Tag Archives: Gang Chen

A world without blood type constraints and the first human transplant of a modified kidney

Leave a reply

In fact, it should be “imagine a world without blood type constraints.” That’s what you’ll find on The Avivo Biomedical homepage, a University of British Columbia (UBC) spin-off company, which is associated with at least one of the researchers involved in this rather extraordinary work. From an October 3, 2025 UBC news release, also received via email *ETA October 3, 2025 1640 PT: and available on EurekAlert*,

The first successful human transplant of a kidney converted from blood type A to universal type O used special enzymes developed at the University of British Columbia to help prevent a mismatch and rejection of the organ.

Published today [October 3, 2025] in Nature Biomedical Engineering, the achievement marks a major step toward helping thousands of patients get kidney transplants sooner.

In a first-in-human experiment, the enzyme-converted kidney was transplanted into a brain-dead recipient with consent from the family, allowing researchers to observe the immune response without risking a life.

For two days, the kidney functioned without signs of hyperacute rejection, the rapid immune reaction that can destroy an incompatible organ within minutes. By the third day, some blood-type markers reappeared, triggering a mild reaction, but the damage was far less severe than in a typical mismatch, and researchers saw signs that the body was beginning to tolerate the organ.

“This is the first time we’ve seen this play out in a human model,” said Dr. Stephen Withers, UBC professor emeritus of chemistry who co-led the enzyme development. “It gives us invaluable insight into how to improve long-term outcomes.”

The breakthrough is the result of more than a decade of work. In the early 2010s, Dr. Withers and colleague Dr. Jayachandran Kizhakkedathu, a UBC professor in the department of pathology and laboratory medicine and the Centre for Blood Research, were focused on making universal donor blood by stripping away the sugars that define blood types.

Those same sugars, or antigens, coat organ blood vessels. If a recipient’s immune system detects the wrong antigen, it attacks. Type-O patients—more than half of kidney waitlists—can only receive type-O organs, yet type-O kidneys are often given to others because they’re universally compatible. As a result, type-O patients typically wait two to four years longer, and many die waiting.

Traditional methods for overcoming blood-type incompatibility in transplants require days of intensive treatment to strip antibodies and suppress a recipient’s immune system—and require organs from living donors. This new approach changes the organ rather than the patient, meaning transplants could be performed faster, with fewer complications, and for the first time could unlock the use of blood-type mismatched organs from deceased donors—when every hour can determine whether a patient lives or dies.

The key to this approach is the 2019 discovery by the UBC team of two highly efficient enzymes that remove the sugar that defines type-A blood, effectively converting it to type O. “These enzymes are highly active, highly selective, and work at very low concentrations,” said Dr. Kizhakkedathu. “That made the whole concept feasible.”

The next challenge was applying this to whole organs, achieved in 2022 when a Toronto team showed lungs could be converted. After successful tests on blood, then lungs and kidneys (with the University of Cambridge) outside the body, the question remained: Could an enzyme-converted organ survive inside a human immune system?

The answer came in late 2023 on an overseas trip for Dr. Kizhakkedathu. “Our collaborators showed me their data where, using our enzymes, they had converted a human kidney and transplanted it into a brain-dead recipient. It was working beautifully.” He stayed up late to call Dr. Withers first thing in the B.C. morning. “I was so thrilled. It was a dream moment.”

Blood-type antigens act like nametags on cells, and the UBC enzymes act as molecular scissors, snipping off the ‘nametag’ that marks type A and revealing type O beneath. “It’s like removing the red paint from a car and uncovering the neutral primer,” said Dr. Withers. “Once that’s done, the immune system no longer sees the organ as foreign.”

Regulatory approval for clinical trials is the next hurdle, and the partner UBC spin-off company Avivo Biomedical will lead development of these enzymes for transplant application and to enable the creation of universal donor blood on demand for transfusion medicine.

The potential is enormous. “This is what it looks like when years of basic science finally connect to patient care,” said Dr. Withers. “Seeing our discoveries edge closer to real-world impact is what keeps us pushing forward.”

Before getting to the citation and link for the paper, Rachel Fieldhouse’s October 3, 2025 article for Nature offers a little more detail, Note: This article is behind a paywall,

Scientists have converted the blood type of a donor kidney and transplanted the organ into a person. The procedure — the first of its kind — could improve access to donor organs, specialists say, because the blood type of the donor would no longer matter.

…

Researchers from Canada and China used an enzyme to remove type-A antigens from a donor kidney1. The enzyme converts type-A blood into type-O, says study author Stephen Withers, a chemist at the University of British Columbia in Vancouver, Canada. The type-O kidney was then transplanted into a 68-year-old brain-dead man in Chongqing, China. The organ remained healthy for two days before showing signs of rejection. It produced urine for six days. The results are published in Nature Biomedical Engineering today [October 3, 2025].

…

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

Enzyme-converted O kidneys allow ABO-incompatible transplantation without hyperacute rejection in a human decedent model by Jun Zeng, Ming Ma, Ze Tao, Zhengsheng Rao, Chaomeng Wu, Saifu Yin, Xiaojuan Jiang, Guo Chen, Zhiling Wang, Dan Huang, Mengli Zhu, Ling Liu, Wenqian Huo, Hao Yang, Hui Guo, Gang Chen, Feng Li, Chengyu Zheng, Dajiu Huang, Peter Rahfeld, Jayachandran N. Kizhakkedathu, Stephen G. Withers, Xiaofeng Lu, Keqin Zhang, Tao Lin & Turun Song. Nature Biomedical Engineering (2025) DOI: https://doi.org/10.1038/s41551-025-01513-6 Published0: 3 October 2025

This paper is behind a paywall.

Bravo to all of the researchers involved in this multi-year and multi-continent effort.

Follow up to the Charles M. Lieber affair and US government efforts to prosecute nanotech scientists

Leave a reply

Rebecca Trager in a March 5, 2021 news article for Chemistry World highlights support for Charles M. Lieber (Harvard professor and chair of the chemistry department) from his colleagues (Note: Links have been removed),

More than a year after the chair of Harvard University’s chemistry department was arrested for allegedly hiding his receipt of millions of dollars in research funding from China from his university and the US government, dozens of prominent researchers – including many Nobel Prize winners – are coming to Charles Lieber’s defence. They are calling the US Department of Justice (DOJ) case against him ‘unjust’ and urging the agency to drop it.

Following his January 2020 arrest, Lieber was placed on ‘indefinite’ paid administrative leave. The nanoscience pioneer was indicted in June [2020] on charges of making false statements to federal authorities regarding his participation in China’s Thousand Talents plan – the country’s programme to attract, recruit and cultivate high-level scientific talent from abroad. Lieber faces up to five years in prison and a fine of $250,000 (£179,000) if convicted.

A 1 March [2021] open letter, drafted and coordinated by Harvard chemist Stuart Schreiber, co-founder of the Broad Institute, and professor emeritus Elias Corey, winner of the 1990 chemistry Nobel prize, says Lieber became the target of a ‘tragically misguided government campaign’. The letter refers to Lieber as ‘one of the great scientist of his generation’ and warns such government actions are discouraging US scientists from collaborating with peers in other countries, particularly China. The open letter also notes that Lieber is fighting to salvage his reputation while suffering from incurable lymphoma.

…

Ferguson goes on to contrast Lieber’s treatment by Harvard to another embattled colleague’s treatment by his home institution (Note: Links have been removed),

Harvard’s treatment of Lieber stands in contrast to how the Massachusetts Institute of Technology (MIT) handled the more recent case of nanotechnologist Gang Chen, who was arrested in January [2021] for failing to report his ties to the Chinese government. MIT agreed to cover his legal fees, and more than 100 faculty members signed a letter to their university’s president that picked apart the DOJ’s allegations against Chen.

…

I have more details about the case against Lieber (as it was presented at the time) in a January 28, 2020 posting.

As for Professor Chen, I found this MIT statement dated January 14, 2021 (the date of his arrest) and this January 14, 2021 statement from The United States District Attorney’s Office District of Massachusetts.

Getting back to incandescent light (recycling the military way)

Leave a reply

MIT (Massachusetts Institute of Technology) issued two news releases about this research into reclaiming incandescent light or as they call it “recycling light.” First off, there’s the Jan. 11, 2016 MIT Institute of Soldier Nanotechnologies news release by Paola Rebusco on EurekAlert,

Humanity started recycling relatively early in its evolution: there are proofs that trash recycling was taking place as early as in the 500 BC. What about light recycling? Consider light bulbs: more than one hundred and thirty years ago Thomas Edison patented the first commercially viable incandescent light bulb, so that “none but the extravagant” would ever “burn tallow candles”, paving the way for more than a century of incandescent lighting. In fact, emergence of electric lighting was the main motivating factor for deployment of electricity into every home in the world. The incandescent bulb is an example of a high temperature thermal emitter. It is very useful, but only a small fraction of the emitted light (and therefore energy) is used: most of the light is emitted in the infrared, invisible to the human eye, and in this context wasted.

Now, in a study published in Nature Nanotechnology on January 11th 2016 (online), a team of MIT researchers describes another way to recycle light emitted at unwanted infrared wavelengths while optimizing the emission at useful visible wavelengths. …

“For a thermal emitter at moderate temperatures one usually nano-patterns its surface to alter the emission,” says Ilic [postdoc Ognjen Ilic], the lead author of the study. “At high temperatures” – a light bulb filament reaches 3000K! – “such nanostructures deteriorate and it is impossible to alter the emission spectrum by having a nanostructure directly on the surface of the emitter.” The team solved the problem by surrounding the hot object with special nanophotonic structures that spectrally filter the emitted light, meaning that they let the light reflect or pass through based on its color (i.e. its wavelength). Because the filters are not in direct physical contact with the emitter, temperatures can be very high.

To showcase this idea, the team picked one of the highest temperature thermal emitters available – an incandescent light bulb. The authors designed nanofilters to recycle the infrared light, while allowing the visible light to go through. “The key advance was to design a photonic structure that transmits visible light and reflects infrared light for a very wide range of angles,” explains Ilic. “Conventional photonic filters usually operate for a single incidence angle. The challenge for us was to extend the desired optical properties across all directions,” a feat the authors achieved using special numerical optimization techniques.

However, for this scheme to work, the authors had to redesign the incandescent filament from scratch. “In a regular light bulb, the filament is a long and curly piece of tungsten wire. Here, the filament is laser-machined out of a flat sheet of tungsten: it is completely planar,” says Bermel [professor Peter Bermel now at Purdue University]. A planar filament has a large area, and is therefore very efficient in re-absorbing the light that was reflected by the filter. In describing how the new device differs from previously suggested concepts, Soljačić [professor Marin Soljačić], the project lead, emphasizes that “it is the combination of the exceptional properties of the filter and the shape of the filament that enabled substantial recycling of unwanted radiated light.”

In the new-concept light bulb prototype built by the authors, the efficiency approaches some fluorescent and LED bulbs. Nonetheless, the theoretical model predicts plenty of room for improvement. “This experimental device is a proof-of-concept, at the low end of performance that could be ultimately achieved by this approach,” argues Celanovic [principal research scientist Ivan Celanovic]. There are other advantages of this approach: “An important feature is that our demonstrated device achieves near-ideal rendering of colors,” notes Ilic, referring to the requirement of light sources to faithfully reproduce surrounding colors. That is precisely the reason why incandescent lights remained dominant for so long: their warm light has remained preferable to drab fluorescent lighting for decades.

Some practical questions need to be addressed before this technology can be widely adopted. “We will work closely with our mechanical engineering colleagues at MIT to try to tackle the issues of thermal stability and long-lifetime,” says Soljačić. The authors are particularly excited about the potential for producing these devices cheaply. “The materials we need are abundant and inexpensive,” Joannopoulos [professor John Joannopoulos] notes, “and the filters themselves–consisting of stacks of commonly deposited materials–are amenable to large-scale deposition.”

Chen [professor Gang Chen] comments further: “The lighting potential of this technology is exciting, but the same approach could also be used to improve the performance of energy conversion schemes such as thermo-photovoltaics.” In a thermo-photovoltaic device, external heat causes the material to glow, emitting light that is converted into an electric current by an absorbing photovoltaic element.

The last point captures the main motivation behind the work. “Light radiated from a hot object can be quite useful, whether that object is an incandescent filament or the Sun,” Ilic says. At its core, this work is about recycling thermal light for a specific application; “a 3000-degree filament is one of the hottest and the most challenging sources to work with,” Ilic continues. “It’s also what makes it a crucial test of our approach.”

There are a few more details in the 2nd Jan. 11, 2016 MIT news release on EurekAlert,

Light recycling

The key is to create a two-stage process, the researchers report. The first stage involves a conventional heated metal filament, with all its attendant losses. But instead of allowing the waste heat to dissipate in the form of infrared radiation, secondary structures surrounding the filament capture this radiation and reflect it back to the filament to be re-absorbed and re-emitted as visible light. These structures, a form of photonic crystal, are made of Earth-abundant elements and can be made using conventional material-deposition technology.

That second step makes a dramatic difference in how efficiently the system converts light into electricity. The efficiency of conventional incandescent lights is between 2 and 3 percent, while that of fluorescents (including CFLs) is currently between 7 and 13 percent, and that of LEDs between 5 and 13 percent. In contrast, the new two-stage incandescents could reach efficiencies as high as 40 percent, the team says.

The first proof-of-concept units made by the team do not yet reach that level, achieving about 6.6 percent efficiency. But even that preliminary result matches the efficiency of some of today’s CFLs and LEDs, they point out. And it is already a threefold improvement over the efficiency of today’s incandescents.

The team refers to their approach as “light recycling,” says Ilic, since their material takes in the unwanted, useless wavelengths of energy and converts them into the visible light wavelengths that are desired. “It recycles the energy that would otherwise be wasted,” says Soljačić.

Bulbs and beyond

One key to their success was designing a photonic crystal that works for a very wide range of wavelengths and angles. The photonic crystal itself is made as a stack of thin layers, deposited on a substrate. “When you put together layers, with the right thicknesses and sequence,” Ilic explains, you can get very efficient tuning of how the material interacts with light. In their system, the desired visible wavelengths pass right through the material and on out of the bulb, but the infrared wavelengths get reflected as if from a mirror. They then travel back to the filament, adding more heat that then gets converted to more light. Since only the visible ever gets out, the heat just keeps bouncing back in toward the filament until it finally ends up as visible light.

I appreciate both MIT news release writers for “Thomas Edison patented the first commercially viable incandescent light bulb” (Rebusco) and the unidentified writer of the 2nd MIT news release for this, from the news release, “Incandescent bulbs, commercially developed by Thomas Edison (and still used by cartoonists as the symbol of inventive insight) … .” Edison did not invent the light bulb. BTW, the emphases are mine.

For interested parties, here’s a link to and a citation for the paper,

Tailoring high-temperature radiation and the resurrection of the incandescent source by Ognjen Ilic, Peter Bermel, Gang Chen, John D. Joannopoulos, Ivan Celanovic, & Marin Soljačić. Nature Nanotechnology  (2016) doi:10.1038/nnano.2015.309 Published online 11 January 2016

This paper is behind a paywall.

Steampower via nanotechnology

Leave a reply

It seems that researchers at MIT (Massachusetts Institute of Technology (US) have been inspired by steam punk, of a sort. From a July 21, 2014 news item on Nanowerk,

A new material structure developed at MIT generates steam by soaking up the sun.

The structure — a layer of graphite flakes and an underlying carbon foam — is a porous, insulating material structure that floats on water. When sunlight hits the structure’s surface, it creates a hotspot in the graphite, drawing water up through the material’s pores, where it evaporates as steam. The brighter the light, the more steam is generated.

The new material is able to convert 85 percent of incoming solar energy into steam — a significant improvement over recent approaches to solar-powered steam generation. What’s more, the setup loses very little heat in the process, and can produce steam at relatively low solar intensity. This would mean that, if scaled up, the setup would likely not require complex, costly systems to highly concentrate sunlight.

A July 21, 2014 MIT news release, which originated the news item, details the research,

Hadi Ghasemi, a postdoc in MIT’s Department of Mechanical Engineering, says the spongelike structure can be made from relatively inexpensive materials — a particular advantage for a variety of compact, steam-powered applications.

“Steam is important for desalination, hygiene systems, and sterilization,” says Ghasemi, who led the development of the structure. “Especially in remote areas where the sun is the only source of energy, if you can generate steam with solar energy, it would be very useful.”

…

Today, solar-powered steam generation involves vast fields of mirrors or lenses that concentrate incoming sunlight, heating large volumes of liquid to high enough temperatures to produce steam. However, these complex systems can experience significant heat loss, leading to inefficient steam generation.

Recently, scientists have explored ways to improve the efficiency of solar-thermal harvesting by developing new solar receivers and by working with nanofluids. The latter approach involves mixing water with nanoparticles that heat up quickly when exposed to sunlight, vaporizing the surrounding water molecules as steam. But initiating this reaction requires very intense solar energy — about 1,000 times that of an average sunny day.

By contrast, the MIT approach generates steam at a solar intensity about 10 times that of a sunny day — the lowest optical concentration reported thus far. The implication, the researchers say, is that steam-generating applications can function with lower sunlight concentration and less-expensive tracking systems.

“This is a huge advantage in cost-reduction,” Ghasemi says. “That’s exciting for us because we’ve come up with a new approach to solar steam generation.”

…

The approach itself is relatively simple: Since steam is generated at the surface of a liquid, Ghasemi looked for a material that could both efficiently absorb sunlight and generate steam at a liquid’s surface.

After trials with multiple materials, he settled on a thin, double-layered, disc-shaped structure. Its top layer is made from graphite that the researchers exfoliated by placing the material in a microwave. The effect, Chen says, is “just like popcorn”: The graphite bubbles up, forming a nest of flakes. The result is a highly porous material that can better absorb and retain solar energy.

The structure’s bottom layer is a carbon foam that contains pockets of air to keep the foam afloat and act as an insulator, preventing heat from escaping to the underlying liquid. The foam also contains very small pores that allow water to creep up through the structure via capillary action.

As sunlight hits the structure, it creates a hotspot in the graphite layer, generating a pressure gradient that draws water up through the carbon foam. As water seeps into the graphite layer, the heat concentrated in the graphite turns the water into steam. The structure works much like a sponge that, when placed in water on a hot, sunny day, can continuously absorb and evaporate liquid.

The researchers tested the structure by placing it in a chamber of water and exposing it to a solar simulator — a light source that simulates various intensities of solar radiation. They found they were able to convert 85 percent of solar energy into steam at a solar intensity 10 times that of a typical sunny day.

Ghasemi says the structure may be designed to be even more efficient, depending on the type of materials used.

“There can be different combinations of materials that can be used in these two layers that can lead to higher efficiencies at lower concentrations,” Ghasemi says. “There is still a lot of research that can be done on implementing this in larger systems.”

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

Solar steam generation by heat localization by Hadi Ghasemi, George Ni, Amy Marie Marconnet, James Loomis, Selcuk Yerci, Nenad Miljkovic, & Gang Chen. Nature Communications 5, Article number: 4449 doi:10.1038/ncomms5449 Published 21 July 2014

This paper is behind a paywall but a free preview is available via ReadCube Access.