skip to content

Department of Physics

The Cavendish Laboratory
 
Subscribe to Physics News feed
News from the Cavendish Laboratory.
Updated: 8 min 14 sec ago

Gone fishing: highly accurate test for common respiratory viruses uses DNA as ‘bait’

Mon, 16/01/2023 - 16:00

The test uses DNA ‘nanobait’ to detect the most common respiratory viruses – including influenza, rhinovirus, RSV and COVID-19 – at the same time. In comparison, PCR (polymerase chain reaction) tests, while highly specific and highly accurate, can only test for a single virus at a time and take several hours to return a result.

While many common respiratory viruses have similar symptoms, they require different treatments. By testing for multiple viruses at once, the researchers say their test will ensure patients get the right treatment quickly and could also reduce the unwarranted use of antibiotics.

In addition, the tests can be used in any setting, and can be easily modified to detect different bacteria and viruses, including potential new variants of SARS-CoV-2, the virus which causes COVID-19. The results are reported in the journal Nature Nanotechnology.

The winter cold, flu and RSV season has arrived in the northern hemisphere, and healthcare workers must make quick decisions about treatment when patients show up in their hospital or clinic.

“Many respiratory viruses have similar symptoms but require different treatments: we wanted to see if we could search for multiple viruses in parallel,” said Filip Bošković from Cambridge’s Cavendish Laboratory, the paper’s first author. “According to the World Health Organization, respiratory viruses are the cause of death for 20% of children who die under the age of five. If you could come up with a test that could detect multiple viruses quickly and accurately, it could make a huge difference.”

For Bošković, the research is also personal: as a young child, he was in hospital for almost a month with a high fever. Doctors could not figure out the cause of his illness until a PCR machine became available.

“Good diagnostics are the key to good treatments,” said Bošković, who is a PhD student at St John’s College, Cambridge. “People show up at hospital in need of treatment and they might be carrying multiple different viruses, but unless you can discriminate between different viruses, there is a risk patients could receive incorrect treatment.”

PCR tests are powerful, sensitive and accurate, but they require a piece of genome to be copied millions of times, which takes several hours.

The Cambridge researchers wanted to develop a test that uses RNA to detect viruses directly, without the need to copy the genome, but with high enough sensitivity to be useful in a healthcare setting.

“For patients, we know that rapid diagnosis improves their outcome, so being able to detect the infectious agent quickly could save their life,” said co-author Professor Stephen Baker, from the Cambridge Institute of Therapeutic Immunology and Infectious Disease. “For healthcare workers, such a test could be used anywhere, in the UK or in any low- or middle-income setting, which helps ensure patients get the correct treatment quickly and reduce the use of unwarranted antibiotics.”

The researchers based their test on structures built from double strands of DNA with overhanging single strands. These single strands are the ‘bait’: they are programmed to ‘fish’ for specific regions in the RNA of target viruses. The nanobaits are then passed through very tiny holes called nanopores. Nanopore sensing is like a ticker tape reader that transforms molecular structures into digital information in milliseconds. The structure of each nanobait reveals the target virus or its variant.

The researchers showed that the test can easily be reprogrammed to discriminate between viral variants, including variants of the virus that causes COVID-19. The approach enables near 100% specificity due to the precision of the programmable nanobait structures.

“This work elegantly uses new technology to solve multiple current limitations in one go,” said Baker. “One of the things we struggle with most is the rapid and accurate identification of the organisms causing the infection. This technology is a potential game-changer; a rapid, low-cost diagnostic platform that is simple and can be used anywhere on any sample.”

A patent on the technology has been filed by Cambridge Enterprise, the University’s commercialisation arm, and co-author Professor Ulrich Keyser has co-founded a company, Cambridge Nucleomics, focused on RNA detection with single-molecule precision.

“Nanobait is based on DNA nanotechnology and will allow for many more exciting applications in the future,” said Keyser, who is based at the Cavendish Laboratory. “For commercial applications and roll-out to the public we will have to convert our nanopore platform into a hand-held device.”

“Bringing together researchers from medicine, physics, engineering and chemistry helped us come up with a truly meaningful solution to a difficult problem,” said Bošković, who received a 2022 PhD award from Cambridge Society for Applied Research for this work.

The research was supported in part by the European Research Council, the Winton Programme for the Physics of Sustainability, St John’s College, UK Research and Innovation (UKRI), Wellcome, and the National Institute for Health and Care Research (NIHR) Cambridge Biomedical Research Centre.

Reference:
Filip Bošković et al. ‘Simultaneous identification of viruses and viral variants with programmable DNA nanobait.’ Nature Nanotechnology (2022). DOI: 10.1038/s41565-022-01287-x

A new test that ‘fishes’ for multiple respiratory viruses at once using single strands of DNA as ‘bait’, and gives highly accurate results in under an hour, has been developed by Cambridge researchers.

Good diagnostics are the key to good treatmentsFilip BoškovićNatalia Gdovskaia via Getty ImagesDoctor examining a patient


The text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright ©University of Cambridge and licensors/contributors as identified.  All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Webb telescope reaches new milestone in its search for distant galaxies

Fri, 09/12/2022 - 14:50

An international team of astronomers, including scientists at the Universities of Cambridge, Hertfordshire and Oxford, has reported the discovery of the earliest galaxies ever confirmed in our Universe.

Using data from the James Webb Space Telescope (JWST), scientists have confirmed observations of galaxies dating back to the earliest days of the Universe, less than 350 million years after the Big Bang – when the Universe was just 2% of its current age.

Images from JWST had previously suggested possible candidates for such early galaxies. Now, their age has been confirmed using long spectroscopic observations, which measure light to determine the speed and composition of objects in space.

These observations have revealed distinctive patterns in the tiny amount of light coming from these incredibly faint galaxies, allowing scientists to establish that the light they are emitting has taken 13.4 billion years to reach us, and corroborating their status as some of the earliest galaxies ever observed.

Scientists can also now confirm that two of these galaxies are further away than any observations made by the Hubble telescope – underlining JWST’s incredible power and ability to detect never-before-seen parts of the earliest Universe.

“It was crucial to prove that these galaxies do indeed inhabit the early Universe, as it’s very possible for closer galaxies to masquerade as very distant galaxies,” said Dr Emma Curtis-Lake from the University of Hertfordshire, lead author on one of two papers on the findings. “Seeing the spectrum revealed as we hoped, confirming these galaxies as being at the true edge of our view, some further away than Hubble could see – it is a tremendously exciting achievement for the mission!”

The findings have been achieved by an international collaboration of more than 80 astronomers from ten countries via the JWST Advanced Deep Extragalactic Survey (JADES) programme. The team were allocated just over a month of observation on the telescope, using the two on-board instruments: the Near-Infrared Spectrograph (NIRSpec) and the Near-Infrared Camera (NIRCam). These instruments were developed with the primary purpose of investigating the earliest and faintest galaxies.

“It is hard to understand galaxies without understanding the initial periods of their development,” said Dr Sandro Tacchella from Cambridge’s Cavendish Laboratory and Kavli Institute for Cosmology, co-lead author on the second paper. “Much as with humans, so much of what happens later depends on the impact of these early generations of stars. So many questions about galaxies have been waiting for the transformative opportunity of Webb, and we’re thrilled to be able to play a part in revealing this story.”

“For the first time, we have discovered galaxies only 350 million years after the big bang, and we can be absolutely confident of their fantastic distances,” said Brant Robertson from the University of California Santa Cruz, co-lead author on the second paper. “To find these early galaxies in such stunningly beautiful images is a special experience.”

Across 10 days of their observation time, the JADES team of astronomers focused on a small patch of sky in and around Hubble Space Telescope’s Ultra Deep Field, which for over 20 years has been a favourite of astronomers and has been analysed at the limit of nearly every large telescope to have existed. However, with JWST, the team were able to observe in nine different infrared wavelength ranges, providing an exquisitely sharp and sensitive picture of the field. The image reveals nearly 100,000 galaxies, each billions of light years away, in a pinprick of the sky equivalent to looking at a mobile phone screen across a football field.

The very earliest galaxies were identifiable by their distinctive banded colours, visible in infrared light but invisible in other wavelengths. In one rare continuous 28-hour observation window, the Near-Infrared Spectrograph was used to spread out the light emitting from each galaxy into a rainbow spectrum. This allowed astronomers to measure the amount of light received at each wavelength and study the unique light patterns created by the properties of the gas and stars within each galaxy.

Crucially, four of the galaxies were revealed to originate earlier in the Universe than any previous observations.

“Our observations suggest that the formation of the first stars and galaxies started very early in the history of the Universe,” said Professor Andrew Bunker from the University of Oxford.

“This is a major leap forward in our understanding of how the first galaxies formed,” said Professor Roberto Maiolino from Cambridge’s Cavendish Laboratory and Kavli Institute for Cosmology, co-author on one of the two papers. “We have been able to dissect the light coming from these galaxies in the very early universe and, for the first time, characterise in detail their properties. It’s really fascinating and intriguing to discover how young these systems were and that stellar processes hadn’t yet managed to pollute these galaxies with chemical elements heavier than helium.”

Astronomers in the JADES team now plan to focus on another area of the sky to conduct further spectroscopy and imaging, hoping to reveal more about the earliest origins of our Universe and how these first galaxies evolve with cosmic time.

More information about the findings can be found in a newly-published NASA blog. Pre-prints of the team’s two papers, which have not yet been peer-reviewed, are available online.

The James Webb Space Telescope is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency). Sandro Tacchella is a Fellow of St Edmund’s College, Cambridge.

Adapted from a University of Hertfordshire media release.

New findings confirm that JWST has surpassed the Hubble telescope in its ability to observe the early Universe

So many questions about galaxies have been waiting for the transformative opportunity of Webb, and we’re thrilled to be able to play a part in revealing this storySandro TacchellaNASA, ESA, CSA, M. Zamani (ESA/Webb)This image taken by the James Webb Space Telescope highlights the region of study by the JWST Advanced Deep Extragalactic Survey (JADES).


The text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright ©University of Cambridge and licensors/contributors as identified.  All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Non-detection of key signal allows astronomers to determine what the first galaxies were – and weren’t – like

Mon, 28/11/2022 - 16:00

Using data from India’s SARAS3 radio telescope, researchers led by the University of Cambridge were able to look at the very early Universe – just 200 million years after the Big Bang – and place limits on the mass and energy output of the first stars and galaxies.

Counterintuitively, the researchers were able to place these limits on the earliest galaxies by not finding the signal they had been looking for, known as the 21-centimetre hydrogen line.

This non-detection allowed the researchers to make other determinations about the cosmic dawn, placing restraints on the first galaxies, and enabling them to rule out scenarios including galaxies that were inefficient heaters of cosmic gas and efficient producers of radio emissions.

While we cannot yet directly observe these early galaxies, the results, reported in the journal Nature Astronomy, represent an important step in understanding how our Universe transitioned from mostly empty to one full of stars.

Understanding the early Universe, when the first stars and galaxies formed, is one of the major goals of new observatories. The results obtained using the SARAS3 data are a proof-of-concept study that paves the way to understanding this period in the development of the Universe.

The SKA project – involving two next-generation telescopes due to be completed by the end of the decade – will likely be able to make images of the early Universe, but for current telescopes, the challenge is to detect the cosmological signal of the first stars re-radiated by thick hydrogen clouds.

This signal is known as the 21-centimetre line – a radio signal produced by hydrogen atoms in the early Universe. Unlike the recently launched JWST, which will be able to directly image individual galaxies in the early Universe, studies of the 21-centimetre line, made with radio telescopes such as the Cambridge-led REACH (Radio Experiment for the Analysis of Cosmic Hydrogen), can tell us about entire populations of even earlier galaxies. The first results are expected from REACH early in 2023.

To detect the 21-centimetre line, astronomers look for a radio signal produced by hydrogen atoms in the early Universe, affected by light from the first stars and the radiation behind the hydrogen fog. Earlier this year, the same researchers developed a method that they say will allow them to see through the fog of the early universe and detect light from the first stars. Some of these techniques have been already put to practice in the current study.

In 2018, another research group operating the EDGES experiment published a result that hinted at a possible detection of this earliest light. The reported signal was unusually strong compared to what is expected in the simplest astrophysical picture of the early Universe. Recently, the SARAS3 data disputed this detection: the EDGES result is still awaiting confirmation from independent observations.

In a re-analysis of the SARAS3 data, the Cambridge-led team tested a variety of astrophysical scenarios which could potentially explain the EDGES result, but they did not find a corresponding signal. Instead, the team was able to place some limits on properties of the first stars and galaxies.

The results of the SARAS3 analysis are the first time that radio observations of the averaged 21-centimetre line have been able to provide an insight to the properties of the first galaxies in the form of limits of their main physical properties.

Working with collaborators in India, Australia and Israel, the Cambridge team used data from the SARAS3 experiment to look for signals from cosmic dawn, when the first galaxies formed. Using statistical modelling techniques, the researchers were not able to find a signal in the SARAS3 data.

"We were looking for a signal with a certain amplitude,” said Harry Bevins, a PhD student from Cambridge’s Cavendish Laboratory and the paper’s lead author. “But by not finding that signal, we can put a limit on its depth. That, in turn, begins to inform us about how bright the first galaxies were.”

“Our analysis showed that the hydrogen signal can inform us about the population of first stars and galaxies,” said co-lead author Dr Anastasia Fialkov from Cambridge’s Institute of Astronomy. “Our analysis places limits on some of the key properties of the first sources of light including the masses of the earliest galaxies and the efficiency with which these galaxies can form stars. We also address the question of how efficiently these sources emit X-ray, radio and ultraviolet radiation.”

“This is an early step for us in what we hope will be a decade of discoveries about how the Universe transitioned from darkness and emptiness to the complex realm of stars, galaxies and other celestial objects we can see from Earth today,” said Dr Eloy de Lera Acedo from Cambridge’s Cavendish Laboratory, who co-led the research.

The observational study, the first of its kind in many respects, excludes scenarios in which the earliest galaxies were both more than a thousand times as bright as present galaxies in their radio-band emission and were poor heaters of hydrogen gas.

“Our data also reveals something which has been hinted at before, which is that the first stars and galaxies could have had a measurable contribution to the background radiation that appeared as a result of the Big Bang and which has been travelling towards us ever since,” said de Lera Acedo, “We are also establishing a limit to that contribution.”

“It’s amazing to be able to look so far back in time – to just 200 million years after the Big Bang- and be able to learn about the early Universe,” said Bevins.

The research was supported in part by the Science and Technology Facilities Council (STFC), part of UK Research & Innovation (UKRI), and the Royal Society. The Cambridge authors are all members of the Kavli Institute for Cosmology in Cambridge.

 

Reference:
H T J Bevins et al. ‘Astrophysical constraints from the SARAS 3 non-detection of the cosmic dawn sky-averaged 21-cm signal.’ Nature Astronomy (2022). DOI: 10.1038/s41550-022-01825-6

Researchers have been able to make some key determinations about the first galaxies to exist, in one of the first astrophysical studies of the period in the early Universe when the first stars and galaxies formed, known as the cosmic dawn.

This is an early step for us in what we hope will be a decade of discoveries about how the Universe transitioned from darkness and emptiness to the complex realm of stars and galaxies we can see todayEloy de Lera AcedoNASA GoddardEarly galaxies capture by the NASA/ESA Hubble Telescope


The text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright ©University of Cambridge and licensors/contributors as identified.  All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

YesLicence type: Public Domain

Watching lithium in real time could improve performance of EV battery materials

Fri, 14/10/2022 - 14:46

The team, led by the University of Cambridge, tracked the movement of lithium ions inside a promising new battery material in real time.

It had been assumed that the mechanism by which lithium ions are stored in battery materials is uniform across the individual active particles. However, the Cambridge-led team found that during the charge-discharge cycle, lithium storage is anything but uniform.

When the battery is near the end of its discharge cycle, the surfaces of the active particles become saturated by lithium while their cores are lithium deficient. This results in the loss of reusable lithium and a reduced capacity.

The research, funded by the Faraday Institution, could help improve existing battery materials and could accelerate the development of next-generation batteries. The results are published in Joule.

Electrical vehicles (EVs) are vital in the transition to a zero-carbon economy. Most electric vehicles on the road today are powered by lithium-ion batteries, due in part to their high energy density.

However, as EV use becomes more widespread, the push for longer ranges and faster charging times means that current battery materials need to be improved, and new materials need to be identified.

Some of the most promising of these materials are state-of-the-art positive electrode materials known as layered lithium nickel-rich oxides, which are widely used in premium EVs. However, their working mechanisms, particularly lithium-ion transport under practical operating conditions, and how this is linked to their electrochemical performance, are not fully understood, so we cannot yet obtain maximum performance from these materials.

By tracking how light interacts with active particles during battery operation under a microscope, the researchers observed distinct differences in lithium storage during the charge-discharge cycle in nickel-rich manganese cobalt oxide (NMC).

“This is the first time that this non-uniformity in lithium storage has been directly observed in individual particles,” said co-first author Alice Merryweather, from Cambridge’s Yusuf Hamied Department of Chemistry. “Real time techniques like ours are essential to capture this while the battery is cycling.”

Combining the experimental observations with computer modelling, the researchers found that the non-uniformity originates from drastic changes to the rate of lithium-ion diffusion in NMC during the charge-discharge cycle. Specifically, lithium ions diffuse slowly in fully lithiated NMC particles, but the diffusion is significantly enhanced once some lithium ions are extracted from these particles.

“Our model provides insights into the range over which lithium-ion diffusion in NMC varies during the early stages of charging,” said co-first author Dr Shrinidhi Pandurangi from Cambridge’s Department of Engineering. “Our model predicted lithium distributions accurately and captured the degree of heterogeneity observed in experiments. These predictions are key to understanding other battery degradation mechanisms such as particle fracture.”

Importantly, the lithium heterogeneity seen at the end of discharge establishes one reason why nickel-rich cathode materials typically lose around ten percent of their capacity after the first charge-discharge cycle.

“This is significant, considering one industrial standard that is used to determine whether a battery should be retired or not is when it has lost 20 percent of its capacity,” said co-first author Dr Chao Xu, from ShanghaiTech University, who completed the research while based at Cambridge.

The researchers are now seeking new approaches to increase the practical energy density and lifetime of these promising battery materials.

The research was supported in part by the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation (UKRI). Alice Merryweather is jointly supervised by Professor Dame Clare Grey and Dr Akshay Rao, who are both co-authors on the current paper.  

Reference:
Chao Xu et al. ‘Operando visualization of kinetically induced lithium heterogeneities in single-particle layered Ni-rich cathodes.’ Joule (2022). DOI: 10.1016/j.joule.2022.09.008

Researchers have found that the irregular movement of lithium ions in next-generation battery materials could be reducing their capacity and hindering their performance.

Andrew Roberts via UnsplashElectric car charging


The text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright ©University of Cambridge and licensors/contributors as identified.  All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes