Tag Archives: American Chemical Society

The science of chocolate chip cookies

I’ve always thought baking and cooking have not been fully appreciated as applied science so it’s good to see the American Chemical Society (ACS) has addressed that shortsightedness, from a Sept. 26, 2015 ACS news release on EurekAlert,

Chocolate chip cookies are nearly universally adored. People like them in all sorts of textures, sizes and tastes. So how can you make your perfect cookie? Using science, of course. October 1 is National Homemade Cookies Day, so for this week’s Reactions episode, we partnered with Science News magazine’s Bethany Brookshire (@scicurious) to take a bite out of baking with the scientific method. …

We’re also celebrating the 10th anniversary of ACS ChemClubs. ChemClubs are high school clubs that provide students an opportunity to experience chemistry beyond the classroom. The ACS ChemClub program will be hosting a special live nationwide event on November 16 [2015] with the theme “Chemistry – Hacking Your Taste Buds.” For more information, visit http://www.acs.org/chemclub.

Here’s the video,


Nano-alchemy: silver nanoparticles that look like and act like gold

This work on ‘nano-alchemy’ comes out of the King Abduhllah University of Science and Technology (KAUST) according to a Sept. 22, 2015 article by Lisa Zynga for phys.org (Note: A link has been removed),

In an act of “nano-alchemy,” scientists have synthesized a silver (Ag) nanocluster that is virtually identical to a gold (Au) nanocluster. On the outside, the silver nanocluster has a golden yellow color, and on the inside, its chemical structure and properties also closely mimic those of its gold counterpart. The work shows that it may be possible to create silver nanoparticles that look and behave like gold despite underlying differences between the two elements, and could lead to creating similar analogues between other pairs of elements.

“In some aspects, this is very similar to alchemy, but we call it ‘nano-alchemy,'” Bakr [Osman Bakr, Associate Professor of Materials Science and Engineering at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia] told Phys.org. “When we first encountered the optical spectrum of the silver nanocluster, we thought that we may have inadvertently switched the chemical reagents for silver with gold, and ended up with gold nanoparticles instead. But repeated synthesis and measurements proved that the clusters were indeed silver and yet show properties akin to gold. It was really surprising to us as scientists to find not only similarities in the color and optical properties, but also the X-ray structure.”

In their study, the researchers performed tests demonstrating that the silver and gold nanoclusters have very similar optical properties. Typically, silver nanoclusters are brown or red in color, but this one looks just like gold because it emits light at almost the same wavelength (around 675 nm) as gold. The golden color can be explained by the fact that both nanoclusters have virtually identical crystal structures.

The question naturally arises: why are these silver and gold nanoclusters so similar, when individual atoms of silver and gold are very different, in terms of their optical and structural properties? As Bakr explained, the answer may have to do with the fact that, although larger in size, the nanoclusters behave like “superatoms” in the sense that their electrons orbit the entire nanocluster as if it were a single giant atom. These superatomic orbitals in the silver and gold nanoclusters are very similar, and, in general, an atom’s electron configuration contributes significantly to its properties.

Here’s one of the images used to illustrate Zynga’s article and the paper published by the American Chemical Society,

(Left) Optical properties of the silver and gold nanoclusters, with the inset showing photographs of the actual color of the synthesized nanoclusters. The graph shows the absorption (solid lines) and normalized emission (dotted lines) spectra. (Right) Various representations of the X-ray structure of the silver nanocluster. Credit: Joshi, et al. ©2015 American Chemical Society

(Left) Optical properties of the silver and gold nanoclusters, with the inset showing photographs of the actual color of the synthesized nanoclusters. The graph shows the absorption (solid lines) and normalized emission (dotted lines) spectra. (Right) Various representations of the X-ray structure of the silver nanocluster. Credit: Joshi, et al. ©2015 American Chemical Society

I encourage you to read Zynga’s article in its entirety. For the more technically inclined, here’s a link to and a citation for the researchers’ paper,

[Ag25(SR)18]: The “Golden” Silver Nanoparticle by Chakra P. Joshi, Megalamane S. Bootharaju, Mohammad J. Alhilaly, and Osman M. Bakr.J. Am. Chem. Soc., 2015, 137 (36), pp 11578–11581 DOI: 10.1021/jacs.5b07088 Publication Date (Web): August 31, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

Did the Fantastic Four (comic book heroes) get their powers from radiation?

The American Chemical Society (ACS) has gone old school regarding how the Fantastic Four comic book characters got their powers, radiation. (The latest movie version offers an alternate explanation.)

Here’s more about radiation and the possibility of developing super powers as a consequence of exposure from the ACS video podcast series, Reactions,

From the Aug. 4, 2015 ACS news release on EurekAlert,

The Thing, Human Torch, Invisible Woman and Mister Fantastic are back this summer! In the new movie reboot, the team gets its powers while in an alternate dimension. Here at Reactions, though, we stick to comic-book canon. In this week’s video, we explain the original way the Fantastic Four got their power – radiation – with help from SciPop Talks. Check it out here: https://youtu.be/GbmSmgTIQ8s.

That’s all, folks!

Carbon nanotubes as sensors in the body

Rachel Ehrenberg has written an Aug. 21, 2015 news item about the latest and greatest carbon nanotube-based biomedical sensors for the journal Nature,

The future of medical sensors may be going down the tubes. Chemists are developing tiny devices made from carbon nanotubes wrapped with polymers to detect biologically important compounds such as insulin, nitric oxide and the blood-clotting protein fibrinogen. The hope is that these sensors could simplify and automate diagnostic tests.

Preliminary experiments in mice, reported by scientists at a meeting of the American Chemical Society in Boston, Massachusetts, this week [Aug. 16 – 20, 2015], suggest that the devices are safe to introduce into the bloodstream or implant under the skin. Researchers also presented data showing that the nanotube–polymer complexes could measure levels of large molecules, a feat that has been difficult for existing technologies.

Ehrenberg focuses on one laboratory in particular (Note: Links have been removed),

“Anything the body makes, it is meant to degrade,” says chemical engineer Michael Strano, whose lab at the Massachusetts Institute of Technology (MIT) in Cambridge is behind much of the latest work1. “Our vision is to make a sensing platform that can monitor a whole range of molecules, and do it in the long term.”

To design one sensor, MIT  researchers coated nanotubes with a mix of polymers and nucleotides and screened for configurations that would bind to the protein fibrinogen. This large molecule is important for building blood clots; its concentration can indicate bleeding disorders, liver disease or impending cardiovascular trouble. The team recently hit on a material that worked — a first for such a large molecule, according to MIT nanotechnology specialist Gili Bisker. Bisker said at the chemistry meeting that the fibrinogen-detecting nanotubes could be used to measure levels of the protein in blood samples, or implanted in body tissue to detect changing fibrinogen levels that might indicate a clot.

The MIT team has also developed2 a sensor that can be inserted beneath the skin to monitor glucose or insulin levels in real time, Bisker reported. The team imagines putting a small patch that contains a wireless device on the skin just above the embedded sensor. The patch would shine light on the sensor and measure its fluorescence, then transmit that data to a mobile phone for real-time monitoring.

Another version of the sensor, developed3 at MIT by biomedical engineer Nicole Iverson and colleagues, detects nitric oxide. This signalling molecule typically indicates inflammation and is associated with many cancer cells. When embedded in a hydrogel matrix, the sensor kept working in mice for more than 400 days and caused no local inflammation, MIT chemical engineer Michael Lee reported. The nitric oxide sensors also performed well when injected into the bloodstreams of mice, successfully passing through small capillaries in the lungs, which are an area of concern for nanotube toxicity. …

There’s at least one corporate laboratory (Google X), working on biosensors although their focus is a little different. From a Jan. 9, 2015 article by Brian Womack and Anna Edney for BloombergBusiness,

Google Inc. sent employees with ties to its secretive X research group to meet with U.S. regulators who oversee medical devices, raising the possibility of a new product that may involve biosensors from the unit that developed computerized glasses.

The meeting included at least four Google workers, some of whom have connections with Google X — and have done research on sensors, including contact lenses that help wearers monitor their biological data. Google staff met with those at the Food and Drug Administration who regulate eye devices and diagnostics for heart conditions, according to the agency’s public calendar. [emphasis mine]

This approach from Google is considered noninvasive,

“There is actually one interface on the surface of the body that can literally provide us with a window of what happens inside, and that’s the surface of the eye,” Parviz [Babak Parviz, … was involved in the Google Glass project and has talked about putting displays on contact lenses, including lenses that monitor wearer’s health]  said in a video posted on YouTube. “It’s a very interesting chemical interface.”

Of course, the assumption is that all this monitoring is going to result in  healthier people but I can’t help thinking about an old saying ‘a little knowledge can be a dangerous thing’. For example, we lived in a world where bacteria roamed free and then we learned how to make them visible, determined they were disease-causing, and began campaigns for killing them off. Now, it turns out that at least some bacteria are good for us and, moreover, we’ve created other, more dangerous bacteria that are drug-resistant. Based on the bacteria example, is it possible that with these biosensors we will observe new phenomena and make similar mistakes?

The science of the Avengers: Age of Ultron

The American Chemical Society (ACS) has produced a video (almost 4 mins.) in their Reactions Science Video Series of podcasts focusing on the Avengers, super heroes, as portrayed in Avengers: Age of Ultron and science. From an April 29, 2015 ACS news release on EurekAlert,

Science fans, assemble! On May 1, the world’s top superhero team is back to save the day in “Avengers: Age of Ultron.” This week, Reactions looks at the chemistry behind these iconic heroes’ gear and superpowers, including Tony Stark’s suit, Captain America’s shield and more.

Here’s the video,

While the chemists are interested in the metal alloys, there is more ‘super hero science’ writing out there. Given my interests, I found the ‘Captain America’s shield as supercapacitor theory’ as described in Matt Shipman’s April 15, 2014 post on The Abstract (North Carolina State University’s official newsroom blog quite interesting. I featured Shipman’s ‘super hero and science’ series of posts in my April 28, 2014 posting.

Reversing Parkinson’s type symptoms in rats

Indian scientists have developed a technique for delivering drugs that could reverse Parkinson-like symptoms according to an April 22, 2015 news item on Nanowerk (Note: A link has been removed),

As baby boomers age, the number of people diagnosed with Parkinson’s disease is expected to increase. Patients who develop this disease usually start experiencing symptoms around age 60 or older. Currently, there’s no cure, but scientists are reporting a novel approach that reversed Parkinson’s-like symptoms in rats.

Their results, published in the journal ACS Nano (“Trans-Blood Brain Barrier Delivery of Dopamine-Loaded Nanoparticles Reverses Functional Deficits in Parkinsonian Rats”), could one day lead to a new therapy for human patients.

An April 22, 2015 American Chemical Society press pac news release (also on EurekAlert), which originated the news item, describes the problem the researchers were solving (Note: Links have been removed),

Rajnish Kumar Chaturvedi, Kavita Seth, Kailash Chand Gupta and colleagues from the CSIR-Indian Institute of Toxicology Research note that among other issues, people with Parkinson’s lack dopamine in the brain. Dopamine is a chemical messenger that helps nerve cells communicate with each other and is involved in normal body movements. Reduced levels cause the shaking and mobility problems associated with Parkinson’s. Symptoms can be relieved in animal models of the disease by infusing the compound into their brains. But researchers haven’t yet figured out how to safely deliver dopamine directly to the human brain, which is protected by something called the blood-brain barrier that keeps out pathogens, as well as many medicines. Chaturvedi and Gupta’s team wanted to find a way to overcome this challenge.

The researchers packaged dopamine in biodegradable nanoparticles that have been used to deliver other therapeutic drugs to the brain. The resulting nanoparticles successfully crossed the blood-brain barrier in rats, released its dopamine payload over several days and reversed the rodents’ movement problems without causing side effects.

The authors acknowledge funding from the Indian Department of Science and Technology as Woman Scientist and Ramanna Fellow Grant, and the Council of Scientific and Industrial Research (India).

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

Trans-Blood Brain Barrier Delivery of Dopamine-Loaded Nanoparticles Reverses Functional Deficits in Parkinsonian Rats by Richa Pahuja, Kavita Seth, Anshi Shukla, Rajendra Kumar Shukla, Priyanka Bhatnagar, Lalit Kumar Singh Chauhan, Prem Narain Saxena, Jharna Arun, Bhushan Pradosh Chaudhari, Devendra Kumar Patel, Sheelendra Pratap Singh, Rakesh Shukla, Vinay Kumar Khanna, Pradeep Kumar, Rajnish Kumar Chaturvedi, and Kailash Chand Gupta. ACS Nano, Article ASAP DOI: 10.1021/nn506408v Publication Date (Web): March 31, 2015
Copyright © 2015 American Chemical Society

This paper is open access.

Another recent example of breaching the blood-brain barrier, coincidentally, in rats, can be found in my Dec. 24, 2014 titled: Gelatin nanoparticles for drug delivery after a stroke. Scientists are also trying to figure out the the blood-brain barrier operates in the first place as per this April 22, 2015 University of Pennsylvania news release on EurekAlert titled, Penn Vet, Montreal and McGill researchers show how blood-brain barrier is maintained (University of Pennsylvania School of Veterinary Medicine, University of Montreal or Université de Montréal, and McGill University). You can find out more about CSIR-Indian Institute of Toxicology Research here.

Crumpling graphene to create a 3D structure and reflattening it afterwards

The reseaarchers at the University of Illinois College of Engineering are quite excited about a new technique for crumpling graphene as a Feb. 17, 2015 news item on ScienceDaily reports,

Researchers at the University of Illinois at Urbana-Champaign have developed a unique single-step process to achieve three-dimensional (3D) texturing of graphene and graphite. Using a commercially available thermally activated shape-memory polymer substrate, this 3D texturing, or “crumpling,” allows for increased surface area and opens the doors to expanded capabilities for electronics and biomaterials.

“Fundamentally, intrinsic strains on crumpled graphene could allow modulation of electrical and optical properties of graphene,” explained SungWoo Nam, an assistant professor of mechanical science and engineering at Illinois. “We believe that the crumpled graphene surfaces can be used as higher surface area electrodes for battery and supercapacitor applications. As a coating layer, 3D textured/crumpled nano-topographies could allow omniphobic/anti-bacterial surfaces for advanced coating applications.”

A Feb. 16, 2015 University of Illinois College of Engineering news release (also on EurekAlert), which originated the news item, describes the nature of graphene and what makes this technique so exciting,

Graphene—a single atomic layer of sp2-bonded carbon atoms—has been a material of intensive research and interest over recent years.  A combination of exceptional mechanical properties, high carrier mobility, thermal conductivity, and chemical inertness, make graphene a prime candidate material for next generation optoelectronic, electromechanical, and biomedical applications.

“In this study, we developed a novel method for controlled crumpling of graphene and graphite via heat-induced contractile deformation of the underlying substrate,” explained Michael Cai Wang, a graduate student and first author of the paper, “Heterogeneous, Three-Dimensional Texturing of Graphene,” which appeared in the journal Nano Letters. ”While graphene intrinsically exhibits tiny ripples in ambient conditions, we created large and tunable crumpled textures in a tailored and scalable fashion.”

“As a simpler, more scalable, and spatially selective method, this texturing of graphene and graphite exploits the thermally induced transformation of shape-memory thermoplastics, which has been previously applied to microfluidic device fabrication, metallic  film patterning, nanowire assembly, and robotic self-assembly applications,” added Nam, whose group has filed a patent for their novel strategy. “The thermoplastic nature of the polymeric substrate also allows for the crumpled graphene morphology to be arbitrarily re-flattened at the same elevated temperature for the crumpling process.”

“Due to the extremely low cost and ease of processing of our approach, we believe that this will be a new way to manufacture nanoscale topographies for graphene and many other 2D and thin-film materials.”

The researchers are also investigating the textured graphene surfaces for 3D sensor applications.

“Enhanced surface area will allow even more sensitive and intimate interactions with biological systems, leading to high sensitivity devices,” Nam said.

The funding agencies for this project were unexpectedly interesting (to me), from the news release,

Funding for this research was provided through the Air Force Office for Scientific Research, American Chemical Society and Brain Research Foundation. [emphasis mine] In addition to Wang, co-authors from Nam’s research group at Illinois include SungGyu Chun, Ryan Han, Ali Ashraf, and Pilgyu Kang.

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

Heterogeneous, Three-Dimensional Texturing of Graphene by Michael Cai Wang, SungGyu Chun, Ryan Steven Han, Ali Ashraf, Pilgyu Kang, and SungWoo Nam. Nano Lett., Article ASAP
DOI: 10.1021/nl504612y Publication Date (Web): February 10, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

Dexter Johnson has written a Feb. 20, 2015 post highlighting this work on his Nanoclast blog (on the Institute of Electrical and Electronics Engineers [IEEE] website).

A new approach to heating: warm the clothing not the room

A Jan. 7, 2015 news item on ScienceDaily describes a new type of textile which could change the way we use heat (energy),

To stay warm when temperatures drop outside, we heat our indoor spaces — even when no one is in them. But scientists have now developed a novel nanowire coating for clothes that can both generate heat and trap the heat from our bodies better than regular clothes. They report on their technology, which could help us reduce our reliance on conventional energy sources, in the ACS journal Nano Letters.

A Jan. 7, 2015 American Chemical Society (ACS) news release (also on EurekAlert), which originated the news item, provides more information about energy consumption and the researchers’ proposed solution,

Yi Cui [Stanford University] and colleagues note that nearly half of global energy consumption goes toward heating buildings and homes. But this comfort comes with a considerable environmental cost – it’s responsible for up to a third of the world’s total greenhouse gas emissions. Scientists and policymakers have tried to reduce the impact of indoor heating by improving insulation and construction materials to keep fuel-generated warmth inside. Cui’s team wanted to take a different approach and focus on people rather than spaces.

The researchers developed lightweight, breathable mesh materials that are flexible enough to coat normal clothes. When compared to regular clothing material, the special nanowire cloth trapped body heat far more effectively. Because the coatings are made out of conductive materials, they can also be actively warmed with an electricity source to further crank up the heat. The researchers calculated that their thermal textiles could save about 1,000 kilowatt hours per person every year — that’s about how much electricity an average U.S. home consumes in one month.

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

Personal Thermal Management by Metallic Nanowire-Coated Textile by Po-Chun Hsu, Xiaoge Liu, Chong Liu, Xing Xie, Hye Ryoung Lee, Alex J. Welch, Tom Zhao, and Yi Cui. Nano Lett., Article ASAP DOI: 10.1021/nl5036572 Publication Date (Web): November 30, 2014
Copyright © 2014 American Chemical Society

This paper is behind a paywall.