Tag Archives: Peng Wang

You mean Fitbit makes mistakes? More accuracy with ‘drawn-on-skin’ electronics

A July 30, 2020 news item on ScienceDaily announces news about more accurate health monitoring with electronics applied directly to your skin,

A team of researchers led by Cunjiang Yu, Bill D. Cook Associate Professor of Mechanical Engineering at the University of Houston, has developed a new form of electronics known as “drawn-on-skin electronics,” allowing multifunctional sensors and circuits to be drawn on the skin with an ink pen.

The advance, the researchers report in Nature Communications, allows for the collection of more precise, motion artifact-free health data, solving the long-standing problem of collecting precise biological data through a wearable device when the subject is in motion.

The imprecision may not be important when your FitBit registers 4,000 steps instead of 4,200, but sensors designed to check heart function, temperature and other physical signals must be accurate if they are to be used for diagnostics and treatment.

A July 30, 2020 University of Houston news release (also on EurekAlert) by Jeannie Kever, which originated the news item, goes on to explain why you might want to have electronics ‘drawn on your skin’,

The drawn-on-skin electronics are able to seamlessly collect data, regardless of the wearer’s movements.  

They also offer other advantages, including simple fabrication techniques that don’t require dedicated equipment.

“It is applied like you would use a pen to write on a piece of paper,” said Yu. “We prepare several electronic materials and then use pens to dispense them. Coming out, it is liquid. But like ink on paper, it dries very quickly.”

Wearable bioelectronics – in the form of soft, flexible patches attached to the skin – have become an important way to monitor, prevent and treat illness and injury by tracking physiological information from the wearer. But even the most flexible wearables are limited by motion artifacts, or the difficulty that arises in collecting data when the sensor doesn’t move precisely with the skin.

The drawn-on-skin electronics can be customized to collect different types of information, and Yu said it is expected to be especially useful in situations where it’s not possible to access sophisticated equipment, including on a battleground.

The electronics are able to track muscle signals, heart rate, temperature and skin hydration, among other physical data, he said. The researchers also reported that the drawn-on-skin electronics have demonstrated the ability to accelerate healing of wounds.

In addition to Yu, researchers involved in the project include Faheem Ershad, Anish Thukral, Phillip Comeaux, Yuntao Lu, Hyunseok Shim, Kyoseung Sim, Nam-In Kim, Zhoulyu Rao, Ross Guevara, Luis Contreras, Fengjiao Pan, Yongcao Zhang, Ying-Shi Guan, Pinyi Yang, Xu Wang and Peng Wang, all from the University of Houston, and Jiping Yue and Xiaoyang Wu from the University of Chicago.

The drawn-on-skin electronics are actually comprised of three inks, serving as a conductor, semiconductor and dielectric.

“Electronic inks, including conductors, semiconductors, and dielectrics, are drawn on-demand in a freeform manner to develop devices, such as transistors, strain sensors, temperature sensors, heaters, skin hydration sensors, and electrophysiological sensors,” the researchers wrote.

This research is supported by the Office of Naval Research and National Institutes of Health.

Caption: A new form of electronics known as “drawn-on-skin electronics” allows multifunctional sensors and circuits to be drawn on the skin with an ink pen. Credit: University of Houston

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

Ultra-conformal drawn-on-skin electronics for multifunctional motion artifact-free sensing and point-of-care treatment by Faheem Ershad, Anish Thukral, Jiping Yue, Phillip Comeaux, Yuntao Lu, Hyunseok Shim, Kyoseung Sim, Nam-In Kim, Zhoulyu Rao, Ross Guevara, Luis Contreras, Fengjiao Pan, Yongcao Zhang, Ying-Shi Guan, Pinyi Yang, Xu Wang, Peng Wang, Xiaoyang Wu & Cunjiang Yu. Nature Communications volume 11, Article number: 3823 (2020) DOI: https://doi.org/10.1038/s41467-020-17619-1

This paper is open access.

Bristly hybrid materials

Caption: [Image 1] A carbon fiber covered with a spiky forest of NiCoHC nanowires. Credit: All images reproduced from reference 1 under a Creative Commons Attribution 4.0 International License© 2018 KAUST

It makes me think of small, cuddly things like cats and dogs but it’s not. From an August 7, 2018 King Abdullah University of Science and Technology (KAUST; Saudi Arabia) news release (also published on August 12, 2018 on EurekAlert),

By combining multiple nanomaterials into a single structure, scientists can create hybrid materials that incorporate the best properties of each component and outperform any single substance. A controlled method for making triple-layered hollow nanostructures has now been developed at KAUST. The hybrid structures consist of a conductive organic core sandwiched between layers of electrocatalytically active metals: their potential uses range from better battery electrodes to renewable fuel production.

Although several methods exist to create two-layer materials, making three-layered structures has proven much more difficult, says Peng Wang from the Water Desalination and Reuse Center who co-led the current research with Professor Yu Han, member of the Advanced Membranes and Porous Materials Center at KAUST. The researchers developed a new, dual-template approach, explains Sifei Zhuo, a postdoctoral member of Wang’s team.

The researchers grew their hybrid nanomaterial directly on carbon paper–a mat of electrically conductive carbon fibers. They first produced a bristling forest of nickel cobalt hydroxyl carbonate (NiCoHC) nanowires onto the surface of each carbon fiber (image 1). Each tiny inorganic bristle was coated with an organic layer called hydrogen substituted graphdiyne (HsGDY) (image 2 [not included here]).

Next was the key dual-template step. When the team added a chemical mixture that reacts with the inner NiCoHC, the HsGDY acted as a partial barrier. Some nickel and cobalt ions from the inner layer diffused outward, where they reacted with thiomolybdate from the surrounding solution to form the outer nickel-, cobalt-co-doped MoS2 (Ni,Co-MoS2) layer. Meanwhile, some sulfur ions from the added chemicals diffused inwards to react with the remaining nickel and cobalt. The resulting substance (image 3 [not included here]) had the structure Co9S8, Ni3S2@HsGDY@Ni,Co-MoS2, in which the conductive organic HsGDY layer is sandwiched between two inorganic layers (image 4 [not included here]).

The triple layer material showed good performance at electrocatalytically breaking up water molecules to generate hydrogen, a potential renewable fuel. The researchers also created other triple-layer materials using the dual-template approach

“These triple-layered nanostructures hold great potential in energy conversion and storage,” says Zhuo. “We believe it could be extended to serve as a promising electrode in many electrochemical applications, such as in supercapacitors and sodium-/lithium-ion batteries, and for use in water desalination.”

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

Dual-template engineering of triple-layered nanoarray electrode of metal chalcogenides sandwiched with hydrogen-substituted graphdiyne by Sifei Zhuo, Yusuf Shi, Lingmei Liu, Renyuan Li, Le Shi, Dalaver H. Anjum, Yu Han, & Peng Wang. Nature Communicationsvolume 9, Article number: 3132 (2018) DOI: https://doi.org/10.1038/s41467-018-05474-0 Published 07 August 2018

This paper is open access.

 

Combining bacteriorhodopsin with semiconducting nanoparticles to generate hydrogen

Scientists at the US Argonne National Laboratory have created a hybrid bio-assisted photocatalyst according to a July 19, 2013 news item on ScienceDaily,

A protein found in the membranes of ancient microorganisms that live in desert salt flats could offer a new way of using sunlight to generate environmentally friendly hydrogen fuel, according to a new study by researchers at the U.S. Department of Energy’s Argonne National Laboratory.

Argonne nanoscientist Elena Rozhkova and her colleagues combined a pigment called bacteriorhodopsin with semiconducting nanoparticles to create a system that uses light to spark a catalytic process that creates hydrogen fuel.

Before getting to the new hybrid the story starts with nano titanium dioxide (from the July 16, 2013 Argonne National Laboratory press release, which originated the news item),

Scientists have been aware of the potential of titanium dioxide nanoparticles for light-based reactions since the early 1970s, when Japanese researchers discovered that a titanium dioxide electrode exposed to bright ultraviolet light could split water molecules in a phenomenon that came to be known as the Honda-Fujishima effect. Since then, scientists have made continuous efforts to extend the light reactivity of titanium dioxide photocatalysts into the visible part of the spectrum. The promise of these photocatalysts prompted scientists to experiment with different modifications to their basic chemistry in hope of making the reaction more efficient, Rozhkova said.

“Titanium dioxide alone reacts with ultraviolet light, but not with visible light, so we used biological photoreactive molecules as a building block to create a hybrid system that could use visible light efficiently,” Rozhkova said.

Rozhkova and her colleagues turned to bacteriorhodopsin – which is responsible for the unusual purple color of a number of salt flats in California and Nevada – because it uses sunlight as an energy source that allows it to act as a “proton pump.”  Proton pumps are proteins that typically straddle a cellular membrane and transfer protons from inside the cell to the extracellular space.

Here’s an image of the purple membrane caused by bacteriorhodopsin (from University of Bari [Italy] Professor Angela Correlli’s webpage of Photorecptors and Olfactory Receptors,

Bacteriorhodopsin is the only protein of purple membranes, which contains few different lipids. [downloaded from the University of Bari: http://www.biologia.uniba.it/fisiologia/corcelli/en/ric2.html]

Bacteriorhodopsin is the only protein of purple membranes, which contains few different lipids. [downloaded from the University of Bari: http://www.biologia.uniba.it/fisiologia/corcelli/en/ric2.html]

The press release goes on to describe the hybrid system,

In the Argonne system, the protons provided by the bacteriorhodopsin are combined with free electrons at small platinum sites interspersed in the titanium dioxide matrix. “The platinum nanoparticles are essential for creating a distinct spot for the production of the hydrogen molecule,” said Peng Wang, an Argonne postdoctoral researcher in Rozhkova’s group at Argonne’s Center for Nanoscale Materials.

“It is interesting that in biology, bacteriorhodopsin does not naturally participate in these kind of reactions,” Rozhkova said. “Its natural function really doesn’t have much to do at all with creating hydrogen. But as part of this hybrid, it helps make hydrogen under white light and at environmentally friendly conditions.”

This bio-assisted hybrid photocatalyst outperforms many other similar systems in hydrogen generation and could be a good candidate for fabrication of green energy devices that consume virtually infinite sources — salt water and sunlight.

You can find the published paper with the link below,

High-Performance Bioassisted Nanophotocatalyst for Hydrogen Production by Shankar Balasubramanian, Peng Wang, Richard D. Schaller, Tijana Rajh, and Elena A. Rozhkova. Nano Lett., 2013, 13 (7), pp 3365–3371 DOI: 10.1021/nl4016655 Publication Date (Web): June 19, 2013
Copyright © 2013 American Chemical Society

The paper is behind a paywall.

*The head for this posting was corrected from Combining bacteriorhodopsin with semiconduction nanopartcles to generate hydrogen to Combining bacteriorhodopsin with semiconductor nanoparticles to generate hydrogen on July 22, 2013 at 3:03 pm PDT.

** I changed the head for this posting again from ‘semiconductor’ to ‘semiconducting’ on July 23, 2013 at 6:50 am PDT.