A paper from the Pinkhassik Group was featured on the cover of Chemical Communications. Drs. Sergey Dergunov and Eugene Pinkhassik -- working with collaborators from Saint Louis University -- uncovered evidence for freely diffusing ground-state atomic oxygen, an elusive species whose existence in solution was proposed by never proven. This study used hollow porous nanocapsules developed in the Pinkhassik Group to physically separate the donor and acceptor of an oxygen atom. Photochemical reactions in the presence of a nanometer-thin porous barrier ruled out direct oxygen atom transfer mechanisms and, for the first time, confirmed the formation of diffusing atomic oxygen. Previously produced in the gas phase, atomic oxygen is an extraordinary reactive oxygen species; it is highly reactive like hydroxyl radical, yet selective like singlet oxygen or ozone. Evidence for atomic oxygen in solution provides new insights into the mechanisms of many oxidation reactions, facilitates the search for synthetically viable sources of atomic oxygen, and lays the groundwork for studying the controlled release of small oxidants from photoactivatable precursors.
With sadness I must report news about one of our colleagues.
Emeritus Professor Ulrich T. Mueller-Westerhoff, Ph.D., passed away after a brief illness on January 30, 2019 in Storrs, CT. He was born in Wuppertal, Germany, and grew up in Austria and Germany. After studies in chemistry at the Universities in Marburg and Munich, he received his Ph.D. from the University of Darmstadt in 1967. A postdoctoral stay at the University of California at Berkeley where he firstly synthesized uranocene was followed by employment at the IBM Research Station in Almaden, California. He transitioned back to academia when he moved to the University of Connecticut as Head of the Department of Chemistry in 1982. He was a Guest Professor at the University of Bern, University of Würzburg, and the Max-Planck Institute for Polymer Research. He was awarded an Alexander-von-Humboldt Foundation Senior US Scientist Award. He achieved emeritus status at UConn in 2002.
His research field in organometallic chemistry encompassed theoretical aspects of the bonding in sandwich complexes, the chemistry of metallocenophanes, and the utilization of metallodithiolenes. He prepared the last nickel metallodithiolene complex as a laser dye in the emeritus lab in 2017. In support of undergraduate research activities in chemistry, Ulli established the Mueller-Westerhoff Scholarship fund at the University of Connecticut, and many undergraduates have been, and continue to be, supported throughout the summers and the academic year. His sharp intellect, pointed opinions, and generous friendship will be missed.
Acrylics are an incredibly diverse and useful family of chemicals used in all kinds of products, from diapers to nail polish. Now, a team of researchers from UConn and ExxonMobil describe a new process for making them. The new method would increase energy efficiency and reduce toxic byproducts, they report in the Feb. 8 issue of Nature Communications.
The global market for acrylic acid is enormous. The world used close to 5 million metric tonnes of it in 2013, according to industry group PetroChemicals Europe. And no wonder, for acrylics and the closely related acrylates are the building blocks for many kinds of plastics, glues, textiles, dyes, paints, and papers. Strung together in long chains, they can make all kinds of useful materials. Acrylate mixed with sodium hydroxide, for example, makes a super absorbent material used in diapers. Add extra methyl groups (carbon plus three hydrogens), and acrylate makes plexiglass.
The current industrial process for making acrylics require high temperatures close to 450 F, and produce unwanted and sometimes harmful byproducts, such as ethylene, carbon dioxide, and hydrogen cyanide.
UConn chemistry Steve Suib, director of the University's Institute for Materials Science, and colleagues at UConn and ExxonMobil have designed a new way of making acrylics at mild temperatures. Their technique can be finely tuned to avoid producing unwanted chemicals.
"Scientists at ExxonMobil Research & Engineering partnering with professors Suib's group in UConn have been probing new technologies that can lower energy intensity, skip steps, improve energy efficiency, and reduce CO2 footprint in the production process of acrylics," says Partha Nandi, a chemist at ExxonMobil. "The recent publication in Nature Communications describes discovery of a new route to produce a class of acrylate derivatives in potentially fewer steps and with less energy"
The technique uses a porous catalyst made of manganese and oxygen. Catalysts are materials used to speed up reactions. Often, they provide a surface for the molecules to sit on while they react with each other, helping them to meet up in the right configurations to do the deed. In this case, the pores fill that role. The pores are 20 to 500 Angstroms wide, big enough for fairly large molecules to fit inside. The manganese atoms in the material can trade their electrons with nearby oxygens, which makes it easier for the right chemical reactions to happen. Depending on the starting ingredients, the catalyst can facilitate all different kinds of acrylics and acrylates, with very little waste, Suib says.
"We hope this can be scaled up," he says. "We want to maximize yield, minimize temperature, and make an even more active catalyst," that will help the reaction go faster. The group also found adding a little bit of lithium helped speed things up, too. They are currently studying the exact role of lithium, and experimenting with ways of improving the manganese and oxygen catalyst
This research was funded by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical, Biological, and Geological Sciences under grant DE-FG02-86ER13622.A000, as well as ExxonMobil
A new type of sensor could lead to artificial skin that someday helps burn victims ‘feel’ and safeguards the rest of us, University of Connecticut researchers suggest in a forthcoming paper in Advanced Materials.
Our skin’s ability to perceive pressure, heat, cold and vibration is a critical safety function that most people take for granted. But burn victims, those with prosthetic limbs, and others who have lost skin sensitivity for one reason or another, can’t take it for granted, and often injure themselves unintentionally.
Chemists Islam Mosa from UConn, and James Rusling from UConn and UConn Health, along with University of Toronto engineer Abdelsalam Ahmed, wanted to create a sensor that can mimic the sensing properties of skin. Such a sensor would need to be able to detect pressure, temperature and vibration. But perhaps it could do other things too, the researchers thought.
“It would be very cool if it had abilities human skin does not; for example, the ability to detect magnetic fields, sound waves, and abnormal behaviors,” said Mosa.
Mosa and his colleagues created such a sensor with a silicone tube wrapped in a copper wire and filled with a special fluid made of tiny particles of iron oxide just one billionth of a meter long, called nanoparticles. The nanoparticles rub around the inside of the silicone tube and create an electric current. The copper wire surrounding the silicone tube picks up the current as a signal. When this tube is bumped by something experiencing pressure, the nanoparticles move and the electric signal changes. Sound waves also create waves in the nanoparticle fluid, and the electric signal changes in a different way than when the tube is bumped.
The researchers found that magnetic fields alter the signal too, in a way distinct from pressure or sound waves. Even a person moving around while carrying the sensor changes the electrical current, and the team found they could distinguish between the electrical signals caused by walking, running, jumping, and swimming.
Metal skin might sound like a superhero power, but this skin wouldn’t make the wearer Colossus from the X-men. Rather, Mosa and his colleagues hope it could help burn victims “feel” again, and perhaps act as an early warning for workers exposed to dangerously high magnetic fields. Because the rubber exterior is completely sealed and waterproof, it could also serve as a wearable monitor to alert parents if their child fell into deep water in a pool, for example.
“The inspiration was to make something durable that would last for a very long time, and could detect multiple hazards,” Mosa says. The team has yet to test the sensor for its response to heat and cold, but they suspect it will work for those as well. The next step is to make the sensor in a flat configuration, more like skin, and see if it still works.
Among the authors of the paper are Esraa Elsanadidy and Mohamed Sharafeldin from UConn, and Islam Hassan from McMaster University and Prof. Shenqiang Ren from State University of New York at Buffalo. This work is supported by National Institute of Health (NIH), National Science Foundation (NSF) and US. Department of Energy.
On December 18, 2018, The Chronicle featured Kumar Group's NanoArt display at the Windham Regional Art Gallery. The front-page article, "Art at the Mall," highlighted the Jumar Group's display, as well as the work of other local artists. The NanoArt collection showcases colored electron microscope images that capture proteins in a new light. "The art aspects of this is nature's art. We're trying to connect the signs, and the art bridges that," says Kumar.
On Tuesday, December 4th, a product of a UConn Chemistry start-up will be launching into space on the SpaceX CRS-16! With the support of a 2016 MassChallenge CASIS/Boeing Award, a retinal implant developed by LambdaVision will be the subject of research conducted by the International Space Station (ISS) U.S. National Laboratory. As the ISS orbits the Earth, the retinal implant will be studied to examine the effects of microgravity in layer-by-layer manufacturing.
LambdaVision is the produce of the research group of Dr.Robert Birdge (Harold S. Schwnek Sr. Distinguished Chair Emeritus; Founder of LambdaVision), Dr. Nicole Wagner (Assistant Research Professor; CEO), and Dr. Jordan Greco (Assistant Research Professor; CSO)
Tuberculosis is a sneaky disease. The bacteria hide from antibiotics inside the very immune cells that are supposed to kill them, making treatment long and difficult. But in the November issue of ACS Infectious Diseases, UConn chemists report a new antibiotic that can find and kill tuberculosis bacteria where they hide.
Tuberculosis is the number one cause of death from infectious disease worldwide. About 25 percent of people on the planet are currently infected. Most of those infections will stay dormant, but one in 10 will become active, infectious, and often fatal if untreated.
Tuberculosis is caused by a bacteria called Mycobacterium tuberculosis. Because of Mycobacterium’s unique lifestyle, in which they allow themselves to be eaten by macrophage immune cells and then grow inside of them, they are very hard to treat. People infected with tuberculosis must typically take a cocktail of antibiotics diligently over many months, because the bacteria are only susceptible to the drugs when they break out of the macrophage in which they were born and search out a new one to invade.
UConn chemist Alfredo Angeles-Boza and his then-graduate student, Daben Libardo, and colleagues from the Indian Institute of Science, the Max Planck Institute, and MIT, decided to make an antibiotic that could make its way into the macrophages and hit the Mycobacteria where they hide. Angeles-Boza and Libardo had previously worked with antibiotics produced by fish, sea squirts, and other sea creatures. Many of these sea creatures make antibiotic peptides – small pieces of protein-like material – with a special chemical talent: when they bind to copper atoms, they enable the copper to shift its electrical charge from +2 to +3 and back. Copper with this ability becomes aggressive, ripping electrons away from some molecules and adding them to others, particularly oxygen-containing molecules. The oxygen-containing molecules become free radicals, dangerous chemicals that attack anything they encounter, including Mycobacteria.
Human macrophages infected with Mycobacteria also use copper to attack the bacteria, but they do so in a less sophisticated way. They trap the bacteria in a bubble and then inject copper +1 ions – that is, plain copper atoms with a plus one charge (Cu+) – into the bubble. But the Mycobacteria can handle that. To them, the bubble is a safe haven, and the Cu+ ions are mere annoyances. The bacteria can steal an extra electron from the Cu+ to make it Cu2+. The copper becomes unreactive and safe that way. And when enough Cu2+ surrounds the Mycobacteria, other, more dangerous kinds of copper can’t get close.
Surrounded by defanged copper, “the bacteria can grow in peace. It’s elegant!” says Angeles-Boza. But if Angeles-Boza and Libardo have their way, the copper camouflage will become Mycobacteria’s downfall. If the antibiotic peptides can get close to the bacteria, they can grab onto one of the copper ions and weaponize it. The trick is getting the peptide close to the bacteria.
To do that, the chemists put the peptides into little bubbles similar to the kind cells use to move around packets of protein ingredients and other tasty stuff. When the bacteria snags one for a snack, the peptide works its chemistry and kills it.
The antibiotic peptide developed by Libardo and Angeles Boza effectively kills Mycobacteria living in macrophages in the lab, but they haven’t been able to cure tuberculosis in mice yet – peptide drugs have various problems that make them tricky to use in mammals. The next step in the research is to use the same chemistry in smaller molecules that can be taken as pills like more typical antibiotics.
Dr. Yao Lin, Associate Professor of Chemistry/Polymer Program, and fellow collaborators were recently published in the Journal of the American Chemical Society. Below is a description of the research:
The control of reaching a specifically designed morphology in supramolecular assembly is one of the key aspects for future success in the area of supramolecular materials, As different structures can be formed by different pathways or by a temperature dependent polymorphism, novel strategies have to be established to obtain a desired structure in the resulting materials. Supported by an NSF CAREER grant and the “Research Opportunities in Europe for NSF CAREER Awardees,” Prof. Yao Lin got an opportunity to attack this challenge by working with Prof. Bert Meijer at the Eindhoven University of Technology. Together, they discovered that increased dynamics is required to provide enough flexibility of the system to form defect-free structures in water. Without this flexibility, the assemblies are frozen into a variety of structures that are very similar at the supramolecular level, but less defined at the mesoscopic level.
In the bottom drawer of your desk at home lie all the “must-haves” of yesteryear — a bundle of knotted earphones, a broken computer mouse, some overplayed CDs, a flip phone, an iPod. A study in The Global E-waste Monitor 2017 reported that in 2016 humans generated 44.7 million metric tons of electronic waste (e-waste). And in that graveyard of a desk drawer, the basement, or a landfill, all these devices will rot for hundreds, even thousands, of years before degrading. The glass used in just one cell phone takes some 500 years to decompose.
But what if the future smartphones and tablets were made of edible materials? To chemistry professor Challa Kumar, a future where you can pop your cell phone in a pot of water, swirl it around, bring it to a boil, and have yourself a yummy iPhone stew is not science fiction but a future reality of his research in bionanotechnology, or what he calls “edible chemistry.”
Kumar and his team of graduate students created a white LED light from bovine serum albumin (BSA), a waste product of the meat industry. White LEDs are used in electronics like phones and TVs that emit white light from their screens. Kumar’s “hamburger protein” LEDs emit white light at a higher resolution than current LEDs and, says Kumar, “When you are done with the device, you could eat it.”
“We are the only group in the world doing this where both products and reactants are edible — to humans, plants, or bacteria,” he adds.
The team’s research has clinical significance, too. The edible LED also has inexpensive pH and glucose sensing capabilities. Combined with the team’s food-based batteries, these LEDs could replace current electronic glucose meters for diabetics.
Kumar also is exploring the possibility of using lipids from coconut oil to replace the toxic elements in current cancer cell–targeting treatments. He and his students believe the uses for edible chemistry are limitless, that it is the future of technology as well as environmental awareness.
In the not-too-distant future, they say, we could be watching our favorite Netflix series on screens made from the same materials as last night’s burgers.
-Cara Williams ’18 (CLAS) courtesy of UConn Magazine
Prof. James Rusling, Postdoctoral Fellow Islam Mosa, and Graduate Student Esraa Elsanadidy are the recipients of a Fall 2018 Accelerate UConn Grant for their project “Biocap-Harvest.” This project involves harvesting energy using nanogenerators and storing it to create standalone power systems for implantable, wearable, and portable electronics. All winning teams receive special training and a $3,000 seed grant. Accelerate UConn is the University’s National Science Foundation Innovation Corps (I-Corps) site aiming to catalyze innovation and entrepreneurship.
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