Photosynthesis provides energy for the vast majority of life on Earth. But chlorophyll, the green pigment that plants use to harvest sunlight, is relatively inefficient. To enable humans to capture more of the sun’s energy than natural photosynthesis can, scientists have taught bacteria to cover themselves in tiny, highly efficient solar panels to produce useful compounds.
“Rather than rely on inefficient chlorophyll to harvest sunlight, I’ve taught bacteria how to grow and cover their bodies with tiny semiconductor nanocrystals,” says Kelsey K. Sakimoto, Ph.D., who carried out the research in the lab of Peidong Yang, Ph.D. “These nanocrystals are much more efficient than chlorophyll and can be grown at a fraction of the cost of manufactured solar panels.”
Humans increasingly are looking to find alternatives to fossil fuels as sources of energy and feedstocks for chemical production. Many scientists have worked to create artificial photosynthetic systems to generate renewable energy and simple organic chemicals using sunlight. Progress has been made, but the systems are not efficient enough for commercial production of fuels and feedstocks.
Research in Yang’s lab at the University of California, Berkeley, where Sakimoto earned his Ph.D., focuses on harnessing inorganic semiconductors that can capture sunlight to organisms such as bacteria that can then use the energy to produce useful chemicals from carbon dioxide and water. “The thrust of research in my lab is to essentially ‘supercharge’ nonphotosynthetic bacteria by providing them energy in the form of electrons from inorganic semiconductors, like cadmium sulfide, that are efficient light absorbers,” Yang says. “We are now looking for more benign light absorbers than cadmium sulfide to provide bacteria with energy from light.”
Sakimoto worked with a naturally occurring, nonphotosynthetic bacterium, Moorella thermoacetica, which, as part of its normal respiration, produces acetic acid from carbon dioxide (CO2). Acetic acid is a versatile chemical that can be readily upgraded to a number of fuels, polymers, pharmaceuticals and commodity chemicals through complementary, genetically engineered bacteria.
When Sakimoto fed cadmium and the amino acid cysteine, which contains a sulfur atom, to the bacteria, they synthesized cadmium sulfide (CdS) nanoparticles, which function as solar panels on their surfaces. The hybrid organism, M. thermoacetica-CdS, produces acetic acid from CO2, water and light. “Once covered with these tiny solar panels, the bacteria can synthesize food, fuels and plastics, all using solar energy,” Sakimoto says. “These bacteria outperform natural photosynthesis.”
The bacteria operate at an efficiency of more than 80 percent, and the process is self-replicating and self-regenerating, making this a zero-waste technology. “Synthetic biology and the ability to expand the product scope of CO2 reduction will be crucial to poising this technology as a replacement, or one of many replacements, for the petrochemical industry,” Sakimoto says.
So, do the inorganic-biological hybrids have commercial potential? “I sure hope so!” he says. “Many current systems in artificial photosynthesis require solid electrodes, which is a huge cost. Our algal biofuels are much more attractive, as the whole CO2-to-chemical apparatus is self-contained and only requires a big vat out in the sun.” But he points out that the system still requires some tweaking to tune both the semiconductor and the bacteria. He also suggests that it is possible that the hybrid bacteria he created may have some naturally occurring analog. “A future direction, if this phenomenon exists in nature, would be to bioprospect for these organisms and put them to use,” he says.
For more insight into the work, check out Dexter Johnson’s Aug. 22, 2017 posting on his Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website),
“It’s actually a natural, overlooked feature of their biology,” explains Sakimoto in an e-mail interview with IEEE Spectrum. “This bacterium has a detoxification pathway, meaning if it encounters a toxic metal, like cadmium, it will try to precipitate it out, thereby detoxifying it. So when we introduce cadmium ions into the growth medium in which M. thermoacetica is hanging out, it will convert the amino acid cysteine into sulfide, which precipitates out cadmium as cadmium sulfide. The crystals then assemble and stick onto the bacterium through normal electrostatic interactions.”
I’ve just excerpted one bit, there’s more in Dexter’s posting.
Updates on a previous glowing plants and animals posting
In a May 5, 2013 posting I featured a Kickstarter campaign for a synthetic biology project focused on plants that emit light in the dark. I also mentioned Eduardo Kac (pronounced Katz) and his art project/transgenic bunny called Alba. At the time, I did not realize that Alba had been declared dead in 2002 adding more controversy to an already controversial topice according to Kristen Philipkoski in an Aug. 12, 2002 article (how did I miss this article in 2013?) for Wired magazine (Note: Links have been removed),
Alba, the glowing rabbit that made headlines two years ago for being, well, a glowing rabbit, has met an untimely death, according to the French researcher who genetically engineered her.
Alba the glowing rabbit was 4 years old. Or 2-1/2, depending on who’s talking.
The bunny died about a month ago for reasons that are not clear, said Louis-Marie Houdebine, a genetic researcher at France’s National Institute of Agronomic Research.
“I was informed one day that bunny was dead without any reason,” Houdebine said. “So, rabbits die often. It was about 4 years old, which is a normal lifespan in our facilities.”
Alba was an albino rabbit engineered by splicing the green fluorescent protein (GFP) of a jellyfish into her genome. Houdebine said he did not believe the GFP gene played a role in the animal’s demise.
Eduardo Kac, the artist who created a flurry by making her a work of art, doesn’t buy it, however.
First, Alba’s not 4, she’s 2-1/2, Kac says (a rabbit’s lifespan is up to 12 years), because she was bred by Houdebine specifically for him in January 2000.
Houdebine says he simply picked a rabbit with a gentle disposition that was already in his lab.
Second, he believes Houdebine might be declaring the bunny gone in order to put an end to a two-year, unwelcome barrage of media attention.
If she really is dead, Kac will never realize the final phase of his project, which was to take Alba home and keep her as a pet.
Kac says he and Houdebine originally collaborated on the GFP bunny project, until Houdebine’s director put the kibosh on it.
“My director did not understand,” Houdebine said. “He said I should not give the rabbit (to someone) outside the lab.”
Houdebine said that yes, they spoke about preliminary plans for Kac to use the bunny for his project and take it to an art show in Avignon. But he denies he bred an animal specifically for Kac.
Houdebine says he would not have agreed to engineer one animal specifically for any artist.
This disputed point has led fellow artists and critics to question whether Kac can rightly take credit for the Alba project.
But Kac insists that Houdebine did, in fact, agree to make the bunny specifically for him.
Kac found out sometime in mid-2000 that Houdebine’s director had a problem with the project and would not allow the rabbit to be taken from the lab.
Houdebine was initially apologetic, Kac said. But after an article ran on the front page of the Boston Globe on Sept. 17, 2000, their relationship cooled.
Houdebine and his director were opposed to the now-famous, brilliantly glowing photograph of Alba. They and other researchers say the rabbit doesn’t actually glow so brightly and uniformly.
“Kac fabricated data for his personal use,” Houdebine said. “This is why we totally stopped any contact with him.”
“The scientific fact is that the rabbit is not green,” he said. “He should have never published that. This was very disagreeable for me.”
Kac believes the scientists were simply afraid of public criticism. Meanwhile, he wanted to do the opposite – to encourage discourse on the transgenic rabbit.
“This director refuses to participate openly in a debate about what is done with public money,” he said. “It’s very easy to fear and reject what you don’t know. As long as they continue to isolate themselves, this mistrust will continue.”
The eyes and ears of the rabbit are green under ultraviolet light, Houdebine said, but the fur does not glow, because it’s dead tissue that doesn’t express the gene. Only if the rabbit were shaved would the body glow, he said.
Philipkosk’s article provides some insight into the interface between art and science and is worth reading in its entirety if you have the time.
I’ve also found an update for the glowing plants Kickstarter campaign in an April 20, 2017 article by Sarah Zhang for The Atlantic (Note: Links have been removed),
The latest update came quietly on Tuesday night [April 18, 2017?]. “We’re sorry to say that we have reached a significant transition point,” wrote the Glowing Plant project’s creator, Antony Evans. This “transition point” was more of an endpoint: The project had run out of money. The quest to genetically engineer a glow-in-the-dark plant was no more.
Four years ago, the Glowing Plant project raised nearly half a million dollars on Kickstarter, easily blowing past its initial ask of $65,000. Of course it did. The vision it presented was such potent fantasy. “What if,” Evans asked over swelling music in the pitch video, “we use trees to light our streets instead of street lamps?” What if you could get lighting without electricity? What if the natural world glowed like in Avatar?
This romantic vision so perfectly encapsulated the promises of synthetic biology, a field that treats the natural world as another system to be designed and engineered. In this case, synthetic biology became a possible solution to one of the world’s most pressing energy problems: electricity generation. Plus, it sounded really damn cool.
The Kickstarter campaign only promised a small, potted glowing plant to it backers, and I doubt many backers actually harbored illusions about trees lighting up the night sky soon. But backing the project was a small way to buy into a much grander vision.
At a time when “genetically modified organism,” or GMO, is such a poisoned phrase, the project’s crowdfunding success seemed to suggest that a pervasive if vague distrust of genetic modification might be countered by the sense of wonder for a glowing plant. (As the Kickstarter campaign grew, though, environmental groups raised questions and the crowdfunding site later banned giving away genetically modified organisms.)
The team also encountered the hard realities of engineering even a small plant that glows. “We did not anticipate some of the unknown technical challenges that we would get into,” Evans told me. (Plenty of scientists at the time were skeptical of the project’s timeline, though.) Evans is an MBA with a background in mobile apps, though his two original cofounders, who have both since left the project, had backgrounds in synthetic biology.
To get the plant to glow well, the research team had to insert six genes. But they never could get all six in at once. At best, some plants glowed very dimly. (The photo above of the glowing plant is a long exposure, making it appear much brighter than it actually is.) Evans says that he realizes now trying to insert six genes into a complex organism like a plant—rather than single-celled bacteria or yeast—was premature.
“I’m really afraid of disappointing that 16-year-old who saw this and imagined a bright wonderful future, of jading and disappointing people,” he says. Despite a few angry backers asking for a refund, most of the comments under the Kickstarter update so far have been supportive. The project had been providing regular, detailed updates on the difficulty of engineering the plants. The latest update was its 67th.
Zhang’s article goes on to detail other synthetic biology projects, which are showing some promise.
When you take this work into consideration with CRISPR-CAS9 and the beginnings of genetic germline editing, the question has to be asked: Will public discussion (if there’s any) be considered upstream (early in the process) or downstream (after the work has been done)? Public engagement professionals tend to favour upstream discussions, i.e., before people start demanding fear-based policy.
There were hints even while it was happening that the ‘Green Revolution’ of the 1960s was not all it was touted to be. (For those who haven’t come across the term before, the Green Revolution was a better way to farm, a way that would feed everyone on earth. Or, that was the dream.)
Perhaps this time, they’ll be more successful. From a Jan. 15, 2017 news item on ScienceDaily, which offers a perspective on the ‘Green Revolution’ that differs from mine,
The “Green Revolution” of the ’60s and ’70s has been credited with helping to feed billions around the world, with fertilizers being one of the key drivers spurring the agricultural boom. But in developing countries, the cost of fertilizer remains relatively high and can limit food production. Now researchers report in the journal ACS Nano a simple way to make a benign, more efficient fertilizer that could contribute to a second food revolution.
Farmers often use urea, a rich source of nitrogen, as fertilizer. Its flaw, however, is that it breaks down quickly in wet soil and forms ammonia. The ammonia is washed away, creating a major environmental issue as it leads to eutrophication of water ways and ultimately enters the atmosphere as nitrogen dioxide, the main greenhouse gas associated with agriculture. This fast decomposition also limits the amount of nitrogen that can get absorbed by crop roots and requires farmers to apply more fertilizer to boost production. However, in low-income regions where populations continue to grow and the food supply is unstable, the cost of fertilizer can hinder additional applications and cripple crop yields. Nilwala Kottegoda, Veranja Karunaratne, Gehan Amaratunga and colleagues wanted to find a way to slow the breakdown of urea and make one application of fertilizer last longer.
To do this, the researchers developed a simple and scalable method for coating hydroxyapatite (HA) nanoparticles with urea molecules. HA is a mineral found in human and animal tissues and is considered to be environmentally friendly. In water, the hybridization of the HA nanoparticles and urea slowly released nitrogen, 12 times slower than urea by itself. Initial field tests on rice farms showed that the HA-urea nanohybrid lowered the need for fertilizer by one-half. The researchers say their development could help contribute to a new green revolution to help feed the world’s continuously growing population and also improve the environmental sustainability of agriculture.
Here’s a link to and a citation for the paper,
Urea-Hydroxyapatite Nanohybrids for Slow Release of Nitrogen by Nilwala Kottegoda, Chanaka Sandaruwan, Gayan Priyadarshana, Asitha Siriwardhana, Upendra A. Rathnayake, Danushka Madushanka Berugoda Arachchige, Asurusinghe R. Kumarasinghe, Damayanthi Dahanayake, Veranja Karunaratne, and Gehan A. J. Amaratunga. ACS Nano, Article ASAP DOI: 10.1021/acsnano.6b07781 Publication Date (Web): January 25, 2017
Curcumin, a compound in turmeric, continues to be hailed as a natural treatment for a wide range of health conditions, including cancer and Alzheimer’s disease. But a new review of the scientific literature on curcumin has found it’s probably not all it’s ground up to be. The report in ACS’ Journal of Medicinal Chemistry instead cites evidence that, contrary to numerous reports, the compound has limited — if any — therapeutic benefit.
Turmeric, a spice often added to curries and mustards because of its distinct flavor and color, has been used for centuries in traditional medicine. Since the early 1990’s, scientists have zeroed in on curcumin, which makes up about 3 to 5 percent of turmeric, as the potential constituent that might give turmeric its health-boosting properties. More than 120 clinical trials to test these claims have been or are in the process of being run by clinical investigators. To get to the root of curcumin’s essential medicinal chemistry, the research groups of Michael A. Walters and Guido F. Pauli teamed up to extract key findings from thousands of scientific articles on the topic.
The researchers’ review of the vast curcumin literature provides evidence that curcumin is unstable under physiological conditions and not readily absorbed by the body, properties that make it a poor therapeutic candidate. Additionally, they could find no evidence of a double-blind, placebo-controlled clinical trial on curcumin to support its status as a potential cure-all. But, the authors say, this doesn’t necessarily mean research on turmeric should halt [emphasis mine]. Turmeric extracts and preparations could have health benefits, although probably not for the number of conditions currently touted. The researchers suggest that future studies should take a more holistic approach to account for the spice’s chemically diverse constituents that may synergistically contribute to its potential benefits.
Here’s a link to and citation for the paper,
The Essential Medicinal Chemistry of Curcumin by Kathryn M. Nelson, Jayme L. Dahlin, Jonathan Bisson, James Graham, Guido F. Pauli, and Michael A. Walters. J. Med. Chem., Article ASAP DOI: 10.1021/acs.jmedchem.6b00975 Publication Date (Web): January 11, 2017
It’s difficult to sum up Mostafa El-Sayed’s nearly 60-year career as a chemist in just a few sentences. He uses lasers and other tools to better understand the properties and behavior of molecules and the nanoscale world. He is a pioneer in the use of nanomedicine to fight cancer. He even has a spectroscopy rule named after him: the “El-Sayed rule.” For all of these reasons and more, El-Sayed received the Priestley Medal in 2016, the highest honor given by the American Chemical Society. His work is the focus of the latest episode of ACS’ Prized Science series, available here: https://youtu.be/Vm8OBZuy-Fk.
The American Chemical Society (ACS) has produced a video titled, “How that ‘old book smell’ could save priceless artifacts” according to their Sept. 6, 2016 news release on EurekAlert,
Odor-detecting devices like Breathalyzers have been used for years to determine blood-alcohol levels in drunk drivers. Now, researchers are using a similar method to sniff out the rate of decay in historic art and artifacts. By tracking the chemicals in “old book smell” and similar odors, conservators can react quickly to preserve priceless art and artifacts at the first signs of decay. In this Speaking of Chemistry, Sarah Everts explains how cultural-heritage science uses the chemistry of odors to save books, vintage jewelry and even early Legos. …
It was the 252nd meeting for the American Chemical Society from Aug. 21 – 25, 2016 and that meant a flurry of news about the latest research. From an Aug. 23, 2016 news item on Nanowerk,
Whether severe trauma occurs on the battlefield or the highway, saving lives often comes down to stopping the bleeding as quickly as possible. Many methods for controlling external bleeding exist, but at this point, only surgery can halt blood loss inside the body from injury to internal organs. Now, researchers have developed nanoparticles that congregate wherever injury occurs in the body to help it form blood clots, and they’ve validated these particles in test tubes and in vivo [animal testing].
The researchers will present their work today [Aug. 22, 2016] at the 252nd National Meeting & Exposition of the American Chemical Society (ACS). ACS, the world’s largest scientific society, is holding the meeting here through Thursday. It features more than 9,000 presentations on a wide range of science topics.
“When you have uncontrolled internal bleeding, that’s when these particles could really make a difference,” says Erin B. Lavik, Sc.D. “Compared to injuries that aren’t treated with the nanoparticles, we can cut bleeding time in half and reduce total blood loss.”
Trauma remains a top killer of children and younger adults, and doctors have few options for treating internal bleeding. To address this great need, Lavik’s team developed a nanoparticle that acts as a bridge, binding to activated platelets and helping them join together to form clots. To do this, the nanoparticle is decorated with a molecule that sticks to a glycoprotein found only on the activated platelets.
Initial studies suggested that the nanoparticles, delivered intravenously, helped keep rodents from bleeding out due to brain and spinal injury, Lavik says. But, she acknowledges, there was still one key question: “If you are a rodent, we can save your life, but will it be safe for humans?”
As a step toward assessing whether their approach would be safe in humans, they tested the immune response toward the particles in pig’s blood. If a treatment triggers an immune response, it would indicate that the body is mounting a defense against the nanoparticle and that side effects are likely. The team added their nanoparticles to pig’s blood and watched for an uptick in complement, a key indicator of immune activation. The particles triggered complement in this experiment, so the researchers set out to engineer around the problem.
“We made a battery of particles with different charges and tested to see which ones didn’t have this immune-response effect,” Lavik explains. “The best ones had a neutral charge.” But neutral nanoparticles had their own problems. Without repulsive charge-charge interactions, the nanoparticles have a propensity to aggregate even before being injected. To fix this issue, the researchers tweaked their nanoparticle storage solution, adding a slippery polymer to keep the nanoparticles from sticking to each other.
Lavik also developed nanoparticles that are stable at higher temperatures, up to 50 degrees Celsius (122 degrees Fahrenheit). This would allow the particles to be stored in a hot ambulance or on a sweltering battlefield.
In future studies, the researchers will test whether the new particles activate complement in human blood. Lavik also plans to identify additional critical safety studies they can perform to move the research forward. For example, the team needs to be sure that the nanoparticles do not cause non-specific clotting, which could lead to a stroke. Lavik is hopeful though that they could develop a useful clinical product in the next five to 10 years.
It’s not unusual for scientists to give an estimate of 5 – 10 years before their science reaches the market. Another popular range is 3 – 5 years.
Adding eggshell nanoparticles to a bioplastic (shown above) increases the strength and flexibility of the material, potentially making it more attractive for use in the packaging industry. Credit: Vijaya Rangari/Tuskegee University
Eggshells are both marvels and afterthoughts. Placed on end, they are as strong as the arches supporting ancient Roman aqueducts. Yet they readily crack in the middle, and once that happens, we discard them without a second thought. But now scientists report that adding tiny shards of eggshell to bioplastic could create a first-of-its-kind biodegradable packaging material that bends but does not easily break.
The researchers present their work today [March 15, 2016] at the 251st National Meeting & Exposition of the American Chemical Society (ACS).
“We’re breaking eggshells down into their most minute components and then infusing them into a special blend of bioplastics that we have developed,” says Vijaya K. Rangari, Ph.D. “These nano-sized eggshell particles add strength to the material and make them far more flexible than other bioplastics on the market. We believe that these traits — along with its biodegradability in the soil — could make this eggshell bioplastic a very attractive alternative packaging material.”
Worldwide, manufacturers produce about 300 million tons of plastic annually. Almost 99 percent of it is made with crude oil and other fossil fuels. Once it is discarded, petroleum-based plastics can last for centuries without breaking down. If burned, these plastics release carbon dioxide into the atmosphere, which can contribute to global climate change.
As an alternative, some manufacturers are producing bioplastics — a form of plastic derived from cornstarch, sweet potatoes or other renewable plant-based sources — that readily decompose or biodegrade once they are in the ground. However, most of these materials lack the strength and flexibility needed to work well in the packaging industry. And that’s a problem since the vast majority of plastic is used to hold, wrap and encase products. So petroleum-based materials continue to dominate the market, particularly in grocery and other retail stores, where estimates suggest that up to a trillion plastic bags are distributed worldwide every year.
To find a solution, Rangari, graduate student Boniface Tiimob and colleagues at Tuskegee University experimented with various plastic polymers. Eventually, they latched onto a mixture of 70 percent polybutyrate adipate terephthalate (PBAT), a petroleum polymer, and 30 percent polylactic acid (PLA), a polymer derived from cornstarch. PBAT, unlike other oil-based plastic polymers, is designed to begin degrading as soon as three months after it is put into the soil.
This mixture had many of the traits that the researchers were looking for, but they wanted to further enhance the flexibility of the material. So they created nanoparticles made of eggshells. They chose eggshells, in part, because they are porous, lightweight and mainly composed of calcium carbonate, a natural compound that easily decays.
The shells were washed, ground up in polypropylene glycol and then exposed to ultrasonic waves that broke the shell fragments down into nanoparticles more than 350,000 times smaller than the diameter of a human hair. Then, in a laboratory study, they infused a small fraction of these particles, each shaped like a deck of cards, into the 70/30 mixture of PBAT and PLA. The researchers found that this addition made the mixture 700 percent more flexible than other bioplastic blends. They say this pliability could make it ideal for use in retail packaging, grocery bags and food containers — including egg cartons.
In addition to bioplastics, Rangari’s team is investigating using eggshell nanoparticles to enhance wound healing, bone regeneration and drug delivery.
Curators and conservators are acutely aware of how fragile artworks (see my Jan. 10, 2013 posting about a show where curators watched helplessly as daguerreotypes deteriorated) can be so this new technology from Disney is likely to excite a lot of interest. From a March 14, 2016 news item on phys.org,
Original drawings and sketches from Walt Disney Animation Studio’s more than 90-year history—from Steamboat Willie through Frozen—traveled internationally for the first time this summer. This gave conservators the rare opportunity to monitor the artwork with a new state-of-the-art sensor. A team of researchers report today that they developed and used a super-sensitive artificial “nose,” customized specifically to detect pollutants before they could irreversibly damage the artwork.
The researchers report on their preservation efforts at the 251st National Meeting & Exposition of the American Chemical Society (ACS). ACS, the world’s largest scientific society, is holding the meeting here through Thursday. It features more than 12,500 presentations on a wide range of science topics.
“Many pollutants that are problematic for human beings are also problematic for works of art,” says Kenneth Suslick, Ph.D. For example, pollutants can spur oxidative damage and acid degradation that, in prints or canvases, lead to color changes or decomposition. “The ability to monitor how much pollution a drawing or painting is exposed to is an important element of art preservation,” he says.
However, works of art are susceptible to damage at far lower pollutant levels than what’s considered acceptable for humans. “The high sensitivity of artists’ materials makes a lot of sense for two reasons,” explains Suslick, who is at the University of Illinois at Urbana-Champaign. “Human beings are capable of healing, which, of course, works of art cannot do. Moreover, human beings have finite lifetimes, whereas ideally works of art should last for future generations.”
To protect valuable works of art from these effects, conservators enclose vulnerable pieces in sealed display cases. But even then, some artists’ materials may “exhale” reactive compounds that accumulate in the cases and damage the art. To counter the accumulation of pollutants, conservators often hide sorbent materials inside display cases that scrub potentially damaging compounds from the enclosed environment. But it is difficult to know precisely when to replace the sorbents.
Suslick, a self-proclaimed “museum hound,” figured he might have an answer. He had already invented an optoelectronic nose — an array of dyes that change color when exposed to various compounds. But it is used largely for biomedical purposes, and it can’t sniff out the low concentrations of pollutants that damage works of art. To redesign the nose with the aim of protecting artwork, he approached scientists at the Getty Conservation Institute (GCI), a private non-profit institution in Los Angeles that works internationally to advance art conservation practice. He proposed that his team devise a sensor several hundred times more sensitive than existing devices used for cultural heritage research. The collaboration took off, and the scientists built a keener nose.
At the time, GCI was involved in a research project with the Walt Disney Animation Research Library to investigate the impact of storage environment on their animation cels, which are transparent sheets that artists drew or painted on before computer animation was developed. Such research ultimately could help extend the life of this important collection. The new sensors would monitor levels of acetic acid and other compounds that emanate from these sheets.
Before the exhibit, “Drawn from Life: The Art of Disney Animation Studios,” hit the road on tour, Suslick recommended placing the sensors in discrete places to monitor the pollution levels both inside and outside of the sealed and framed artworks. If the sensors indicated pollution levels inside the sealed frames were rising, conservators traveling with the Disney exhibit would know to replace the sorbents. An initial analysis of sensor data showed that the sorbents were effective. Suslick says he expects to continue expanding the sensors’ applications in the field of cultural heritage.
Collaborators in the project include Maria LaGasse, a graduate student in Suslick’s lab; Kristen McCormick, art exhibitions and conservation manager at the Walt Disney Animation Research Library; Herant Khanjian, assistant scientist; and Michael Schilling, senior scientist at the Getty Conservation Institute.
A German team that’s been working with sperm to develop a biological motor has announced it may have an alternative treatment for infertility, according to a Jan. 13, 2016 news item on Nanowerk,
Sperm that don’t swim well [also known as low motility] rank high among the main causes of infertility. To give these cells a boost, women trying to conceive can turn to artificial insemination or other assisted reproduction techniques, but success can be elusive. In an attempt to improve these odds, scientists have developed motorized “spermbots” that can deliver poor swimmers — that are otherwise healthy — to an egg. …
Artificial insemination is a relatively inexpensive and simple technique that involves introducing sperm to a woman’s uterus with a medical instrument. Overall, the success rate is on average under 30 percent, according to the Human Fertilisation & Embryology Authority of the United Kingdom. In vitro fertilization can be more effective, but it’s a complicated and expensive process. It requires removing eggs from a woman’s ovaries with a needle, fertilizing them outside the body and then transferring the embryos to her uterus or a surrogate’s a few days later. Each step comes with a risk for failure. Mariana Medina-Sánchez, Lukas Schwarz, Oliver G. Schmidt and colleagues from the Institute for Integrative Nanosciences at IFW Dresden in Germany wanted to see if they could come up with a better option than the existing methods.
Building on previous work on micromotors, the researchers constructed tiny metal helices just large enough to fit around the tail of a sperm. Their movements can be controlled by a rotating magnetic field. Lab testing showed that the motors can be directed to slip around a sperm cell, drive it to an egg for potential fertilization and then release it. The researchers say that although much more work needs to be done before their technique can reach clinical testing, the success of their initial demonstration is a promising start.
For those who prefer to watch their news, there’s this,
This team got a flurry of interest in 2014 when they first announced their research on using sperm as a biological motor. Tracy Staedter in a Jan. 15, 2014 article for Discovery.com describes their then results,
To create these tiny robots, the scientists first had to catch a few. First, they designed microtubes, which are essentially thin sheets of titanium and iron — which have a magnetic property — rolled into conical tubes, with one end wider than the other. Next, they put the microtubes into a solution in a Petri dish and added bovine sperm cells, which are similar size to human sperm. When a live sperm entered the wider end of the tube, it became trapped down near the narrow end. The scientists also closed the wider end, so the sperm wouldn’t swim out. And because sperm are so determined, the trapped cell pushed against the tube, moving it forward.
Next, the scientists used a magnetic field to guide the tube in the direction they wanted it to go, relying on the sperm for the propulsion.
The quick swimming spermbots could use controlled from outside a person body to deliver payloads of drugs and even sperm itself to parts of the body where its needed, whether that’s a cancer tumor or an egg.
This work isn’t nanotechnology per se but it has been published in ACS Nano Letters. Here’s a link to and a citation for the paper,