Tag Archives: Rice University

First CRISPR gene-edited babies? Ethics and the science story

Scientists, He Jiankui and Michael Deem, may have created the first human babies born after being subjected to CRISPR (clustered regularly interspaced short palindromic repeats) gene editing.  At this point, no one is entirely certain that these babies  as described actually exist since the information was made public in a rather unusual (for scientists) fashion.

The news broke on Sunday, November 25, 2018 through a number of media outlets none of which included journals associated with gene editing or high impact journals such as Cell, Nature, or Science.The news broke in MIT Technology Review and in Associated Press. Plus, this all happened just before the Second International Summit on Human Genome Editing (Nov. 27 – 29, 2018) in Hong Kong. He Jiankui was scheduled to speak today, Nov. 27, 2018.

Predictably, this news has caused quite a tizzy.

Breaking news

Antonio Regalado broke the news in a November 25, 2018  article for MIT [Massachusetts Institute of Technology] Technology Review (Note: Links have been removed),

According to Chinese medical documents posted online this month (here and here), a team at the Southern University of Science and Technology, in Shenzhen, has been recruiting couples in an effort to create the first gene-edited babies. They planned to eliminate a gene called CCR5 in hopes of rendering the offspring resistant to HIV, smallpox, and cholera.

The clinical trial documents describe a study in which CRISPR is employed to modify human embryos before they are transferred into women’s uteruses.

The scientist behind the effort, He Jiankui, did not reply to a list of questions about whether the undertaking had produced a live birth. Reached by telephone, he declined to comment.

However, data submitted as part of the trial listing shows that genetic tests have been carried out on fetuses as late as 24 weeks, or six months. It’s not known if those pregnancies were terminated, carried to term, or are ongoing.

Apparently He changed his mind because Marilynn Marchione in a November 26, 2018 article for the Associated Press confirms the news,

A Chinese researcher claims that he helped make the world’s first genetically edited babies — twin girls born this month whose DNA he said he altered with a powerful new tool capable of rewriting the very blueprint of life.

If true, it would be a profound leap of science and ethics.

A U.S. scientist [Dr. Michael Deem] said he took part in the work in China, but this kind of gene editing is banned in the United States because the DNA changes can pass to future generations and it risks harming other genes.

Many mainstream scientists think it’s too unsafe to try, and some denounced the Chinese report as human experimentation.

There is no independent confirmation of He’s claim, and it has not been published in a journal, where it would be vetted by other experts. He revealed it Monday [November 26, 2018] in Hong Kong to one of the organizers of an international conference on gene editing that is set to begin Tuesday [November 27, 2018], and earlier in exclusive interviews with The Associated Press.

“I feel a strong responsibility that it’s not just to make a first, but also make it an example,” He told the AP. “Society will decide what to do next” in terms of allowing or forbidding such science.

Some scientists were astounded to hear of the claim and strongly condemned it.

It’s “unconscionable … an experiment on human beings that is not morally or ethically defensible,” said Dr. Kiran Musunuru, a University of Pennsylvania gene editing expert and editor of a genetics journal.

“This is far too premature,” said Dr. Eric Topol, who heads the Scripps Research Translational Institute in California. “We’re dealing with the operating instructions of a human being. It’s a big deal.”

However, one famed geneticist, Harvard University’s George Church, defended attempting gene editing for HIV, which he called “a major and growing public health threat.”

“I think this is justifiable,” Church said of that goal.

h/t Cale Guthrie Weissman’s Nov. 26, 2018 article for Fast Company.

Diving into more detail

Ed Yong in a November 26, 2018 article for The Atlantic provides more details about the claims (Note: Links have been removed),

… “Two beautiful little Chinese girls, Lulu and Nana, came crying into the world as healthy as any other babies a few weeks ago,” He said in the first of five videos, posted yesterday {Nov. 25, 2018] to YouTube [link provided at the end of this section of the post]. “The girls are home now with their mom, Grace, and dad, Mark.” The claim has yet to be formally verified, but if true, it represents a landmark in the continuing ethical and scientific debate around gene editing.

Late last year, He reportedly enrolled seven couples in a clinical trial, and used their eggs and sperm to create embryos through in vitro fertilization. His team then used CRISPR to deactivate a single gene called CCR5 in the embryos, six of which they then implanted into mothers. CCR5 is a protein that the HIV virus uses to gain entry into human cells; by deactivating it, the team could theoretically reduce the risk of infection. Indeed, the fathers in all eight couples were HIV-positive.

Whether the experiment was successful or not, it’s intensely controversial. Scientists have already begun using CRISPR and other gene-editing technologies to alter human cells, in attempts to treat cancers, genetic disorders, and more. But in these cases, the affected cells stay within a person’s body. Editing an embryo [it’s often called, germline editing] is very different: It changes every cell in the body of the resulting person, including the sperm or eggs that would pass those changes to future generations. Such work is banned in many European countries, and prohibited in the United States. “I understand my work will be controversial, but I believe families need this technology and I’m willing to take the criticism for them,” He said.

“Was this a reasonable thing to do? I would say emphatically no,” says Paula Cannon of the University of Southern California. She and others have worked on gene editing, and particularly on trials that knock out CCR5 as a way to treat HIV. But those were attempts to treat people who were definitively sick and had run out of other options. That wasn’t the case with Nana and Lulu.

“The idea that being born HIV-susceptible, which is what the vast majority of humans are, is somehow a disease state that requires the extraordinary intervention of gene editing blows my mind,” says Cannon. “I feel like he’s appropriating this potentially valuable therapy as a shortcut to doing something in the sphere of gene editing. He’s either very naive or very cynical.”

“I want someone to make sure that it has happened,” says Hank Greely, an ethicist at Stanford University. If it hasn’t, that “would be a pretty bald-faced fraud,” but such deceptions have happened in the past. “If it is true, I’m disappointed. It’s reckless on safety grounds, and imprudent and stupid on social grounds.” He notes that a landmark summit in 2015 (which included Chinese researchers) and a subsequent major report from the National Academies of Science, Engineering, and Medicine both argued that “public participation should precede any heritable germ-line editing.” That is: Society needs to work out how it feels about making gene-edited babies before any babies are edited. Absent that consensus, He’s work is “waving a red flag in front of a bull,” says Greely. “It provokes not just the regular bio-Luddites, but also reasonable people who just wanted to talk it out.”

Societally, the creation of CRISPR-edited babies is a binary moment—a Rubicon that has been crossed. But scientifically, the devil is in the details, and most of those are still unknown.

CRISPR is still inefficient. [emphasis mine] The Chinese teams who first used it to edit human embryos only did so successfully in a small proportion of cases, and even then, they found worrying levels of “off-target mutations,” where they had erroneously cut parts of the genome outside their targeted gene. He, in his video, claimed that his team had thoroughly sequenced Nana and Lulu’s genomes and found no changes in genes other than CCR5.

That claim is impossible to verify in the absence of a peer-reviewed paper, or even published data of any kind. “The paper is where we see whether the CCR5 gene was properly edited, what effect it had at the cellular level, and whether [there were] any off-target effects,” said Eric Topol of the Scripps Research Institute. “It’s not just ‘it worked’ as a binary declaration.”

In the video, He said that using CRISPR for human enhancement, such as enhancing IQ or selecting eye color, “should be banned.” Speaking about Nana and Lulu’s parents, he said that they “don’t want a designer baby, just a child who won’t suffer from a disease that medicine can now prevent.”

But his rationale is questionable. Huang [Junjiu Huang of Sun Yat-sen University ], the first Chinese researcher to use CRISPR on human embryos, targeted the faulty gene behind an inherited disease called beta thalassemia. Mitalipov, likewise, tried to edit a gene called MYBPC3, whose faulty versions cause another inherited disease called hypertrophic cardiomyopathy (HCM). Such uses are still controversial, but they rank among the more acceptable applications for embryonic gene editing as ways of treating inherited disorders for which treatments are either difficult or nonexistent.

In contrast, He’s team disableda normal gene in an attempt to reduce the risk of a disease that neither child had—and one that can be controlled. There are already ways of preventing fathers from passing HIV to their children. There are antiviral drugs that prevent infections. There’s safe-sex education. “This is not a plague for which we have no tools,” says Cannon.

As Marilynn Marchione of the AP reports, early tests suggest that He’s editing was incomplete [emphasis mine], and at least one of the twins is a mosaic, where some cells have silenced copies of CCR5 and others do not. If that’s true, it’s unlikely that they would be significantly protected from HIV. And in any case, deactivating CCR5 doesn’t confer complete immunity, because some HIV strains can still enter cells via a different protein called CXCR4.

Nana and Lulu might have other vulnerabilities. …

It is also unclear if the participants in He’s trial were fully aware of what they were signing up for. [emphasis mine] The team’s informed-consent document describes their work as an “AIDS vaccine development project,” and while it describes CRISPR gene editing, it does so in heavily technical language. It doesn’t mention any of the risks of disabling CCR5, and while it does note the possibility of off-target effects, it also says that the “project team is not responsible for the risk.”

He owns two genetics companies, and his collaborator, Michael Deem of Rice University,  [emphasis mine] holds a small stake in, and sits on the advisory board of, both of them. The AP’s Marchione reports, “Both men are physics experts with no experience running human clinical trials.” [emphasis mine]

Yong’s article is well worth reading in its entirety. As for YouTube, here’s The He Lab’s webpage with relevant videos.

Reactions

Gina Kolata, Sui-Lee Wee, and Pam Belluck writing in a Nov. 26, 2018 article for the New York Times chronicle some of the response to He’s announcement,

It is highly unusual for a scientist to announce a groundbreaking development without at least providing data that academic peers can review. Dr. He said he had gotten permission to do the work from the ethics board of the hospital Shenzhen Harmonicare, but the hospital, in interviews with Chinese media, denied being involved. Cheng Zhen, the general manager of Shenzhen Harmonicare, has asked the police to investigate what they suspect are “fraudulent ethical review materials,” according to the Beijing News.

The university that Dr. He is attached to, the Southern University of Science and Technology, said Dr. He has been on no-pay leave since February and that the school of biology believed that his project “is a serious violation of academic ethics and academic norms,” according to the state-run Beijing News.

In a statement late on Monday, China’s national health commission said it has asked the health commission in southern Guangdong province to investigate Mr. He’s claims.

“I think that’s completely insane,” said Shoukhrat Mitalipov, director of the Center for Embryonic Cell and Gene Therapy at Oregon Health and Science University. Dr. Mitalipov broke new ground last year by using gene editing to successfully remove a dangerous mutation from human embryos in a laboratory dish. [I wrote a three-part series about CRISPR, which included what was then the latest US news, Mitalipov’s announcement, along with a roundup of previous work in China. Links are at the end of this section.’

Dr. Mitalipov said that unlike his own work, which focuses on editing out mutations that cause serious diseases that cannot be prevented any other way, Dr. He did not do anything medically necessary. There are other ways to prevent H.I.V. infection in newborns.

Just three months ago, at a conference in late August on genome engineering at Cold Spring Harbor Laboratory in New York, Dr. He presented work on editing the CCR₅ gene in the embryos of nine couples.

At the conference, whose organizers included Jennifer Doudna, one of the inventors of Crispr technology, Dr. He gave a careful talk about something that fellow attendees considered squarely within the realm of ethically approved research. But he did not mention that some of those embryos had been implanted in a woman and could result in genetically engineered babies.

“What we now know is that as he was talking, there was a woman in China carrying twins,” said Fyodor Urnov, deputy director of the Altius Institute for Biomedical Sciences and a visiting researcher at the Innovative Genomics Institute at the University of California. “He had the opportunity to say ‘Oh and by the way, I’m just going to come out and say it, people, there’s a woman carrying twins.’”

“I would never play poker against Dr. He,” Dr. Urnov quipped.

Richard Hynes, a cancer researcher at the Massachusetts Institute of Technology, who co-led an advisory group on human gene editing for the National Academy of Sciences and the National Academy of Medicine, said that group and a similar organization in Britain had determined that if human genes were to be edited, the procedure should only be done to address “serious unmet needs in medical treatment, it had to be well monitored, it had to be well followed up, full consent has to be in place.”

It is not clear why altering genes to make people resistant to H.I.V. is “a serious unmet need.” Men with H.I.V. do not infect embryos. …

Dr. He got his Ph.D., from Rice University, in physics and his postdoctoral training, at Stanford, was with Stephen Quake, a professor of bioengineering and applied physics who works on sequencing DNA, not editing it.

Experts said that using Crispr would actually be quite easy for someone like Dr. He.

After coming to Shenzhen in 2012, Dr. He, at age 28, established a DNA sequencing company, Direct Genomics, and listed Dr. Quake on its advisory board. But, in a telephone interview on Monday, Dr. Quake said he was never associated with the company.

Deem, the US scientist who worked in China with He is currently being investigated (from a Nov. 26, 2018 article by Andrew Joseph in STAT),

Rice University said Monday that it had opened a “full investigation” into the involvement of one of its faculty members in a study that purportedly resulted in the creation of the world’s first babies born with edited DNA.

Michael Deem, a bioengineering professor at Rice, told the Associated Press in a story published Sunday that he helped work on the research in China.

Deem told the AP that he was in China when participants in the study consented to join the research. Deem also said that he had “a small stake” in and is on the scientific advisory boards of He’s two companies.

Megan Molteni in a Nov. 27, 2018 article for Wired admits she and her colleagues at the magazine may have dismissed CRISPR concerns about designer babies prematurely while shedding more light on this  latest development (Note: Links have been removed),

We said “don’t freak out,” when scientists first used Crispr to edit DNA in non-viable human embryos. When they tried it in embryos that could theoretically produce babies, we said “don’t panic.” Many years and years of boring bench science remain before anyone could even think about putting it near a woman’s uterus. Well, we might have been wrong. Permission to push the panic button granted.

Late Sunday night, a Chinese researcher stunned the world by claiming to have created the first human babies, a set of twins, with Crispr-edited DNA….

What’s perhaps most strange is not that He ignored global recommendations on conducting responsible Crispr research in humans. He also ignored his own advice to the world—guidelines that were published within hours of his transgression becoming public.

On Monday, He and his colleagues at Southern University of Science and Technology, in Shenzhen, published a set of draft ethical principles “to frame, guide, and restrict clinical applications that communities around the world can share and localize based on religious beliefs, culture, and public-health challenges.” Those principles included transparency and only performing the procedure when the risks are outweighed by serious medical need.

The piece appeared in the The Crispr Journal, a young publication dedicated to Crispr research, commentary, and debate. Rodolphe Barrangou, the journal’s editor in chief, where the peer-reviewed perspective appeared, says that the article was one of two that it had published recently addressing the ethical concerns of human germline editing, the other by a bioethicist at the University of North Carolina. Both papers’ authors had requested that their writing come out ahead of a major gene editing summit taking place this week in Hong Kong. When half-rumors of He’s covert work reached Barrangou over the weekend, his team discussed pulling the paper, but ultimately decided that there was nothing too solid to discredit it, based on the information available at the time.

Now Barrangou and his team are rethinking that decision. For one thing, He did not disclose any conflicts of interest, which is standard practice among respectable journals. It’s since become clear that not only is He at the helm of several genetics companies in China, He was actively pursuing controversial human research long before writing up a scientific and moral code to guide it.“We’re currently assessing whether the omission was a matter of ill-management or ill-intent,” says Barrangou, who added that the journal is now conducting an audit to see if a retraction might be warranted. …

“There are all sorts of questions these issues raise, but the most fundamental is the risk-benefit ratio for the babies who are going to be born,” says Hank Greely, an ethicist at Stanford University. “And the risk-benefit ratio on this stinks. Any institutional review board that approved it should be disbanded if not jailed.”

Reporting by Stat indicates that He may have just gotten in over his head and tried to cram a self-guided ethics education into a few short months. The young scientist—records indicate He is just 34—has a background in biophysics, with stints studying in the US at Rice University and in bioengineer Stephen Quake’s lab at Stanford. His resume doesn’t read like someone steeped deeply in the nuances and ethics of human research. Barrangou says that came across in the many rounds of edits He’s framework went through.

… China’s central government in Beijing has yet to come down one way or another. Condemnation would make He a rogue and a scientific outcast. Anything else opens the door for a Crispr IVF cottage industry to emerge in China and potentially elsewhere. “It’s hard to imagine this was the only group in the world doing this,” says Paul Knoepfler, a stem cell researcher at UC Davis who wrote a book on the future of designer babies called GMO Sapiens. “Some might say this broke the ice. Will others forge ahead and go public with their results or stop what they’re doing and see how this plays out?”

Here’s some of the very latest information with the researcher attempting to explain himself.

What does He have to say?

After He’s appearance at the Second International Summit on Human Genome Editing today, Nov. 27, 2018, David Cyranoski produced this article for Nature,

He Jiankui, the Chinese scientist who claims to have helped produce the first people born with edited genomes — twin girls — appeared today at a gene-editing summit in Hong Kong to explain his experiment. He gave his talk amid threats of legal action and mounting questions, from the scientific community and beyond, about the ethics of his work and the way in which he released the results.

He had never before presented his work publicly outside of a handful of videos he posted on YouTube. Scientists welcomed the fact that he appeared at all — but his talk left many hungry for more answers, and still not completely certain that He has achieved what he claims.

“There’s no reason not to believe him,” says Robin Lovell-Badge, a developmental biologist at the Francis Crick Institute in London. “I’m just not completely convinced.”

Lovell-Badge, like others at the conference, says that an independent body should confirm the test results by performing an in-depth comparison of the parents’ and childrens’ genes.

Many scientists faulted He for a lack of transparency and the seemingly cavalier nature in which he embarked on such a landmark, and potentially risky, project.

“I’m happy he came but I was really horrified and stunned when he described the process he used,” says Jennifer Doudna, a biochemist at the University of California, Berkeley and a pioneer of the CRISPR/Cas-9 gene-editing technique that He used. “It was so inappropriate on so many levels.”

He seemed shaky approaching the stage and nervous during the talk. “I think he was scared,” says Matthew Porteus, who researches genome-editing at Stanford University in California and co-hosted a question-and-answer session with He after his presentation. Porteus attributes this either to the legal pressures that He faces or the mounting criticism from the scientists and media he was about to address.

He’s talk leaves a host of other questions unanswered, including whether the prospective parents were properly informed of the risks; why He selected CCR5 when there are other, proven ways to prevent HIV; why he chose to do the experiment with couples in which the fathers have HIV, rather than mothers who have a higher chance of passing the virus on to their children; and whether the risks of knocking out CCR5 — a gene normally present in people, which could have necessary but still unknown functions — outweighed the benefits in this case.

In the discussion following He’s talk, one scientist asked why He proceeded with the experiments despite the clear consensus among scientists worldwide that such research shouldn’t be done. He didn’t answer the question.

He’s attempts to justify his actions mainly fell flat. In response to questions about why the science community had not been informed of the experiments before the first women were impregnated, he cited presentations that he gave last year at meetings at the University of California, Berkeley, and at the Cold Spring Harbor Laboratory in New York. But Doudna, who organized the Berkeley meeting, says He did not present anything that showed he was ready to experiment in people. She called his defence “disingenuous at best”.

He also said he discussed the human experiment with unnamed scientists in the United States. But Porteus says that’s not enough for such an extraordinary experiment: “You need feedback not from your two closest friends but from the whole community.” …

Pressure was mounting on He ahead of the presentation. On 27 November, the Chinese national health commission ordered the Guangdong health commission, in the province where He’s university is located, to investigate.

On the same day, the Chinese Academy of Sciences issued a statement condemning his work, and the Genetics Society of China and the Chinese Society for Stem Cell Research jointly issued a statement saying the experiment “violates internationally accepted ethical principles regulating human experimentation and human rights law”.

The hospital cited in China’s clinical-trial registry as the that gave ethical approval for He’s work posted a press release on 27 November saying it did not give any approval. It questioned the signatures on the approval form and said that the hospital’s medical-ethics committee never held a meeting related to He’s research. The hospital, which itself is under investigation by the Shenzhen health authorities following He’s revelations, wrote: “The Company does not condone the means of the Claimed Project, and has reservations as to the accuracy, reliability and truthfulness of its contents and results.”

He has not yet responded to requests for comment on these statements and investigations, nor on why the hospital was listed in the registry and the claim of apparent forged signatures.

Alice Park’s Nov. 26, 2018 article for Time magazine includes an embedded video of He’s Nov. 27, 2018 presentation at the summit meeting.

What about the politics?

Mara Hvistendahl’s Nov. 27, 2018 article about this research for Slate.com poses some geopolitical questions (Note: Links have been removed),

The informed consent agreement for He Jiankui’s experiment describes it as an “AIDS vaccine development project” and used highly technical language to describe the procedure that patients would undergo. If the reality for some Chinese patients is that such agreements are glossed over, densely written, or never read, the reality for some researchers working in the country is that the appeal of cutting-edge trials is too great to resist. It is not just Chinese scientists who can be blinded by the lure of quick breakthroughs. Several of the most notable breaches of informed consent on the mainland have involved Western researchers or co-authors. … When people say that the usual rules don’t apply in China, they are really referring to authoritarian science, not some alternative communitarian ethics.

For the many scientists in China who adhere to recognized international standards, the incident comes as a disgrace. He Jiankui now faces an ethics investigation from provincial health authorities, and his institution, Southern University of Science and Technology, was quick to issue a statement noting that He was on unpaid leave. …

It would seem that US [and from elsewhere]* scientists wanting to avoid pesky ethics requirements in the US have found that going to China could be the answer to their problems. I gather it’s not just big business that prefers deregulated environments.

Guillaume Levrier’s  (he’ studying for a PhD at the Universté Sorbonne Paris Cité) November 16, 2018 essay for The Conversation sheds some light on political will and its impact on science (Note: Links have been removed),

… China has entered a “genome editing” race among great scientific nations and its progress didn’t come out of nowhere. China has invested heavily in the natural-sciences sector over the past 20 years. The Ninth Five-Year Plan (1996-2001) mentioned the crucial importance of biotechnologies. The current Thirteenth Five-Year Plan is even more explicit. It contains a section dedicated to “developing efficient and advanced biotechnologies” and lists key sectors such as “genome-editing technologies” intended to “put China at the bleeding edge of biotechnology innovation and become the leader in the international competition in this sector”.

Chinese embryo research is regulated by a legal framework, the “technical norms on human-assisted reproductive technologies”, published by the Science and Health Ministries. The guidelines theoretically forbid using sperm or eggs whose genome have been manipulated for procreative purposes. However, it’s hard to know how much value is actually placed on this rule in practice, especially in China’s intricate institutional and political context.

In theory, three major actors have authority on biomedical research in China: the Science and Technology Ministry, the Health Ministry, and the Chinese Food and Drug Administration. In reality, other agents also play a significant role. Local governments interpret and enforce the ministries’ “recommendations”, and their own interpretations can lead to significant variations in what researchers can and cannot do on the ground. The Chinese National Academy of Medicine is also a powerful institution that has its own network of hospitals, universities and laboratories.

Another prime actor is involved: the health section of the People’s Liberation Army (PLA), which has its own biomedical faculties, hospitals and research labs. The PLA makes its own interpretations of the recommendations and has proven its ability to work with the private sector on gene editing projects. …

One other thing from Levrier’s essay,

… And the media timing is just a bit too perfect, …

Do read the essay; there’s a twist at the end.

Final thoughts and some links

If I read this material rightly, there are suspicions there may be more of this work being done in China and elsewhere. In short, we likely don’t have the whole story.

As for the ethical issues, this is a discussion among experts only, so far. The great unwashed (thee and me) are being left at the wayside. Sure, we’ll be invited to public consultations, one day,  after the big decisions have been made.

Anyone who’s read up on the history of science will tell you this kind of breach is very common at the beginning. Richard Holmes’  2008 book, ‘The Age of Wonder: How the Romantic Generation Discovered the Beauty and Terror of Science’ recounts stories of early scientists (European science) who did crazy things. Some died, some shortened their life spans; and, some irreversibly damaged their health.  They also experimented on other people. Informed consent had not yet been dreamed up.

In fact, I remember reading somewhere that the largest human clinical trial in history was held in Canada. The small pox vaccine was highly contested in the US but the Canadian government thought it was a good idea so they offered US scientists the option of coming here to vaccinate Canadian babies. This was in the 1950s and the vaccine seems to have been administered almost universally. That was a lot of Canadian babies. Thankfully, it seems to have worked out but it does seem mind-boggling today.

For all the indignation and shock we’re seeing, this is not the first time nor will it be the last time someone steps over a line in order to conduct scientific research. And, that is the eternal problem.

Meanwhile I think some of the real action regarding CRISPR and germline editing is taking place in the field (pun!) of agriculture:

My Nov. 27, 2018 posting titled: ‘Designer groundcherries by CRISPR (clustered regularly interspaced short palindromic repeats)‘ and a more disturbing Nov. 27, 2018 post titled: ‘Agriculture and gene editing … shades of the AquAdvantage salmon‘. That second posting features a company which is trying to sell its gene-editing services to farmers who would like cows that  never grow horns and pigs that never reach puberty.

Then there’s this ,

The Genetic Revolution‘, a documentary that offers relatively up-to-date information about gene editing, which was broadcast on Nov. 11, 2018 as part of The Nature of Things series on CBC (Canadian Broadcasting Corporation).

My July 17, 2018 posting about research suggesting that scientists hadn’t done enough research on possible effects of CRISPR editing titled: ‘The CRISPR ((clustered regularly interspaced short palindromic repeats)-CAS9 gene-editing technique may cause new genetic damage kerfuffle’.

My 2017 three-part series on CRISPR and germline editing:

CRISPR and editing the germline in the US (part 1 of 3): In the beginning

CRISPR and editing the germline in the US (part 2 of 3): ‘designer babies’?

CRISPR and editing the germline in the US (part 3 of 3): public discussions and pop culture

There you have it.

Added on November 30, 2018: David Cyanowski has written one final article (Nov. 30, 2018 for Nature) about He and the Second International Summit on Human Genome Editing. He did not make his second scheduled appearance at the summit, returning to China before the summit concluded. He was rebuked in a statement produced by the Summit’s organizing committee at the end of the three-day meeting. The situation with regard to his professional status in China is ambiguous. Cyanowski ends his piece with the information that the third summit will take place in London (likely in the UK) in 2021. I encourage you to read Cyanowski’s Nov. 30, 2018 article in its entirety; it’s not long.

Added on Dec. 3, 2018: The story continues. Ed Yong has written a summary of the issues to date in a Dec. 3, 2018 article for The Atlantic (even if you know the story ift’s eyeopening to see all the parts put together.

J. Benjamin Hurlbut, Associate Professor of Life Sciences at Arizona State University (ASU) and Jason Scott Robert, Director of the Lincoln Center for Applied Ethics at Arizona State University have written a provocative (and true) Dec. 3, 2018 essay titled, CRISPR babies raise an uncomfortable reality – abiding by scientific standards doesn’t guarantee ethical research, for The Conversation. h/t phys.org

*[and from elsewhere] added January 17, 2019.

Added on January 23, 2019: He has been fired by his university (Southern University of Science and Technology in Shenzhen) as announced on January 21, 2019.  David Cyranoski provides a details accounting in his January 22, 2019 article for Nature.

Boron nitride nanotubes

Most of the talk about nanotubes is focused on carbon nanotubes but there are other kinds as a May 21, 2018 Rice University news release (also received via email and on EurekAlert and in a May 21, 2018 news item on ScienceDaily), notes,

Boron nitride nanotubes are primed to become effective building blocks for next-generation composite and polymer materials based on a new discovery at Rice University – and a previous one.

Scientists at known-for-nano Rice have found a way to enhance a unique class of nanotubes using a chemical process pioneered at the university. The Rice lab of chemist Angel Martí took advantage of the Billups-Birch reaction process to enhance boron nitride nanotubes.

The work is described in the American Chemical Society journal ACS Applied Nano Materials.

Boron nitride nanotubes, like their carbon cousins, are rolled sheets of hexagonal arrays. Unlike carbon nanotubes, they’re electrically insulating hybrids made of alternating boron and nitrogen atoms.

Insulating nanotubes that can be functionalized will be a valuable building block for nanoengineering projects, Martí said. “Carbon nanotubes have outstanding properties, but you can only get them in semiconducting or metallic conducting types,” he said. “Boron nitride nanotubes are complementary materials that can fill that gap.”

Until now, these nanotubes have steadfastly resisted functionalization, the “decorating” of structures with chemical additives that allows them to be customized for applications. The very properties that give boron nitride nanotubes strength and stability, especially at high temperatures, also make them hard to modify for their use in the production of advanced materials.

But the Billups-Birch reaction developed by Rice Professor Emeritus of Chemistry Edward Billups, which frees electrons to bind with other atoms, allowed Martí and lead author Carlos de los Reyes to give the electrically inert boron nitride nanotubes a negative charge.

That, in turn, opened them up to functionalization with other small molecules, including aliphatic carbon chains.

“Functionalizing the nanotubes modifies or tunes their properties,” Martí said. “When they’re pristine they are dispersible in water, but once we attach these alkyl chains, they are extremely hydrophobic (water-avoiding). Then, if you put them in very hydrophobic solvents like those with long-chain hydrocarbons, they are more dispersible than their pristine form.

“This allows us to tune the properties of the nanotubes and will make it easier to take the next step toward composites,” he said. “For that, the materials need to be compatible.”

After he discovered the phenomenon, de los Reyes spent months trying to reproduce it reliably. “There was a period where I had to do a reaction every day to achieve reproducibility,” he said. But that turned out to be an advantage, as the process only required about a day from start to finish. “That’s the advantage over other processes to functionalize carbon nanotubes. There are some that are very effective, but they may take a few days.”

The process begins with adding pure ammonia gas to the nanotubes and cooling it to -70 degrees Celsius (-94 degrees Fahrenheit). “When it combines with sodium, lithium or potassium — we use lithium — it creates a sea of electrons,” Martí said. “When the lithium dissolves in the ammonia, it expels the electrons.”

The freed electrons quickly bind with the nanotubes and provide hooks for other molecules. De los Reyes enhanced Billups-Birch when he found that adding the alkyl chains slowly, rather than all at once, improved their ability to bind.

The researchers also discovered the process is reversible. Unlike carbon nanotubes that burn away, boron nitride nanotubes can stand the heat. Placing functionalized boron nitride tubes into a furnace at 600 degrees Celsius (1,112 degrees Fahrenheit) stripped them of the added molecules and returned them to their nearly pristine state.

“We call it defunctionalization,” Martí said. “You can functionalize them for an application and then remove the chemical groups to regain the pristine material. That’s something else the material brings that is a little different.”

The researchers have provided this pretty illustration of boron nitride nanotube,

Caption: Rice University researchers have discovered a way to ‘decorate’ electrically insulating boron nitride nanotubes with functional groups, making them more suitable for use with polymers and composite materials. Credit: Martí Research Group/Rice University

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

Chemical Decoration of Boron Nitride Nanotubes Using the Billups-Birch Reaction: Toward Enhanced Thermostable Reinforced Polymer and Ceramic Nanocomposites by Carlos A. de los Reyes, Kendahl L. Walz Mitra, Ashleigh D. Smith, Sadegh Yazdi, Axel Loredo, Frank J. Frankovsky, Emilie Ringe, Matteo Pasquali, and Angel A. Martí. ACS Appl. Nano Mater., Article ASAP DOI: 10.1021/acsanm.8b00633 Publication Date (Web): May 16, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

Removing more than 99% of crude oil from ‘produced’ water (well water)

Should you have an oil well nearby (see The Urban Oil Fields of Los Angeles in an August 28, 2014 photo essay by Alan Taylor for The Atlantic for examples of oil wells in various municipalities and cities associated with LS) , this news from Texas may interest you.

From an August 15, 2018 news item on Nanowerk,

Oil and water tend to separate, but they mix well enough to form stable oil-in-water emulsions in produced water from oil reservoirs to become a problem. Rice University scientists have developed a nanoparticle-based solution that reliably removes more than 99 percent of the emulsified oil that remains after other processing is done.
The Rice lab of chemical engineer Sibani Lisa Biswal made a magnetic nanoparticle compound that efficiently separates crude oil droplets from produced water that have proven difficult to remove with current methods.

An August 15, 2018 Rice University news release (also on EurekAlert), which originated the news item, describes the work in more detail,

Produced water [emphasis mine] comes from production wells along with oil. It often includes chemicals and surfactants pumped into a reservoir to push oil to the surface from tiny pores or cracks, either natural or fractured, deep underground. Under pressure and the presence of soapy surfactants, some of the oil and water form stable emulsions that cling together all the way back to the surface.

While methods exist to separate most of the oil from the production flow, engineers at Shell Global Solutions, which sponsored the project, told Biswal and her team that the last 5 percent of oil tends to remain stubbornly emulsified with little chance to be recovered.

“Injected chemicals and natural surfactants in crude oil can oftentimes chemically stabilize the oil-water interface, leading to small droplets of oil in water which are challenging to break up,” said Biswal, an associate professor of chemical and biomolecular engineering and of materials science and nanoengineering.

The Rice lab’s experience with magnetic particles and expertise in amines, courtesy of former postdoctoral researcher and lead author Qing Wang, led it to combine techniques. The researchers added amines to magnetic iron nanoparticles. Amines carry a positive charge that helps the nanoparticles find negatively charged oil droplets. Once they do, the nanoparticles bind the oil. Magnets are then able to pull the droplets and nanoparticles out of the solution.

“It’s often hard to design nanoparticles that don’t simply aggregate in the high salinities that are typically found in reservoir fluids, but these are quite stable in the produced water,” Biswal said.

The enhanced nanoparticles were tested on emulsions made in the lab with model oil as well as crude oil.

In both cases, researchers inserted nanoparticles into the emulsions, which they simply shook by hand and machine to break the oil-water bonds and create oil-nanoparticle bonds within minutes. Some of the oil floated to the top, while placing the test tube on a magnet pulled the infused nanotubes to the bottom, leaving clear water in between.

Best of all, Biswal said, the nanoparticles can be washed with a solvent and reused while the oil can be recovered. The researchers detailed six successful charge-discharge cycles of their compound and suspect it will remain effective for many more.

She said her lab is designing a flow-through reactor to process produced water in bulk and automatically recycle the nanoparticles. That would be valuable for industry and for sites like offshore oil rigs, where treated water could be returned to the ocean.

It seems to me that ‘produced water’ is another term for polluted water.I guess it’s the reverse to Shakespeare’s “a rose by any other name would smell as sweet” with polluted water by any other name seeming more palatable.

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

Recyclable amine-functionalized magnetic nanoparticles for efficient demulsification of crude oil-in-water emulsions by Qing Wang, Maura C. Puerto, Sumedh Warudkar, Jack Buehler, and Sibani L. Biswal. Environ. Sci.: Water Res. Technol., 2018, Advance Article DOI: 10.1039/C8EW00188J First published on 15 Aug 2018

This paper is behind a paywall.

Rice has included this image amongst others in their news release,

Rice University engineers have developed magnetic nanoparticles that separate the last droplets of oil from produced water at wells. The particles draw in the bulk of the oil and are then attracted to the magnet, as demonstrated here. Photo by Jeff Fitlow

There’s also this video, which, in my book, borders on magical,

‘Lilliputian’ skyscraper: white graphene for hydrogen storage

This story comes from Rice University (Texas, US). From a March 12, 2018 news item on Nanowerk,

Rice University engineers have zeroed in on the optimal architecture for storing hydrogen in “white graphene” nanomaterials — a design like a Lilliputian skyscraper with “floors” of boron nitride sitting one atop another and held precisely 5.2 angstroms apart by boron nitride pillars.

Caption Thousands of hours of calculations on Rice University’s two fastest supercomputers found that the optimal architecture for packing hydrogen into “white graphene” involves making skyscraper-like frameworks of vertical columns and one-dimensional floors that are about 5.2 angstroms apart. In this illustration, hydrogen molecules (white) sit between sheet-like floors of graphene (gray) that are supported by boron-nitride pillars (pink and blue). Researchers found that identical structures made wholly of boron-nitride had unprecedented capacity for storing readily available hydrogen. Credit Lei Tao/Rice University

A March 12, 2018 Rice University news release (also on EurekAlert), which originated the news item, goes into extensive detail about the work,

“The motivation is to create an efficient material that can take up and hold a lot of hydrogen — both by volume and weight — and that can quickly and easily release that hydrogen when it’s needed,”  [emphasis mine] said the study’s lead author, Rouzbeh Shahsavari, assistant professor of civil and environmental engineering at Rice.

Hydrogen is the lightest and most abundant element in the universe, and its energy-to-mass ratio — the amount of available energy per pound of raw material, for example — far exceeds that of fossil fuels. It’s also the cleanest way to generate electricity: The only byproduct is water. A 2017 report by market analysts at BCC Research found that global demand for hydrogen storage materials and technologies will likely reach $5.4 billion annually by 2021.

Hydrogen’s primary drawbacks relate to portability, storage and safety. While large volumes can be stored under high pressure in underground salt domes and specially designed tanks, small-scale portable tanks — the equivalent of an automobile gas tank — have so far eluded engineers.

Following months of calculations on two of Rice’s fastest supercomputers, Shahsavari and Rice graduate student Shuo Zhao found the optimal architecture for storing hydrogen in boron nitride. One form of the material, hexagonal boron nitride (hBN), consists of atom-thick sheets of boron and nitrogen and is sometimes called white graphene because the atoms are spaced exactly like carbon atoms in flat sheets of graphene.

Previous work in Shahsavari’s Multiscale Materials Lab found that hybrid materials of graphene and boron nitride could hold enough hydrogen to meet the Department of Energy’s storage targets for light-duty fuel cell vehicles.

“The choice of material is important,” he said. “Boron nitride has been shown to be better in terms of hydrogen absorption than pure graphene, carbon nanotubes or hybrids of graphene and boron nitride.

“But the spacing and arrangement of hBN sheets and pillars is also critical,” he said. “So we decided to perform an exhaustive search of all the possible geometries of hBN to see which worked best. We also expanded the calculations to include various temperatures, pressures and dopants, trace elements that can be added to the boron nitride to enhance its hydrogen storage capacity.”

Zhao and Shahsavari set up numerous “ab initio” tests, computer simulations that used first principles of physics. Shahsavari said the approach was computationally intense but worth the extra effort because it offered the most precision.

“We conducted nearly 4,000 ab initio calculations to try and find that sweet spot where the material and geometry go hand in hand and really work together to optimize hydrogen storage,” he said.

Unlike materials that store hydrogen through chemical bonding, Shahsavari said boron nitride is a sorbent that holds hydrogen through physical bonds, which are weaker than chemical bonds. That’s an advantage when it comes to getting hydrogen out of storage because sorbent materials tend to discharge more easily than their chemical cousins, Shahsavari said.

He said the choice of boron nitride sheets or tubes and the corresponding spacing between them in the superstructure were the key to maximizing capacity.

“Without pillars, the sheets sit naturally one atop the other about 3 angstroms apart, and very few hydrogen atoms can penetrate that space,” he said. “When the distance grew to 6 angstroms or more, the capacity also fell off. At 5.2 angstroms, there is a cooperative attraction from both the ceiling and floor, and the hydrogen tends to clump in the middle. Conversely, models made of purely BN tubes — not sheets — had less storage capacity.”

Shahsavari said models showed that the pure hBN tube-sheet structures could hold 8 weight percent of hydrogen. (Weight percent is a measure of concentration, similar to parts per million.) Physical experiments are needed to verify that capacity, but that the DOE’s ultimate target is 7.5 weight percent, and Shahsavari’s models suggests even more hydrogen can be stored in his structure if trace amounts of lithium are added to the hBN.

Finally, Shahsavari said, irregularities in the flat, floor-like sheets of the structure could also prove useful for engineers.

“Wrinkles form naturally in the sheets of pillared boron nitride because of the nature of the junctions between the columns and floors,” he said. “In fact, this could also be advantageous because the wrinkles can provide toughness. If the material is placed under load or impact, that buckled shape can unbuckle easily without breaking. This could add to the material’s safety, which is a big concern in hydrogen storage devices.

“Furthermore, the high thermal conductivity and flexibility of BN may provide additional opportunities to control the adsorption and release kinetics on-demand,” Shahsavari said. “For example, it may be possible to control release kinetics by applying an external voltage, heat or an electric field.”

I may be wrong but this “The motivation is to create an efficient material that can take up and hold a lot of hydrogen — both by volume and weight — and that can quickly and easily release that hydrogen when it’s needed, …”  sounds like a supercapacitor. One other comment, this research appears to be ‘in silico’, i.e., all the testing has been done as computer simulations and the proposed materials themselves have yet to be tested.

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

Merger of Energetic Affinity and Optimal Geometry Provides New Class of Boron Nitride Based Sorbents with Unprecedented Hydrogen Storage Capacity by Rouzbeh Shahsavari and Shuo Zhao. Small Vol. 14 Issue 10 DOI: 10.1002/smll.201702863 Version of Record online: 8 MAR 2018

© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Flat gallium (gallenene) and nanoelectronics

Another day, another 2D material. A March 9, 2018 news item on ScienceDaily announced the latest thin material from Rice university,

Scientists at Rice University and the Indian Institute of Science, Bangalore, have discovered a method to make atomically flat gallium that shows promise for nanoscale electronics.

The Rice lab of materials scientist Pulickel Ajayan and colleagues in India created two-dimensional gallenene, a thin film of conductive material that is to gallium what graphene is to carbon.

Extracted into a two-dimensional form, the novel material appears to have an affinity for binding with semiconductors like silicon and could make an efficient metal contact in two-dimensional electronic devices, the researchers said.

A March 9, 2018 Rice University news release (also on EurekAlert), which originated the news item, describes the process for creating gallenene,

Gallium is a metal with a low melting point; unlike graphene and many other 2-D structures, it cannot yet be grown with vapor phase deposition methods. Moreover, gallium also has a tendency to oxidize quickly. And while early samples of graphene were removed from graphite with adhesive tape, the bonds between gallium layers are too strong for such a simple approach.

So the Rice team led by co-authors Vidya Kochat, a former postdoctoral researcher at Rice, and Atanu Samanta, a student at the Indian Institute of Science, used heat instead of force.

Rather than a bottom-up approach, the researchers worked their way down from bulk gallium by heating it to 29.7 degrees Celsius (about 85 degrees Fahrenheit), just below the element’s melting point. That was enough to drip gallium onto a glass slide. As a drop cooled just a bit, the researchers pressed a flat piece of silicon dioxide on top to lift just a few flat layers of gallenene.

They successfully exfoliated gallenene onto other substrates, including gallium nitride, gallium arsenide, silicone and nickel. That allowed them to confirm that particular gallenene-substrate combinations have different electronic properties and to suggest that these properties can be tuned for applications.

“The current work utilizes the weak interfaces of solids and liquids to separate thin 2-D sheets of gallium,” said Chandra Sekhar Tiwary, principal investigator on the project he completed at Rice before becoming an assistant professor at the Indian Institute of Technology in Gandhinagar, India. “The same method can be explored for other metals and compounds with low melting points.”

Gallenene’s plasmonic and other properties are being investigated, according to Ajayan. “Near 2-D metals are difficult to extract, since these are mostly high-strength, nonlayered structures, so gallenene is an exception that could bridge the need for metals in the 2-D world,” he said.

Co-authors of the paper are graduate student Yuan Zhang and Associate Research Professor Robert Vajtai of Rice; Anthony Stender, a former Rice postdoctoral researcher and now an assistant professor at Ohio University; Sanjit Bhowmick, Praveena Manimunda and Syed Asif of Bruker Nano Surfaces, Minneapolis; and Rice alumnus Abhishek Singh of the Indian Institute of Science. Ajayan is chair of Rice’s Department of Materials Science and NanoEngineering, the Benjamin M. and Mary Greenwood Anderson Professor in Engineering and a professor of chemistry.

The Air Force Office of Scientific Research sponsored the research, with additional support from the Indo-US Science and Technology Forum, the government of India and a Rice Center for Quantum Materials/Smalley-Curl Postdoctoral Fellowship in Quantum Materials.

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

Atomically thin gallium layers from solid-melt exfoliation by Vidya Kochat, Atanu Samanta, Yuan Zhang, Sanjit Bhowmick, Praveena Manimunda, Syed Asif S. Asif, Anthony S. Stender, Robert Vajtai, Abhishek K. Singh, Chandra S. Tiwary, and Pulickel M. Ajayan. Science Advances 09 Mar 2018: Vol. 4, no. 3, e1701373 DOI: 10.1126/sciadv.1701373

This paper appears to be open access.

Do you want that coffee with some graphene on toast?

These scientists are excited:

For those who prefer text, here’s the Rice University Feb. 13, 2018 news release (received via email and available online here and on EurekAlert here) Note: Links have been removed),

Rice University scientists who introduced laser-induced graphene (LIG) have enhanced their technique to produce what may become a new class of edible electronics.

The Rice lab of chemist James Tour, which once turned Girl Scout cookies into graphene, is investigating ways to write graphene patterns onto food and other materials to quickly embed conductive identification tags and sensors into the products themselves.

“This is not ink,” Tour said. “This is taking the material itself and converting it into graphene.”

The process is an extension of the Tour lab’s contention that anything with the proper carbon content can be turned into graphene. In recent years, the lab has developed and expanded upon its method to make graphene foam by using a commercial laser to transform the top layer of an inexpensive polymer film.

The foam consists of microscopic, cross-linked flakes of graphene, the two-dimensional form of carbon. LIG can be written into target materials in patterns and used as a supercapacitor, an electrocatalyst for fuel cells, radio-frequency identification (RFID) antennas and biological sensors, among other potential applications.

The new work reported in the American Chemical Society journal ACS Nano demonstrated that laser-induced graphene can be burned into paper, cardboard, cloth, coal and certain foods, even toast.

“Very often, we don’t see the advantage of something until we make it available,” Tour said. “Perhaps all food will have a tiny RFID tag that gives you information about where it’s been, how long it’s been stored, its country and city of origin and the path it took to get to your table.”

He said LIG tags could also be sensors that detect E. coli or other microorganisms on food. “They could light up and give you a signal that you don’t want to eat this,” Tour said. “All that could be placed not on a separate tag on the food, but on the food itself.”

Multiple laser passes with a defocused beam allowed the researchers to write LIG patterns into cloth, paper, potatoes, coconut shells and cork, as well as toast. (The bread is toasted first to “carbonize” the surface.) The process happens in air at ambient temperatures.

“In some cases, multiple lasing creates a two-step reaction,” Tour said. “First, the laser photothermally converts the target surface into amorphous carbon. Then on subsequent passes of the laser, the selective absorption of infrared light turns the amorphous carbon into LIG. We discovered that the wavelength clearly matters.”

The researchers turned to multiple lasing and defocusing when they discovered that simply turning up the laser’s power didn’t make better graphene on a coconut or other organic materials. But adjusting the process allowed them to make a micro supercapacitor in the shape of a Rice “R” on their twice-lased coconut skin.

Defocusing the laser sped the process for many materials as the wider beam allowed each spot on a target to be lased many times in a single raster scan. That also allowed for fine control over the product, Tour said. Defocusing allowed them to turn previously unsuitable polyetherimide into LIG.

“We also found we could take bread or paper or cloth and add fire retardant to them to promote the formation of amorphous carbon,” said Rice graduate student Yieu Chyan, co-lead author of the paper. “Now we’re able to take all these materials and convert them directly in air without requiring a controlled atmosphere box or more complicated methods.”

The common element of all the targeted materials appears to be lignin, Tour said. An earlier study relied on lignin, a complex organic polymer that forms rigid cell walls, as a carbon precursor to burn LIG in oven-dried wood. Cork, coconut shells and potato skins have even higher lignin content, which made it easier to convert them to graphene.

Tour said flexible, wearable electronics may be an early market for the technique. “This has applications to put conductive traces on clothing, whether you want to heat the clothing or add a sensor or conductive pattern,” he said.

Rice alumnus Ruquan Ye is co-lead author of the study. Co-authors are Rice graduate student Yilun Li and postdoctoral fellow Swatantra Pratap Singh and Professor Christopher Arnusch of Ben-Gurion University of the Negev, Israel. Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of computer science and of materials science and nanoengineering at Rice.

The Air Force Office of Scientific Research supported the research.

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

Laser-Induced Graphene by Multiple Lasing: Toward Electronics on Cloth, Paper, and Food by Yieu Chyan, Ruquan Ye†, Yilun Li, Swatantra Pratap Singh, Christopher J. Arnusch, and James M. Tour. ACS Nano DOI: 10.1021/acsnano.7b08539 Publication Date (Web): February 13, 2018

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

h/t Feb. 13, 2018 news item on Nanowerk

How small can a carbon nanotube get before it stops being ‘electrical’?

Research, which began as an attempt to get reproducible electronics (?) measurements, yielded some unexpected results according ta January 3, 2018 news item on phys.org,

Carbon nanotubes bound for electronics not only need to be as clean as possible to maximize their utility in next-generation nanoscale devices, but contact effects may limit how small a nano device can be, according to researchers at the Energy Safety Research Institute (ESRI) at Swansea University [UK] in collaboration with researchers at Rice University [US].

ESRI Director Andrew Barron, also a professor at Rice University in the USA, and his team have figured out how to get nanotubes clean enough to obtain reproducible electronic measurements and in the process not only explained why the electrical properties of nanotubes have historically been so difficult to measure consistently, but have shown that there may be a limit to how “nano” future electronic devices can be using carbon nanotubes.

Swansea University Issued a January 3, 2018 press release (also on EurekAlert), which originated the news item, explains the work in more detail,

Like any normal wire, semiconducting nanotubes are progressively more resistant to current along their length. But conductivity measurements of nanotubes over the years have been anything but consistent. The ESRI team wanted to know why.

“We are interested in the creation of nanotube based conductors, and while people have been able to make wires their conduction has not met expectations. We were interested in determining the basic sconce behind the variability observed by other researchers.”

They discovered that hard-to-remove contaminants — leftover iron catalyst, carbon and water — could easily skew the results of conductivity tests. Burning them away, Barron said, creates new possibilities for carbon nanotubes in nanoscale electronics.

The new study appears in the American Chemical Society journal Nano Letters.

The researchers first made multiwalled carbon nanotubes between 40 and 200 nanometers in diameter and up to 30 microns long. They then either heated the nanotubes in a vacuum or bombarded them with argon ions to clean their surfaces.

They tested individual nanotubes the same way one would test any electrical conductor: By touching them with two probes to see how much current passes through the material from one tip to the other. In this case, their tungsten probes were attached to a scanning tunneling microscope.

In clean nanotubes, resistance got progressively stronger as the distance increased, as it should. But the results were skewed when the probes encountered surface contaminants, which increased the electric field strength at the tip. And when measurements were taken within 4 microns of each other, regions of depleted conductivity caused by contaminants overlapped, further scrambling the results.

“We think this is why there’s such inconsistency in the literature,” Barron said.

“If nanotubes are to be the next generation lightweight conductor, then consistent results, batch-to-batch, and sample-to-sample, is needed for devices such as motors and generators as well as power systems.”

Annealing the nanotubes in a vacuum above 200 degrees Celsius (392 degrees Fahrenheit) reduced surface contamination, but not enough to eliminate inconsistent results, they found. Argon ion bombardment also cleaned the tubes, but led to an increase in defects that degrade conductivity.

Ultimately they discovered vacuum annealing nanotubes at 500 degrees Celsius (932 Fahrenheit) reduced contamination enough to accurately measure resistance, they reported.

To now, Barron said, engineers who use nanotube fibers or films in devices modify the material through doping or other means to get the conductive properties they require. But if the source nanotubes are sufficiently decontaminated, they should be able to get the right conductivity by simply putting their contacts in the right spot.

“A key result of our work was that if contacts on a nanotube are less than 1 micron apart, the electronic properties of the nanotube changes from conductor to semiconductor, due to the presence of overlapping depletion zones” said Barron, “this has a potential limiting factor on the size of nanotube based electronic devices – this would limit the application of Moore’s law to nanotube devices.”

Chris Barnett of Swansea is lead author of the paper. Co-authors are Cathren Gowenlock and Kathryn Welsby, and Rice alumnus Alvin Orbaek White of Swansea. Barron is the Sêr Cymru Chair of Low Carbon Energy and Environment at Swansea and the Charles W. Duncan Jr.–Welch Professor of Chemistry and a professor of materials science and nanoengineering at Rice.

The Welsh Government Sêr Cymru National Research Network in Advanced Engineering and Materials, the Sêr Cymru Chair Program, the Office of Naval Research and the Robert A. Welch Foundation supported the research.

Rice University has published a January 4, 2018 Rice University news release (also on EurekAlert), which is almost (95%) identical to the press release from Swansea. That’s a bit unusual as collaborating institutions usually like to focus on their unique contributions to the research, hence, multiple news/press releases.

Dexter Johnson, in a January 11, 2018 post on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website,  adds a detail or two while writing in an accessible style.

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

Spatial and Contamination-Dependent Electrical Properties of Carbon Nanotubes by Chris J. Barnett, Cathren E. Gowenlock, Kathryn Welsby, Alvin Orbaek White, and Andrew R. Barron. Nano Lett., Article ASAP DOI: 10.1021/acs.nanolett.7b03390 Publication Date (Web): December 19, 2017

Copyright © 2017 American Chemical Society

This paper is behind a paywall.

Resizing viral peptides for nanoscale drug delivery system

A January 9, 2018 news item on Nanowerk sheds some light on the research (Note: A link has been removed),

By chipping away at a viral protein, Rice University scientists have discovered a path toward virus-like, nanoscale devices that may be able to deliver drugs to cells.

The protein is one of three that make up the protective shell, called the capsid, of natural adeno-associated viruses (AAV). By making progressively smaller versions of the protein, the researchers made capsids with unique abilities and learned a great deal about AAV’s mechanisms.

The research appears in the American Chemical Society journal ACS Nano (“Reprogramming the Activatable Peptide Display Function of Adeno-Associated Virus Nanoparticles”).
programmable adeno-associated viruses

Rice University bioengineers have developed programmable adeno-associated viruses by modifying one of three proteins that assemble into a tough shell called a capsid. In this illustration, blue subunits in the capsid represent the protein VP3 and green subunits represent a truncated mutant of VP2.

Here’s an image illustrating the work,

Rice University bioengineers have developed programmable adeno-associated viruses by modifying one of three proteins that assemble into a tough shell called a capsid. In this illustration, blue subunits in the capsid represent the protein VP3 and green subunits represent a truncated mutant of VP2. From top to bottom: a VP3-only capsid that does not display any peptides; a mosaic capsid with a majority of VP3 and small amount of the VP2 mutant that shows a low level of activable peptide display; a mosaic capsid with equal amounts of VP3 and VP2 mutant that shows a high level of activable peptide display; and a homomeric VP2 mutant capsid with a high level of constant, brush-like peptide display. For a larger version, click on the image. Illustration by Nicole Thadani Courtesy: Rice University

A January 8, 2018 Rice University news release (also on EurekAlert), which originated the news item, expands on the story,

Rice bioengineer Junghae Suh studies the manipulation of nondisease-causing AAVs to deliver helpful cargoes like chemotherapy drugs. Her research has led to the development of viruses that can be triggered by light or by extracellular proteases associated with certain diseases.

AAVs are small — about 25 nanometers — and contain a single strand of DNA inside tough capsids that consist of a mosaic of proteins known as VP1, VP2 and VP3. AAVs have been used to deliver gene-therapy payloads, but nobody has figured out how AAV capsids physically reconfigure themselves when triggered by external stimuli, Suh said. That was the starting point for her lab.

“This virus has intrinsic peptide (small protein) domains hidden inside the capsid,” she said. “When the virus infects a cell, it senses the low pH and other endosomal factors, and these peptide domains pop out onto the surface of the virus capsid.

“This conformational change, which we termed an ‘activatable peptide display,’ is important for the virus because the externalized domains break down the endosomal membrane and allow the virus to escape into the cytoplasm,” Suh said. “In addition, nuclear localization sequences in those domains allow the virus to transit into the nucleus. We believed we could replace that functionality with something else.”

Suh and lead author and Rice graduate student Nicole Thadani think their mutant AAVs can become “biocomputing nanoparticles” that detect and process environmental inputs and produce controllable outputs. Modifying the capsid is the first step.

Of the three natural capsid proteins, only VP1 and VP2 can be triggered to expose their functional peptides, but neither can make a capsid on its own. Shorter VP3s can form capsids by themselves, but do not display peptides. In natural AAVs, VP3 proteins outnumber each of their compadres 10-to-1.

That limits the number of peptides that can be exposed, so Suh, Thadani and their co-authors set out to change the ratio. That led them to truncate VP2 and synthesize mosaic capsids with VP3, resulting in successful alteration of the number of exposed peptides. Based on previous research, they inserted a common hexahistidine tag that made it easy to monitor the surface display of the peptide region.

“We wanted to boost the protein’s activable property beyond what occurs in the native virus capsid,” Thadani said. “Rather than displaying just five copies of the peptide per capsid, now we may be able to display 20 or 30 and get more of the bioactivity that we want.”

They then made a truncated VP2 able to form a capsid on its own. “The results were quite surprising, and not obvious to us,” Suh said. “We chopped down that VP2 component enough to form what we call a homomeric capsid, where the entire capsid is made up of just that mutant subunit. That gave us viruses that appear to have peptide ‘brushes’ that are always on the surface.

“A viral structure like that has never been seen in nature,” she said. “We got a particle with this peptide brush, with loose ends everywhere. Now we want to know if we can use these loose ends to attach other things or carry out other functions.”

Homomeric AAVs display as many as 60 peptides, while mosaic AAVs could be programmed to respond to stimuli specific to particular cells or tissues and display a smaller desired number of peptides, the researchers said.

“Viruses have evolved to invade cells very effectively,” Suh said. “We want to use our virus as a nanoparticle platform to deliver protein- or peptide-based therapeutics more efficiently into cells. We want to harness what nature has already created, tweak it a little bit and use it for our purposes.”

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

Reprogramming the Activatable Peptide Display Function of Adeno-Associated Virus Nanoparticles by Nicole N. Thadani, Christopher Dempsey, Julia Zhao, Sonya M. Vasquez, and Junghae Suh. ACS Nano, Article ASAP DOI: 10.1021/acsnano.7b07804 Publication Date (Web): December 26, 2017

Copyright © 2017 American Chemical Society

This paper is behind a paywall.

Carbon nanotubes for enhanced wheat growth?

It’s been a long time (Oct. 22, 2009 posting; scroll down about 20% of the way) since I’ve written about carbon nanotubes and their possible use in agriculture but now a December 6, 2017 news item on ScienceDaily raises the topic again,

The introduction of purified carbon nanotubes appears to have a beneficial effect on the early growth of wheatgrass, according to Rice University scientists. But in the presence of contaminants, those same nanotubes could do great harm.

The Rice lab of chemist Andrew Barron grew wheatgrass in a hydroponic garden to test the potential toxicity of nanoparticles on the plant. To their surprise, they found one type of particle dispersed in water helped the plant grow bigger and faster.

They suspect the results spring from nanotubes’ natural hydrophobic (water-avoiding) nature that in one experiment apparently facilitated the plants’ enhanced uptake of water.

The research appears in the Royal Society of Chemistry journal Environmental Science: Nano.

A December 6, 2017 Rice University news release (also on EurekAlert), which originated the news item, expands on the theme,

The lab mounted the small-scale study with the knowledge that the industrial production of nanotubes will inevitably lead to their wider dispersal in the environment. The study cited rapid growth in the market for nanoparticles in drugs, cosmetic, fabrics, water filters and military weapons, with thousands of tons produced annually.

Despite their widespread use, Barron said few researchers have looked at the impact of environmental nanoparticles — whether natural or man-made — on plant growth.

The researchers planted wheatgrass seeds in multiple replicates in cotton wool and fed them with dispersions that contained raw single-walled or multi-walled nanotubes, purified single-walled nanotubes or iron oxide nanoparticles that mimicked leftover catalyst often attached to nanotubes. The solutions were either water or tetrahydrofuran (THF), an industrial solvent. Some of the seeds were fed pure water or THF as a control.

Rice University researchers tested the effects of carbon nanotubes on the growth of wheatgrass. While some showed no effect, purified single-walled nanotubes in water (5) enhanced the plants' growth, while the same nanotubes in a solvent (6) retarded their development. The photos at left show the plants after four days and at right after eight days, with odd-numbered plants growing in water and evens in a solvent. Numbers 1 and 2 are controls without nanotubes; 3-4 contain raw single-walled tubes; 5-6 purified single-walled tubes; 7-8 raw multi-walled tubes; 9-10 low-concentration iron-oxide nanoparticles and 11-12 high-concentration iron-oxide nanoparticles.

Rice University researchers tested the effects of carbon nanotubes on the growth of wheatgrass. While some showed no effect, purified single-walled nanotubes in water (5) enhanced the plants’ growth, while the same nanotubes in a solvent (6) retarded their development. The photos at left show the plants after four days and at right after eight days, with odd-numbered plants growing in water and evens in a solvent. Numbers 1 and 2 are controls without nanotubes; 3-4 contain raw single-walled tubes; 5-6 purified single-walled tubes; 7-8 raw multi-walled tubes; 9-10 low-concentration iron-oxide nanoparticles and 11-12 high-concentration iron-oxide nanoparticles. Click on the image for a larger version. Photos by Seung Mook Lee

After eight days, the plantings showed that purified single-walled nanotubes in water enhanced the germination rate and shoot growth of wheatgrass, which grew an average of 13 percent larger than plants in plain water. Raw single- and multi-walled nanotubes and particles in either solution had little effect on the plants’ growth, they found.

However, purified single-walled nanotubes in THF retarded plant development by 45 percent compared to single-walled nanotubes in water, suggesting the nanotubes act as a carrier for the toxic substance.

The concern, Barron said, is that if single-walled nanotubes combine with organic pollutants like pesticides, industrial chemicals or solvents in the environment, they may concentrate and immobilize the toxins and enhance their uptake by plants.

Nothing seen in the limited study indicated whether carbon nanotubes in the environment, and potentially in plants, will rise up the food chain and be harmful to humans, he said.

On the other hand, the researchers said it may be worth looking at whether hydrophobic substrates that mimic the positive effects observed in single-walled nanotubes could be used for high-efficiency channeling of water to seeds.

“Our work confirms the importance of thinking of nanomaterials as part of a system rather in isolation,” Barron said. “It is the combination with other compounds that is important to understand.”

Seung Mook Lee, a former visiting student research assistant from Memorial High School in Houston and now an undergraduate student at the University of California, Berkeley, is lead author of the paper. Co-authors are Rice research scientist Pavan Raja and graduate student Gibran Esquenazi. Barron is the Charles W. Duncan Jr.–Welch Professor of Chemistry and a professor of materials science and nanoengineering at Rice and the Sêr Cymru Chair of Low Carbon Energy and Environment at Swansea University, Wales (UK).

The Welsh Government Sêr Cymru Program and the Robert A. Welch Foundation supported the research.

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

Effect of raw and purified carbon nanotubes and iron oxide nanoparticles on the growth of wheatgrass prepared from the cotyledons of common wheat (triticum aestivum) by Seung Mook Lee, Pavan M. V. Raja, Gibran L. Esquenazi, and Andrew R. Barron. Environ. Sci.: Nano, 2018, Advance Article DOI: 10.1039/C7EN00680B First published on 09 Nov 2017

This paper appears to be behind a paywall.

Using only sunlight to desalinate water

The researchers seem to believe that this new desalination technique could be a game changer. From a June 20, 2017 news item on Azonano,

An off-grid technology using only the energy from sunlight to transform salt water into fresh drinking water has been developed as an outcome of the effort from a federally funded research.

The desalination system uses a combination of light-harvesting nanophotonics and membrane distillation technology and is considered to be the first major innovation from the Center for Nanotechnology Enabled Water Treatment (NEWT), which is a multi-institutional engineering research center located at Rice University.

NEWT’s “nanophotonics-enabled solar membrane distillation” technology (NESMD) integrates tried-and-true water treatment methods with cutting-edge nanotechnology capable of transforming sunlight to heat. …

A June 19, 2017 Rice University news release, which originated the news item, expands on the theme,

More than 18,000 desalination plants operate in 150 countries, but NEWT’s desalination technology is unlike any other used today.

“Direct solar desalination could be a game changer for some of the estimated 1 billion people who lack access to clean drinking water,” said Rice scientist and water treatment expert Qilin Li, a corresponding author on the study. “This off-grid technology is capable of providing sufficient clean water for family use in a compact footprint, and it can be scaled up to provide water for larger communities.”

The oldest method for making freshwater from salt water is distillation. Salt water is boiled, and the steam is captured and run through a condensing coil. Distillation has been used for centuries, but it requires complex infrastructure and is energy inefficient due to the amount of heat required to boil water and produce steam. More than half the cost of operating a water distillation plant is for energy.

An emerging technology for desalination is membrane distillation, where hot salt water is flowed across one side of a porous membrane and cold freshwater is flowed across the other. Water vapor is naturally drawn through the membrane from the hot to the cold side, and because the seawater need not be boiled, the energy requirements are less than they would be for traditional distillation. However, the energy costs are still significant because heat is continuously lost from the hot side of the membrane to the cold.

“Unlike traditional membrane distillation, NESMD benefits from increasing efficiency with scale,” said Rice’s Naomi Halas, a corresponding author on the paper and the leader of NEWT’s nanophotonics research efforts. “It requires minimal pumping energy for optimal distillate conversion, and there are a number of ways we can further optimize the technology to make it more productive and efficient.”

NEWT’s new technology builds upon research in Halas’ lab to create engineered nanoparticles that harvest as much as 80 percent of sunlight to generate steam. By adding low-cost, commercially available nanoparticles to a porous membrane, NEWT has essentially turned the membrane itself into a one-sided heating element that alone heats the water to drive membrane distillation.

“The integration of photothermal heating capabilities within a water purification membrane for direct, solar-driven desalination opens new opportunities in water purification,” said Yale University ‘s Menachem “Meny” Elimelech, a co-author of the new study and NEWT’s lead researcher for membrane processes.

In the PNAS study, researchers offered proof-of-concept results based on tests with an NESMD chamber about the size of three postage stamps and just a few millimeters thick. The distillation membrane in the chamber contained a specially designed top layer of carbon black nanoparticles infused into a porous polymer. The light-capturing nanoparticles heated the entire surface of the membrane when exposed to sunlight. A thin half-millimeter-thick layer of salt water flowed atop the carbon-black layer, and a cool freshwater stream flowed below.

Li, the leader of NEWT’s advanced treatment test beds at Rice, said the water production rate increased greatly by concentrating the sunlight. “The intensity got up 17.5 kilowatts per meter squared when a lens was used to concentrate sunlight by 25 times, and the water production increased to about 6 liters per meter squared per hour.”

Li said NEWT’s research team has already made a much larger system that contains a panel that is about 70 centimeters by 25 centimeters. Ultimately, she said, NEWT hopes to produce a modular system where users could order as many panels as they needed based on their daily water demands.

“You could assemble these together, just as you would the panels in a solar farm,” she said. “Depending on the water production rate you need, you could calculate how much membrane area you would need. For example, if you need 20 liters per hour, and the panels produce 6 liters per hour per square meter, you would order a little over 3 square meters of panels.”

Established by the National Science Foundation in 2015, NEWT aims to develop compact, mobile, off-grid water-treatment systems that can provide clean water to millions of people who lack it and make U.S. energy production more sustainable and cost-effective. NEWT, which is expected to leverage more than $40 million in federal and industrial support over the next decade, is the first NSF Engineering Research Center (ERC) in Houston and only the third in Texas since NSF began the ERC program in 1985. NEWT focuses on applications for humanitarian emergency response, rural water systems and wastewater treatment and reuse at remote sites, including both onshore and offshore drilling platforms for oil and gas exploration.

There is a video but it is focused on the NEWT center rather than any specific water technologies,

For anyone interested in the technology, here’s a link to and a citation for the researchers’ paper,

Nanophotonics-enabled solar membrane distillation for off-grid water purification by Pratiksha D. Dongare, Alessandro Alabastri, Seth Pedersen, Katherine R. Zodrow, Nathaniel J. Hogan, Oara Neumann, Jinjian Wu, Tianxiao Wang, Akshay Deshmukh,f, Menachem Elimelech, Qilin Li, Peter Nordlander, and Naomi J. Halas. PNAS {Proceedings of the National Academy of Sciences] doi: 10.1073/pnas.1701835114 June 19, 2017

This paper appears to be open access.