now endemic around the world,” says Dr Waddle.

Dr Waddle says these simple ‘hotspot’ shelters are easy to reproduce, and the strategy can easily be scaled up with community involvement.

Professor Lee Skerratt, Professorial Fellow in Wildlife Bioscience at the University of Melbourne, says: “This research has great potential to be extrapolated to other endangered frog species threatened by chytridiomycosis, and demonstrates the value of cross-disciplinary and cross-institutional collaboration in tackling this global problem.”

A June 27, 2024 Macquarie University press release by Fran Molloy, is an extended version on The Lighthouse – Macquarie University’s multi-media publishing platform – please credit when republishing) and is worth checking out for more details about the saunas and more photos,

Swab: Dr Waddle’s results showed frogs who survived a chytridiomycosis infection can also develop a form of acquired immunity, making them more resistant to future infections. Photo: Yorick Lambreghts

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

Hotspot shelters stimulate frog resistance to chytridiomycosis by Anthony W. Waddle, Simon Clulow, Amy Aquilina, Erin L. Sauer, Shannon W. Kaiser, Claire Miller, Jennifer A. Flegg, Patricia T. Campbell, Harrison Gallagher, Ivana Dimovski, Yorick Lambreghts, Lee Berger, Lee F. Skerratt & Richard Shine. Nature (2024) DOI: https://doi.org/10.1038/s41586-024-07582-y Published: 26 June 2024

This paper is behind a paywall.

University of Arkansas

From a July 29, 2024 University of Arkansas news release (also on EurekAlert), Note: Links have been removed,

As global diversity continues to decline due to a range of factors, amphibians have been particularly hard hit by infectious diseases. A pernicious fungal disease called chytridiomycosis, more commonly shortened to “chytrid,” has led to the extinction of 90 species of amphibians and has pushed another 500 species into decline.

New research, though, offers hope in the form of “frog saunas.” Imagine not a traditional wood sauna beloved by Finns and Estonians, but rather a large, sun-heated brick structure with cubby holes where frogs can find refuge from colder weather. During winter, chytrid hits frogs harder, and the researchers speculated that if green and golden bell frogs were given an opportunity to get warmer in artificial saunas, they would take it. It turns out not only would they take the opportunity, raising their body temperature helped them clear the infection as well.

Experiments were carried out in both lab and natural settings, where the frogs had both shaded and unshaded options and no inducement to access the saunas. But they took to the saunas like Finns in winter. The researchers also found that frogs that were initially infected and then fought off the infection after spending time in the sauna were significantly less likely to be reinfected. 

The paper, “Hotspot shelters stimulate frog resistance to chytridiomycosis,” was published in Nature and has received a great deal of attention, having been covered by The New York Times, Scientific American, Smithsonian Magazine, Science, and Popular Sciences. Of the 14 people listed as co-authors, 12 hail from Australia, where the research was conducted. The lone North American co-author is Erin Sauer, a postdoctoral fellow in biological sciences at the University of Arkansas. 

In fact, the team’s work on frog saunas was inspired by Sauer’s previous research into how amphibian thermoregulatory behavior influences resistance to chytrid. For that study, done in 2018, Sauer designed thermal gradients she could keep frogs in for longer periods of time while measuring their thermal preferences.  [emphasis mine]

In practical terms, this meant putting a Plexiglas lid on sections of aluminum gutter that had a heating element on one end and cooling element on the other, providing a range of temperatures in between the two ends. She ultimately found that species that preferred warmer temperatures were able to clear their infections when they hung out on the warmer parts of the thermal gradients. 

“Anthony Waddle, the lead author on the Nature paper, got in touch with me because he wanted to build my thermal gradients in Australia and replicate my study with green and golden bell frogs,” Sauer explained. “So, I helped him design his set up and experiment in 2020-2021, and then helped with the data analysis for the lab study.  

“Very similar to my 2018 study, we found that the green and golden bell frogs preferred warm temperatures and were able to better resist their chytrid infections at those warm temperatures. Anthony and his colleagues in Australia then applied the findings from the lab experiment to build the frog saunas and run the mesocosm experiment.”  [emphasis mine]

While the findings suggest that the general public can play a role in saving green and golden bell frogs from extinction by building low-cost saunas in gardens or wetlands, Sauer cautions that this will not help all species of frogs [emphasis mine].  

“My research has shown that while warm adapted species have better disease outcomes at warm temperatures, cold adapted species actually have worse outcomes at warm temperatures [emphasis mine],” Sauer said. “My colleagues and I have termed this phenomenon the ‘thermal mismatch hypothesis’ and did a global study testing our hypothesis across systems a few years ago that was published in Science. So, unfortunately, the frog saunas won’t work for all species but work beautifully for the warm-preferring green and golden bell frogs.”  

Given that frogs in the region where I live are cold adapted, it’s good to know that frog saunas won’t be helpful to them. Thank you Dr. Sauer.

Ancient Namibian gemstone could be key to new light-based quantum computers

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Researchers in Scotland, the US, Australia, and Denmark have a found a solution to a problem with creating light-based computers according to an April 15, 2022 news item on phys.org,

A special form of light made using an ancient Namibian gemstone could be the key to new light-based quantum computers, which could solve long-held scientific mysteries, according to new research led by the University of St Andrews.

The research, conducted in collaboration with scientists at Harvard University in the US, Macquarie University in Australia and Aarhus University in Denmark and published in Nature Materials, used a naturally mined cuprous oxide (Cu2O) gemstone from Namibia to produce Rydberg polaritons, the largest hybrid particles of light and matter ever created.

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Cuprous oxide – the mined crystal from Namibia used for making Rydberg polaritons. Courtesy: University of St. Andrews

An April 15, 2022 University of St. Andrews press release, which originated the news item, describes Rydberg polaritons and explains why they could be the key to light-based quantum computing,

Rydberg polaritons switch continually from light to matter and back again. In Rydberg polaritons, light and matter are like two sides of a coin, and the matter side is what makes polaritons interact with each other.

This interaction is crucial because this is what allows the creation of quantum simulators, a special type of quantum computer, where information is stored in quantum bits. These quantum bits [qubits], unlike the binary bits in classical computers that can only be 0 or 1, can take any value between 0 and 1. They can therefore store much more information and perform several processes simultaneously.

This capability could allow quantum simulators to solve important mysteries of physics, chemistry and biology, for example, how to make high-temperature superconductors for highspeed trains, how cheaper fertilisers could be made potentially solving global hunger, or how proteins fold making it easier to produce more effective drugs.

Project lead Dr Hamid Ohadi, of the School of Physics and Astronomy at the University of St Andrews, said: “Making a quantum simulator with light is the holy grail of science. We have taken a huge leap towards this by creating Rydberg polaritons, the key ingredient of it.”

To create Rydberg polaritons, the researchers trapped light between two highly reflective mirrors. A cuprous oxide crystal from a stone mined in Namibia was then thinned and polished to a 30-micrometer thick slab (thinner than a strand of human hair) and sandwiched between the two mirrors to make Rydberg polaritons 100 times larger than ever demonstrated before.

One of the leading authors Dr Sai Kiran Rajendran, of the School of Physics and Astronomy at the University of St Andrews, said: “Purchasing the stone on eBay was easy. The challenge was to make Rydberg polaritons that exist in an extremely narrow colour range.”

The team is currently further refining these methods in order to explore the possibility of making quantum circuits, which are the next ingredient for quantum simulators.

The research was funded by UK Engineering and Physical Sciences Research Council (EPSRC).

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

Rydberg exciton–polaritons in a Cu2O microcavity by Konstantinos Orfanakis, Sai Kiran Rajendran, Valentin Walther, Thomas Volz, Thomas Pohl & Hamid Ohadi. Nature Materials (2022) DOI: DOIhttps://doi.org/10.1038/s41563-022-01230-4 Published: 14 April 2022

This paper is behind a paywall.

Finding killer bacteria with quantum dots and a smartphone

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An August 5, 2019 news item on Nanowerk announces a new technology for detecting killer bacteria (Note: A link has been removed),

A combination of off-the-shelf quantum dots and a smartphone camera soon could allow doctors to identify antibiotic-resistant bacteria in just 40 minutes, potentially saving patient lives.

Staphylococcus aureus (golden staph), is a common form of bacterium that causes serious and sometimes fatal conditions such as pneumonia and heart valve infections. Of particular concern is a strain that does not respond to methicillin, the antibiotic of first resort, and is known as methicillin-resistant S. aureus, or MRSA.

Recent reports estimate that 700 000 deaths globally could be attributed to antimicrobial resistance, such as methicillin-resistance. Rapid identification of MRSA is essential for effective treatment, but current methods make it a challenging process, even within well-equipped hospitals.

Soon, however, that may change, using nothing except existing technology.

Researchers from Macquarie University and the University of New South Wales, both in Australia, have demonstrated a proof-of-concept device that uses bacterial DNA to identify the presence of Staphylococcus aureus positively in a patient sample – and to determine if it will respond to frontline antibiotics.

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An August 12,2019 Macquarie University press release (also on EurekAlert but published August 4, 2019), which originated the news item, delves into the work,

In a paper published in the international peer-reviewed journal Sensors and Actuators B: Chemical the Macquarie University team of Dr Vinoth Kumar Rajendran, Professor Peter Bergquist and Associate Professor Anwar Sunna with Dr Padmavathy Bakthavathsalam (UNSW) reveal a new way to confirm the presence of the bacterium, using a mobile phone and some ultra-tiny semiconductor particles known as quantum dots.

“Our team is using Synthetic Biology and NanoBiotechnology to address biomedical challenges. Rapid and simple ways of identifying the cause of infections and starting appropriate treatments are critical for treating patients effectively,” says Associate Professor Anwar Sunna, head of the Sunna Lab at Macquarie University.

“This is true in routine clinical situations, but also in the emerging field of personalised medicine.”

The researchers’ approach identifies the specific strain of golden staph by using a method called convective polymerase chain reaction (or cPCR). This is a derivative of a widely -employed technique in which a small segment of DNA is copied thousands of times, creating multiple samples suitable for testing.

Vinoth Kumar and colleagues then subject the DNA copies to a process known as lateral flow immunoassay – a paper-based diagnostic tool used to confirm the presence or absence of a target biomarker. The researchers use probes fitted with quantum dots to detect two unique genes, that confirms the presence of methicillin resistance in golden staph

A chemical added at the PCR stage to the DNA tested makes the sample fluoresce when the genes are detected by the quantum dots – a reaction that can be captured easily using the camera on a mobile phone.

The result is a simple and rapid method of detecting the presence of the bacterium, while simultaneously ruling first-line treatment in or out.

Although currently at proof-of-concept stage, the researchers say their system which is powered by a simple battery is suitable for rapid detection in different settings.

“We can see this being used easily not only in hospitals, but also in GP clinics and at patient bedsides,” says lead author, Macquarie’s Vinoth Kumar Rajendran.

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

Smartphone detection of antibiotic resistance using convective PCR and a lateral flow assay by Vinoth Kumar Rajendran, Padmavathy Bakthavathsalam, Peter L.Bergquist, Anwar Sunna. Sensors and Actuators B: Chemical Volume 298, 1 November 2019,126849 DOI: https://doi.org/10.1016/j.snb.2019.126849 Available online 23 July 2019

This paper is behind a paywall.

Luminescent upconversion nanoparticles could make imaging more efficient

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Researchers at the University of Adelaide (Australia) have found a way to embed luminiscent nanoparticles in glass, according to a June 8, 2016 news item on Nanotechnology,

This new “hybrid glass” successfully combines the properties of these special luminescent (or light-emitting) nanoparticles with the well-known aspects of glass, such as transparency and the ability to be processed into various shapes including very fine optical fibres.

The research, in collaboration with Macquarie University and University of Melbourne, has been published online in the journal Advanced Optical Materials.

A June 7, 2016 University of Adelaide press release (also on EurekAlert), which originated the news item, offers more detail,

“These novel luminescent nanoparticles, called upconversion nanoparticles, have become promising candidates for a whole variety of ultra-high tech applications such as biological sensing, biomedical imaging and 3D volumetric displays,” says lead author Dr Tim Zhao, from the University of Adelaide’s School of Physical Sciences and Institute for Photonics and Advanced Sensing (IPAS).

“Integrating these nanoparticles into glass, which is usually inert, opens up exciting possibilities for new hybrid materials and devices that can take advantage of the properties of nanoparticles in ways we haven’t been able to do before. For example, neuroscientists currently use dye injected into the brain and lasers to be able to guide a glass pipette to the site they are interested in. If fluorescent nanoparticles were embedded in the glass pipettes, the unique luminescence of the hybrid glass could act like a torch to guide the pipette directly to the individual neurons of interest.”

Although this method was developed with upconversion nanoparticles, the researchers believe their new ‘direct-doping’ approach can be generalised to other nanoparticles with interesting photonic, electronic and magnetic properties. There will be many applications – depending on the properties of the nanoparticle.

“If we infuse glass with a nanoparticle that is sensitive to radiation and then draw that hybrid glass into a fibre, we could have a remote sensor suitable for nuclear facilities,” says Dr Zhao.

To date, the method used to integrate upconversion nanoparticles into glass has relied on the in-situ growth of the nanoparticles within the glass.

“We’ve seen remarkable progress in this area but the control over the nanoparticles and the glass compositions has been limited, restricting the development of many proposed applications,” says project leader Professor Heike Ebendorff-Heideprem, Deputy Director of IPAS.

“With our new direct doping method, which involves synthesizing the nanoparticles and glass separately and then combining them using the right conditions, we’ve been able to keep the nanoparticles intact and well dispersed throughout the glass. The nanoparticles remain functional and the glass transparency is still very close to its original quality. We are heading towards a whole new world of hybrid glass and devices for light-based technologies.”

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

Upconversion Nanocrystal-Doped Glass: A New Paradigm for Photonic Materials by Jiangbo Zhao, Xianlin Zheng, Erik P. Schartner, Paul Ionescu, Run Zhang, Tich-Lam Nguyen, Dayong Jin, and Heike Ebendorff-Heidepriem. Advanced Optical Materials DOI: 10.1002/adom.201600296 Version of Record online: 30 MAY 2016

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Nanodiamonds and a broken heart

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Nanowerk’s March 3, 2013 news item highlights some research with biomedical applications taking place in Australia,

Researchers at Macquarie University have been perfecting a technique that may help see nanodiamonds used in biomedical applications. PhD student Jana Say has been working on processing the raw diamonds so that they might be used as a tag for biological molecules.

“We are working with nanodiamonds to process them so that they are stable enough to be used as a probe for single-molecule interactions. As diamonds are made from carbon, they are non-toxic which makes them advantageous for many biological applications over other nanoparticles,” says Say.

The Macquarie University Feb. 13, 2013 news release, which originated the Nanowerk news item, provides more detail,

The processing technique has already contributed to the success of research projects that have used the diamonds. Working with an international team, Say’s diamonds were able to be optically trapped and manipulated in three-dimensions – this first time this has been achieved.

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The diamonds themselves are incredibly small, 5000 times smaller than a human hair, and so the real strength in Say’s technique is her ability to consistently produce stable samples.

“The real challenge is reliably producing the same sample. It’s a very repetitive and involved process to prepare and characterise these diamonds,” she says.

Say, under the supervision of Dr Louise Brown of the Department of Chemistry and Biomolecular Sciecnes, has plans to continue to develop these diamonds and collaborate with other researchers to explore their full potential.

“Jana’s work is incredibly important,” says Dr Brown. “These diamonds were recently used in a project which won a Macquarie University research excellence award for demonstrating that nanodiamonds can be isolated and made to emit light. With this work, we continue to make real breakthroughs in this area and are contributing to the long term goals in ultrasensitive imaging and sensing technologies.”

For anyone who’s interested, here’s a citation and link to the research paper,

Three-dimensional optical manipulation of a single electron spin by Michael Geiselmann, Mathieu L. Juan, Jan Renger, Jana M. Say, Louise J. Brown,  F. Javier García de Abajo, Frank Koppens & Romain Quidant. Nature Nanotechnology (2013) doi:10.1038/nnano.2012.259 Published online 10 February 2013

The article is behind a paywall. One final comment, I very much enjoyed the fanciful title for the news release about this work, Diamonds may mend a broken heart: Researchers perfect nanodiamonds for use in biomedical applications.