̽��ֱ�� of Cambridge - Cambridge Trust

Solar-powered device captures carbon dioxide from air to make sustainable fuel

sc604 — Thu, 13 Feb 2025 10:00:00 +0000

̽��ֱ��researchers, from the ̽��ֱ�� of Cambridge, say their solar-powered reactor could be used to make fuel to power cars and planes, or the many chemicals and pharmaceuticals products we rely on. It could also be used to generate fuel in remote or off-grid locations.

Unlike most carbon capture technologies, the reactor developed by the Cambridge researchers does not require fossil-fuel-based power, or the transport and storage of carbon dioxide, but instead converts atmospheric CO2 into something useful using sunlight. ̽��ֱ��results are reported in the journal Nature Energy.

Carbon Capture and Storage (CCS) has been touted as a possible solution to the climate crisis, and has recently received £22bn in funding from the UK government. However, CCS is energy-intensive and there are concerns about the long-term safety of storing pressurised CO2 deep underground, although safety studies are currently being carried out.

“Aside from the expense and the energy intensity, CCS provides an excuse to carry on burning fossil fuels, which is what caused the climate crisis in the first place,” said Professor Erwin Reisner, who led the research. “CCS is also a non-circular process, since the pressurised CO2 is, at best, stored underground indefinitely, where it’s of no use to anyone.”

“What if instead of pumping the carbon dioxide underground, we made something useful from it?” said first author Dr Sayan Kar from Cambridge’s Yusuf Hamied Department of Chemistry. “CO2 is a harmful greenhouse gas, but it can also be turned into useful chemicals without contributing to global warming.”

̽��ֱ��focus of Reisner’s research group is the development of devices that convert waste, water and air into practical fuels and chemicals. These devices take their inspiration from photosynthesis: the process by which plants convert sunlight into food. ̽��ֱ��devices don’t use any outside power: no cables, no batteries – all they need is the power of the sun.

̽��ֱ��team’s newest system takes CO2 directly from the air and converts it into syngas: a key intermediate in the production of many chemicals and pharmaceuticals. ̽��ֱ��researchers say their approach, which does not require any transportation or storage, is much easier to scale up than earlier solar-powered devices.

̽��ֱ��device, a solar-powered flow reactor, uses specialised filters to grab CO2 from the air at night, like how a sponge soaks up water. When the sun comes out, the sunlight heats up the captured CO2, absorbing infrared radiation and a semiconductor powder absorbs the ultraviolet radiation to start a chemical reaction that converts the captured CO2 into solar syngas. A mirror on the reactor concentrates the sunlight, making the process more efficient.

̽��ֱ��researchers are currently working on converting the solar syngas into liquid fuels, which could be used to power cars, planes and more – without adding more CO2 to the atmosphere.

“If we made these devices at scale, they could solve two problems at once: removing CO2 from the atmosphere and creating a clean alternative to fossil fuels,” said Kar. “CO2 is seen as a harmful waste product, but it is also an opportunity.”

̽��ֱ��researchers say that a particularly promising opportunity is in the chemical and pharmaceutical sector, where syngas can be converted into many of the products we rely on every day, without contributing to climate change. They are building a larger scale version of the reactor and hope to begin tests in the spring.

If scaled up, the researchers say their reactor could be used in a decentralised way, so that individuals could theoretically generate their own fuel, which would be useful in remote or off-grid locations.

“Instead of continuing to dig up and burn fossil fuels to produce the products we have come to rely on, we can get all the CO2 we need directly from the air and reuse it,” said Reisner. “We can build a circular, sustainable economy – if we have the political will to do it.”

̽��ֱ��technology is being commercialised with the support of Cambridge Enterprise, the ̽��ֱ��’s commercialisation arm. ̽��ֱ��research was supported in part by UK Research and Innovation (UKRI), the European Research Council, the Royal Academy of Engineering, and the Cambridge Trust. Erwin Reisner is a Fellow of St John’s College, Cambridge.

Reference:
Sayan Kar et al. ‘Direct air capture of CO2 for solar fuels production in flow.’ Nature Energy (2025). DOI: 10.1038/s41560-025-01714-y

For more information on energy-related research in Cambridge, please visit the Energy IRC, which brings together Cambridge’s research knowledge and expertise, in collaboration with global partners, to create solutions for a sustainable and resilient energy landscape for generations to come.

Researchers have developed a reactor that pulls carbon dioxide directly from the air and converts it into sustainable fuel, using sunlight as the power source.

We can build a circular, sustainable economy – if we have the political will to do it

Erwin Reisner

Sayan Kar

Solar-powered flow reactor

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – 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

Sex differences in brain structure present at birth

Anonymous — Tue, 07 Jan 2025 08:00:33 +0000

While male brains tended to be greater in volume than female brains, when adjusted for total brain volume, female infants on average had significantly more grey matter, while male infants on average had significantly more white matter in their brains.

Grey matter is made up of neuron cell bodies and dendrites and is responsible for processing and interpreting information, such as sensation, perception, learning, speech, and cognition. White matter is made up of axons, which are long nerve fibres that connect neurons together from different parts of the brain.

Yumnah Khan, a PhD student at the Autism Research Centre, who led the study, said: “Our study settles an age-old question of whether male and female brains differ at birth. We know there are differences in the brains of older children and adults, but our findings show that they are already present in the earliest days of life.

“Because these sex differences are evident so soon after birth, they might in part reflect biological sex differences during prenatal brain development, which then interact with environmental experiences over time to shape further sex differences in the brain.”

One problem that has plagued past research in this area is sample size. ̽��ֱ��Cambridge team tackled this by analysing data from the Developing Human Connectome Project, where infants receive an MRI brain scan soon after birth. Having over 500 newborn babies in the study means that, statistically, the sample is ideal for detecting sex differences if they are present.

A second problem is whether any observed sex differences could be due to other factors, such as differences in body size. ̽��ֱ��Cambridge team found that, on average, male infants had significantly larger brain volumes than did females, and this was true even after sex differences in birth weight were taken into account.

After taking this difference in total brain volume into account, at a regional level, females on average showed larger volumes in grey matter areas related to memory and emotional regulation, while males on average had larger volumes in grey matter areas involved in sensory processing and motor control.

̽��ֱ��findings of the study, the largest to date to investigate this question, are published in the journal Biology of Sex Differences.

Dr Alex Tsompanidis who supervised the study, said: “This is the largest such study to date, and we took additional factors into account, such as birth weight, to ensure that these differences are specific to the brain and not due to general size differences between the sexes.

“To understand why males and females show differences in their relative grey and white matter volume, we are now studying the conditions of the prenatal environment, using population birth records, as well as in vitro cellular models of the developing brain. This will help us compare the progression of male and female pregnancies and determine if specific biological factors, such as hormones or the placenta, contribute to the differences we see in the brain.”

̽��ֱ��researchers stress that the differences between males and females are average differences.

Dr Carrie Allison, Deputy Director of the Autism Research Centre, said: “ ̽��ֱ��differences we see do not apply to all males or all females, but are only seen when you compare groups of males and females together. There is a lot a variation within, and a lot of overlap between, each group.”

Professor Simon Baron-Cohen, Director of the Autism Research Centre, added: “These differences do not imply the brains of males and females are better or worse. It’s just one example of neurodiversity. This research may be helpful in understanding other kinds of neurodiversity, such as the brain in children who are later diagnosed as autistic, since this is diagnosed more often in males.”

̽��ֱ��research was funded by Cambridge ̽��ֱ�� Development and Research, Trinity College, Cambridge, the Cambridge Trust, and the Simons Foundation Autism Research Initiative.

Reference
Khan, Y T, Tsompanidis, A, Radecki, M A, et al. Sex differences in human brain structure at birth. Biol Sex Differ; 17 Oct 2024; DOI: 10.1186/s13293-024-00657-5

Sex differences in brain structure are present from birth, research from the Autism Research Centre at the ̽��ֱ�� of Cambridge has shown.

We know there are differences in the brains of older children and adults, but our findings show that they are already present in the earliest days of life

Yumnah Khan

Chayene Rafaela

Photograph of a young girl hugging a baby boy

Yes

Licence type:

Public Domain

New open-source platform allows users to evaluate performance of AI-powered chatbots

sc604 — Tue, 04 Jun 2024 10:34:36 +0000

A team of computer scientists, engineers, mathematicians and cognitive scientists, led by the ̽��ֱ�� of Cambridge, developed an open-source evaluation platform called CheckMate, which allows human users to interact with and evaluate the performance of large language models (LLMs).

̽��ֱ��researchers tested CheckMate in an experiment where human participants used three LLMs – InstructGPT, ChatGPT and GPT-4 – as assistants for solving undergraduate-level mathematics problems.

̽��ֱ��team studied how well LLMs can assist participants in solving problems. Despite a generally positive correlation between a chatbot’s correctness and perceived helpfulness, the researchers also found instances where the LLMs were incorrect, but still useful for the participants. However, certain incorrect LLM outputs were thought to be correct by participants. This was most notable in LLMs optimised for chat.

̽��ֱ��researchers suggest models that communicate uncertainty, respond well to user corrections, and can provide a concise rationale for their recommendations, make better assistants. Human users of LLMs should verify their outputs carefully, given their current shortcomings.

̽��ֱ��results, reported in the Proceedings of the National Academy of Sciences (PNAS), could be useful in both informing AI literacy training, and help developers improve LLMs for a wider range of uses.

While LLMs are becoming increasingly powerful, they can also make mistakes and provide incorrect information, which could have negative consequences as these systems become more integrated into our everyday lives.

“LLMs have become wildly popular, and evaluating their performance in a quantitative way is important, but we also need to evaluate how well these systems work with and can support people,” said co-first author Albert Jiang, from Cambridge’s Department of Computer Science and Technology. “We don’t yet have comprehensive ways of evaluating an LLM’s performance when interacting with humans.”

̽��ֱ��standard way to evaluate LLMs relies on static pairs of inputs and outputs, which disregards the interactive nature of chatbots, and how that changes their usefulness in different scenarios. ̽��ֱ��researchers developed CheckMate to help answer these questions, designed for but not limited to applications in mathematics.

“When talking to mathematicians about LLMs, many of them fall into one of two main camps: either they think that LLMs can produce complex mathematical proofs on their own, or that LLMs are incapable of simple arithmetic,” said co-first author Katie Collins from the Department of Engineering. “Of course, the truth is probably somewhere in between, but we wanted to find a way of evaluating which tasks LLMs are suitable for and which they aren’t.”

̽��ֱ��researchers recruited 25 mathematicians, from undergraduate students to senior professors, to interact with three different LLMs (InstructGPT, ChatGPT, and GPT-4) and evaluate their performance using CheckMate. Participants worked through undergraduate-level mathematical theorems with the assistance of an LLM and were asked to rate each individual LLM response for correctness and helpfulness. Participants did not know which LLM they were interacting with.

̽��ֱ��researchers recorded the sorts of questions asked by participants, how participants reacted when they were presented with a fully or partially incorrect answer, whether and how they attempted to correct the LLM, or if they asked for clarification. Participants had varying levels of experience with writing effective prompts for LLMs, and this often affected the quality of responses that the LLMs provided.

An example of an effective prompt is “what is the definition of X” (X being a concept in the problem) as chatbots can be very good at retrieving concepts they know of and explaining it to the user.

“One of the things we found is the surprising fallibility of these models,” said Collins. “Sometimes, these LLMs will be really good at higher-level mathematics, and then they’ll fail at something far simpler. It shows that it’s vital to think carefully about how to use LLMs effectively and appropriately.”

However, like the LLMs, the human participants also made mistakes. ̽��ֱ��researchers asked participants to rate how confident they were in their own ability to solve the problem they were using the LLM for. In cases where the participant was less confident in their own abilities, they were more likely to rate incorrect generations by LLM as correct.

“This kind of gets to a big challenge of evaluating LLMs, because they’re getting so good at generating nice, seemingly correct natural language, that it’s easy to be fooled by their responses,” said Jiang. “It also shows that while human evaluation is useful and important, it’s nuanced, and sometimes it’s wrong. Anyone using an LLM, for any application, should always pay attention to the output and verify it themselves.”

Based on the results from CheckMate, the researchers say that newer generations of LLMs are increasingly able to collaborate helpfully and correctly with human users on undergraduate-level maths problems, as long as the user can assess the correctness of LLM-generated responses. Even if the answers may be memorised and can be found somewhere on the internet, LLMs have the advantage of being flexible in their inputs and outputs over traditional search engines (though should not replace search engines in their current form).

While CheckMate was tested on mathematical problems, the researchers say their platform could be adapted to a wide range of fields. In the future, this type of feedback could be incorporated into the LLMs themselves, although none of the CheckMate feedback from the current study has been fed back into the models.

“These kinds of tools can help the research community to have a better understanding of the strengths and weaknesses of these models,” said Collins. “We wouldn’t use them as tools to solve complex mathematical problems on their own, but they can be useful assistants if the users know how to take advantage of them.”

̽��ֱ��research was supported in part by the Marshall Commission, the Cambridge Trust, Peterhouse, Cambridge, ̽��ֱ��Alan Turing Institute, the European Research Council, and the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation (UKRI).

Reference:
Katherine M Collins, Albert Q Jiang, et al. ‘Evaluating Language Models for Mathematics through Interactions.’ Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2318124121

Researchers have developed a platform for the interactive evaluation of AI-powered chatbots such as ChatGPT.

Anyone using an LLM, for any application, should always pay attention to the output and verify it themselves

Albert Jiang

da-kuk via Getty Images

Chatbot

Yes

Solar-powered device produces clean water and clean fuel at the same time

sc604 — Mon, 13 Nov 2023 16:21:43 +0000

̽��ֱ��device, developed by researchers at the ̽��ֱ�� of Cambridge, could be useful in resource-limited or off-grid environments, since it works with any open water source and does not require any outside power.

It takes its inspiration from photosynthesis, the process by which plants convert sunlight into food. However, unlike earlier versions of the ‘artificial leaf’, which could produce green hydrogen fuel from clean water sources, this new device operates from polluted or seawater sources and can produce clean drinking water at the same time.

Tests of the device showed it was able to produce clean water from highly polluted water, seawater, and even from the River Cam in central Cambridge. ̽��ֱ��results are reported in the journal Nature Water.

“Bringing together solar fuels production and water purification in a single device is tricky,” said Dr Chanon Pornrungroj from Cambridge’s Yusuf Hamied Department of Chemistry, the paper’s co-lead author. “Solar-driven water splitting, where water molecules are broken down into hydrogen and oxygen, need to start with totally pure water because any contaminants can poison the catalyst or cause unwanted chemical side-reactions.”

“In remote or developing regions, where clean water is relatively scarce and the infrastructure necessary for water purification is not readily available, water splitting is extremely difficult,” said co-lead author Ariffin Mohamad Annuar. “A device that could work using contaminated water could solve two problems at once: it could split water to make clean fuel, and it could make clean drinking water.”

Pornrungroj and Mohamad Annuar, who are both members of Professor Erwin Reisner’s research group, came up with a design that did just that. They deposited a photocatalyst on a nanostructured carbon mesh that is a good absorber of both light and heat, generating the water vapour used by the photocatalyst to create hydrogen. ̽��ֱ��porous carbon mesh, treated to repel water, served both to help the photocatalyst float and to keep it away from the water below, so that contaminants do not interfere with its functionality.

In addition, the new device uses more of the Sun’s energy. “ ̽��ֱ��light-driven process for making solar fuels only uses a small portion of the solar spectrum – there’s a whole lot of the spectrum that goes unused,” said Mohamad Annuar.

̽��ֱ��team used a white, UV-absorbing layer on top of the floating device for hydrogen production via water splitting. ̽��ֱ��rest of the light in the solar spectrum is transmitted to the bottom of the device, which vaporises the water.

“This way, we’re making better use of the light – we get the vapour for hydrogen production, and the rest is water vapour,” said Pornrungroj. “This way, we’re truly mimicking a real leaf, since we’ve now been able to incorporate the process of transpiration.”

A device that can make clean fuel and clean water at once using solar power alone could help address the energy and the water crises facing so many parts of the world. For example, the indoor air pollution caused by cooking with ‘dirty’ fuels, such as kerosene, is responsible for more than three million deaths annually, according to the World Health Organization. Cooking with green hydrogen instead could help reduce that number significantly. And 1.8 billion people worldwide still lack safe drinking water at home.

“It’s such a simple design as well: in just a few steps, we can build a device that works well on water from a wide variety of sources,” said Mohamad Annuar.

“It’s so tolerant of pollutants, and the floating design allows the substrate to work in very cloudy or muddy water,” said Pornrungroj. “It’s a highly versatile system.”

“Our device is still a proof of principle, but these are the sorts of solutions we will need if we’re going to develop a truly circular economy and sustainable future,” said Reisner, who led the research. “ ̽��ֱ��climate crisis and issues around pollution and health are closely related, and developing an approach that could help address both would be a game-changer for so many people.”

̽��ֱ��research was supported in part by the European Commission’s Horizon 2020 programme, ̽��ֱ��European Research Council, the Cambridge Trust, the Petronas Education Sponsorship Programme, and the Winton Programme for the Physics of Sustainability. Erwin Reisner is a Fellow of St John’s College. Chanon Pornrungroj is a member of Darwin College, and Ariffin Mohamad Annuar is a member of Clare College.

Reference:
Chanon Pornrungroj, Ariffin Bin Mohamad Annuar et al. ‘Hybrid photothermal-photocatalyst sheets for solar-driven overall water splitting coupled to water purification.’ Nature Water (2023). DOI: 10.1038/s44221-023-00139-9

A floating, solar-powered device that can turn contaminated water or seawater into clean hydrogen fuel and purified water, anywhere in the world, has been developed by researchers.

These are the sorts of solutions we will need to develop a truly circular economy and sustainable future

Erwin Reisner

Chanon Pornrungroj

Device for making solar fuels on the River Cam near the Bridge of Sighs

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� 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

Solar-powered system converts plastic and greenhouse gases into sustainable fuels

sc604 — Mon, 09 Jan 2023 16:00:00 +0000

̽��ֱ��researchers, from the ̽��ֱ�� of Cambridge, developed the system, which can convert two waste streams into two chemical products at the same time – the first time this has been achieved in a solar-powered reactor.

̽��ֱ��reactor converts carbon dioxide (CO2) and plastics into different products that are useful in a range of industries. In tests, CO2 was converted into syngas, a key building block for sustainable liquid fuels, and plastic bottles were converted into glycolic acid, which is widely used in the cosmetics industry. ̽��ֱ��system can easily be tuned to produce different products by changing the type of catalyst used in the reactor.

Converting plastics and greenhouse gases – two of the biggest threats facing the natural world – into useful and valuable products using solar energy is an important step in the transition to a more sustainable, circular economy. ̽��ֱ��results are reported in the journal Nature Synthesis.

“Converting waste into something useful using solar energy is a major goal of our research,” said Professor Erwin Reisner from the Yusuf Hamied Department of Chemistry, the paper’s senior author. “Plastic pollution is a huge problem worldwide, and often, many of the plastics we throw into recycling bins are incinerated or end up in landfill.”

Reisner also leads the Cambridge Circular Plastics Centre (CirPlas), which aims to eliminate plastic waste by combining blue-sky thinking with practical measures.

Other solar-powered ‘recycling’ technologies hold promise for addressing plastic pollution and for reducing the amount of greenhouse gases in the atmosphere, but to date, they have not been combined in a single process.

“A solar-driven technology that could help to address plastic pollution and greenhouse gases at the same time could be a game-changer in the development of a circular economy,” said Subhajit Bhattacharjee, the paper’s co-first author.

“We also need something that’s tuneable, so that you can easily make changes depending on the final product you want,” said co-first author Dr Motiar Rahaman.

̽��ֱ��researchers developed an integrated reactor with two separate compartments: one for plastic, and one for greenhouse gases. ̽��ֱ��reactor uses a light absorber based on perovskite – a promising alternative to silicon for next-generation solar cells.

̽��ֱ��team designed different catalysts, which were integrated into the light absorber. By changing the catalyst, the researchers could then change the end product. Tests of the reactor under normal temperature and pressure conditions showed that the reactor could efficiently convert PET plastic bottles and CO2 into different carbon-based fuels such as CO, syngas or formate, in addition to glycolic acid. ̽��ֱ��Cambridge-developed reactor produced these products at a rate that is also much higher than conventional photocatalytic CO2 reduction processes.

“Generally, CO2 conversion requires a lot of energy, but with our system, basically you just shine a light at it, and it starts converting harmful products into something useful and sustainable,” said Rahaman. “Prior to this system, we didn’t have anything that could make high-value products selectively and efficiently.”

“What’s so special about this system is the versatility and tuneability – we’re making fairly simple carbon-based molecules right now, but in future, we could be able to tune the system to make far more complex products, just by changing the catalyst,” said Bhattacharjee.

Reisner recently received new funding from the European Research Council to help the development of their solar-powered reactor. Over the next five years, they hope to further develop the reactor to produce more complex molecules. ̽��ֱ��researchers say that similar techniques could someday be used to develop an entirely solar-powered recycling plant.

“Developing a circular economy, where we make useful things from waste instead of throwing it into landfill, is vital if we’re going to meaningfully address the climate crisis and protect the natural world,” said Reisner. “And powering these solutions using the Sun means that we’re doing it cleanly and sustainably.”

̽��ֱ��research was supported in part by the European Union, the European Research Council, the Cambridge Trust, Hermann and Marianne Straniak Stiftung, and the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation (UKRI). Erwin Reisner is a Fellow of St John’s College, Cambridge.

Reference:
Subhajit Bhattacharjee, Motiar Rahaman et al. ‘Photoelectrochemical CO2-to-fuel conversion with simultaneous plastic reforming.’ Nature Synthesis (2023). DOI: 10.1038/s44160-022-00196-0

For more information on energy-related research in Cambridge, please visit Energy IRC, which brings together Cambridge’s research knowledge and expertise, in collaboration with global partners, to create solutions for a sustainable and resilient energy landscape for generations to come.

Researchers have developed a system that can transform plastic waste and greenhouse gases into sustainable fuels and other valuable products – using just the energy from the Sun.

A solar-driven technology that could help to address plastic pollution and greenhouse gases at the same time could be a game-changer in the development of a circular economy

Subhajit Bhattacharjee

Reisner Lab

Solar-powered reactor for converting plastic and greenhouse gases into sustainable fuels

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� 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

London Underground polluted with metallic particles small enough to enter human bloodstrem

sc604 — Thu, 15 Dec 2022 15:55:12 +0000

̽��ֱ��London Underground is polluted with ultrafine metallic particles small enough to end up in the human bloodstream, according to ̽��ֱ�� of Cambridge researchers. These particles are so small that they are likely being underestimated in surveys of pollution in the world’s oldest metro system.

Alzheimer’s disease causes cells to overheat and ‘fry like eggs’

sc604 — Tue, 31 May 2022 06:00:00 +0000

̽��ֱ��researchers, from the ̽��ֱ�� of Cambridge, used sensors small and sensitive enough to detect temperature changes inside individual cells, and found that as amyloid-beta misfolds and clumps together, it causes cells to overheat.

In an experiment using human cell lines, the researchers found the heat released by amyloid-beta aggregation could potentially cause other, healthy amyloid-beta to aggregate, causing more and more aggregates to form.

In the same series of experiments, the researchers also showed that amyloid-beta aggregation can be stopped, and the cell temperature lowered, with the addition of a drug compound. ̽��ֱ��experiments also suggest that the compound has potential as a therapeutic for Alzheimer’s disease, although extensive tests and clinical trials would first be required.

̽��ֱ��researchers say their assay could be used as a diagnostic tool for Alzheimer’s disease, or to screen potential drug candidates. ̽��ֱ��results are reported in the Journal of the American Chemical Society.

Alzheimer’s disease affects an estimated 44 million people worldwide, and there are currently no effective diagnostics or treatments. In Alzheimer’s disease, amyloid-beta and another protein called tau build up into tangles and plaques – known collectively as aggregates – causing brain cells to die and the brain to shrink. This results in memory loss, personality changes and difficulty carrying out daily functions.

It is a difficult disease to study, since it develops over decades, and a definitive diagnosis can only be given after examining samples of brain tissue after death. It is still not known what kind of biochemical changes inside a cell lead to amyloid-beta aggregation.

In Professor Gabriele Kaminski Schierle’s research group at Cambridge’s Department of Chemical Engineering and Biotechnology, they have been investigating the possible link between temperature and amyloid-beta aggregation in human cells.

̽��ֱ��field of studying temperature changes inside a cell is known as intracellular thermogenesis. It is a new and challenging field: scientists have developed sensors with which temperature changes can be measured, however, no one has ever tried to use these sensors to study conditions such as Alzheimer’s disease.

“Thermogenesis has been associated with cellular stress, which may promote further aggregation,” said Chyi Wei Chung, the study’s first author. “We believe that when there’s an imbalance in cells, like when the amyloid-beta concentration is slightly too high and it starts to accumulate, cellular temperatures increase.”

“Overheating a cell is like frying an egg – as it heats up, the proteins start to clump together and become non-functional,” said Kaminski Schierle, who led the research.

̽��ֱ��researchers used tiny temperature sensors called fluorescent polymeric thermometers (FTPs) to study the link between aggregation and temperature. They added amyloid-beta to human cell lines to kickstart the aggregation process and used a chemical called FCCP as a control, since it is known to induce an increase in temperature.

They found that as amyloid-beta started to form thread-like aggregates called fibrils, the average temperature of the cells started to rise. ̽��ֱ��increase in cellular temperature was significant compared to cells that did not have any amyloid-beta added.

“As the fibrils start elongating, they release energy in the form of heat,” said Kaminski Schierle. “Amyloid-beta aggregation requires quite a lot of energy to get going, but once the aggregation process starts, it speeds up and releases more heat, allowing more aggregates to form.”

“Once the aggregates have formed, they can exit the cell and be taken up by neighbouring cells, infecting healthy amyloid-beta in those cells,” said Chung. “No one has shown this link between temperature and aggregation in live cells before.”

Using a drug that inhibits amyloid-beta aggregation, the researchers were able to pinpoint the fibrils as the cause of thermogenesis. It had previously been unknown whether protein aggregation or potential damage to mitochondria – the ‘batteries’ that power cells – was responsible for this phenomenon.

̽��ֱ��researchers also found that the rise in cellular temperatures could be mitigated by treating them with an aggregation inhibitor, highlighting its potential as a therapeutic for Alzheimer’s disease.

̽��ֱ��laboratory experiments were complemented by computational modelling describing what might happen to amyloid-beta in an intracellular environment and why it might lead to an increase in intracellular temperatures. ̽��ֱ��researchers hope their work will motivate new studies incorporating different parameters of physiological relevance.

̽��ֱ��research was supported in part by Alzheimer’s Research UK, the Cambridge Trust, Wellcome, and the Medical Research Council, part of UK Research and Innovation (UKRI).

Reference:
Chyi Wei Chung et al. ‘Intracellular Aβ42 aggregation leads to cellular thermogenesis.’ Journal of the American Chemical Society (2022). DOI: 10.1021/jacs.2c03599

Researchers have shown that aggregation of amyloid-beta, one of two key proteins implicated in Alzheimer’s disease, causes cells to overheat and ‘fry like eggs.’

No one has shown this link between temperature and aggregation in live cells before

Chyi Wei Chung

Mammalian cell stained with fluorescence polymeric thermometers and falsely-coloured based on temperature gradients.

Yes

Tiny ‘skyscrapers’ help bacteria convert sunlight into electricity

sc604 — Mon, 07 Mar 2022 16:00:00 +0000

̽��ֱ��researchers, from the ̽��ֱ�� of Cambridge, used 3D printing to create grids of high-rise ‘nano-housing’ where sun-loving bacteria can grow quickly. ̽��ֱ��researchers were then able to extract the bacteria’s waste electrons, left over from photosynthesis, which could be used to power small electronics.

Other research teams have extracted energy from photosynthetic bacteria, but the Cambridge researchers have found that providing them with the right kind of home increases the amount of energy they can extract by over an order of magnitude. ̽��ֱ��approach is competitive against traditional methods of renewable bioenergy generation and has already reached solar conversion efficiencies that can outcompete many current methods of biofuel generation.

Their results, reported in the journal Nature Materials, open new avenues in bioenergy generation and suggest that ‘biohybrid’ sources of solar energy could be an important component in the zero-carbon energy mix.

Current renewable technologies, such as silicon-based solar cells and biofuels, are far superior to fossil fuels in terms of carbon emissions, but they also have limitations, such as a reliance on mining, challenges in recycling, and a reliance on farming and land use, which results in biodiversity loss.

“Our approach is a step towards making even more sustainable renewable energy devices for the future,” said Dr Jenny Zhang from the Yusuf Hamied Department of Chemistry, who led the research.

Zhang and her colleagues from the Department of Biochemistry and the Department of Materials Science and Metallurgy are working to rethink bioenergy into something that is sustainable and scalable.

Photosynthetic bacteria, or cyanobacteria, are the most abundant life from on Earth. For several years, researchers have been attempting to ‘re-wire’ the photosynthesis mechanisms of cyanobacteria in order to extract energy from them.

“There’s been a bottleneck in terms of how much energy you can actually extract from photosynthetic systems, but no one understood where the bottleneck was,” said Zhang. “Most scientists assumed that the bottleneck was on the biological side, in the bacteria, but we’ve found that a substantial bottleneck is actually on the material side.”

In order to grow, cyanobacteria need lots of sunlight – like the surface of a lake in summertime. And in order to extract the energy they produce through photosynthesis, the bacteria need to be attached to electrodes.

̽��ֱ��Cambridge team 3D-printed custom electrodes out of metal oxide nanoparticles that are tailored to work with the cyanobacteria as they perform photosynthesis. ̽��ֱ��electrodes were printed as highly branched, densely packed pillar structures, like a tiny city.

Zhang’s team developed a printing technique that allows control over multiple length scales, making the structures highly customisable, which could benefit a wide range of fields.

“ ̽��ֱ��electrodes have excellent light-handling properties, like a high-rise apartment with lots of windows,” said Zhang. “Cyanobacteria need something they can attach to and form a community with their neighbours. Our electrodes allow for a balance between lots of surface area and lots of light – like a glass skyscraper.”

Once the self-assembling cyanobacteria were in their new ‘wired’ home, the researchers found that they were more efficient than other current bioenergy technologies, such as biofuels. ̽��ֱ��technique increased the amount of energy extracted by over an order of magnitude over other methods for producing bioenergy from photosynthesis.

“I was surprised we were able to achieve the numbers we did – similar numbers have been predicted for many years, but this is the first time that these numbers have been shown experimentally,” said Zhang. “Cyanobacteria are versatile chemical factories. Our approach allows us to tap into their energy conversion pathway at an early point, which helps us understand how they carry out energy conversion so we can use their natural pathways for renewable fuel or chemical generation.”

̽��ֱ��research was supported in part by the Biotechnology and Biological Sciences Research Council, the Cambridge Trust, the Isaac Newton Trust and the European Research Council. Jenny Zhang is BBSRC David Phillips Fellow in the Department of Chemistry, and a Fellow of Corpus Christi College, Cambridge.

Reference:
Xiaolong Chen et al. ‘3D-printed hierarchical pillar array electrodes for high performance semi-artificial photosynthesis.’ Nature Materials (2022). DOI: 10.1038/s41563-022-01205-5

Researchers have made tiny ‘skyscrapers’ for communities of bacteria, helping them to generate electricity from just sunlight and water.

Our approach is a step towards making even more sustainable renewable energy devices for the future

Jenny Zhang

Gabriella Bocchetti

3D-printed custom electrodes

Yes