Tag Archives: Yang Zhao

Nanoparticle drug delivery could reduce rejection rates for corneal transplants

I like pictures of happy researchers and, as these pictures go, the researchers seem pretty relaxed,

Caption: Qingguo Xu, D.Phil., associate professor of pharmaceutics and ophthalmology at VCU School of Pharmacy, (right) in the lab with Tuo Meng, Ph.D., (left) and Vineet Kulkarni. (School of Pharmacy) Credit: VCU School of Pharmacy

A March 23, 2023 Virginia Commonwealth University (VCU) news release (also on EurekAlert) announces work into making corneal transplants more successful, Note: A link has been removed,

Corneal transplants can be the last step to returning clear vision to many patients suffering from eye disease. Each year, approximately 80,000 corneal transplantations take place in the U.S. Worldwide, more than 184,000 corneal transplantation surgeries are performed annually. 

However, rejection rates for the corneal grafts can be as high as 10%. This is largely due to poor patient compliance to the medications, which require frequent administrations of topical eyedrops over a long period of time. 

This becomes especially acute when patients show signs of early rejection of the transplanted corneas. When this occurs, patients need to apply topical eyedrops [sic] hourly to rescue the corneal grafts from failure. 

The tedious process of eyedrop [sic] dosing causes a tremendous burden for patients. The resulting noncompliance to medication treatment can lead to even higher graft-rejection rates. 

Research led by a team at Virginia Commonwealth University may make the corneal grafts more successful by using nanoparticles to encapsulate the medication. The novel approach could significantly improve patient compliance, according to a paper recently published in Science Advances, “Six-month effective treatment of corneal graft rejection.”

Each nanoparticle encapsulates a drug called dexamethasone sodium phosphate, one of the most commonly used corticosteroids for various ocular diseases treatment such as ocular inflammation, non-infectious uveitis, macular edema and corneal neovascularization. By using the nanoparticles to control the release of the medicine over time, patients would require only one injection right after the corneal transplantation surgery without the frequent eye drops. Our studies have shown that using this method the medication maintains its efficacy for six months on a corneal graft rejection model. 

In addition, because the medicine is released slowly and directly where it is most needed, the approach requires much lower doses than current standard eyedrop treatment while providing better efficacy and safety profiles.

Qingguo Xu, D.Phil., the principal investigator of this project and an associate professor of pharmaceutics and ophthalmology at VCU School of Pharmacy, collaborated with Justin Hanes, Ph.D., the Lewis J. Ort professor of ophthalmology at Johns Hopkins University.

Xu said, “To improve patient compliance and treatment efficacy, we developed a tiny nanoparticle (around 200 nanometers) that in animal studies enables the release of the drug up to six months after a single subconjunctival injection along the eyeball.”

Tuo Meng, Ph.D., who worked on the project as a doctoral student at VCU and is the first author of this paper, said: “In our preclinical corneal graft rejection model, the single dosing of the nanoparticle successfully prevented corneal graft rejection for six months.” 

More importantly, the nanoparticle approach reversed signs of early rejection and maintained corneal grafts for six months without rejection. 

This work was supported by the National Eye Institute, National Institutes of Health, through the R01 grant R01EY027827. 

Xu’s lab focuses on developing nanotherapeutics for safer and more effective treatment of various eye diseases.

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

Six-month effective treatment of corneal graft rejection by Tuo Meng, Jinhua Zheng, Min Chen, Yang Zhao, Hadi Sudarjat, Aji Alex M.R., Vineet Kulkarni, Yumin Oh, Shiyu Xia, Zheng Ding, Hyounkoo Han, Nicole Anders, Michelle A. Rudek, Woon Chow, Walter Stark, Laura M. Ensign, Justin Hanes, and Qingguo Xu. Science Advances 22 Mar 2023 Vol 9, Issue 12 DOI: 10.1126/sciadv.adf4608

This paper is open access.

Humans with built-in night vision thanks to nanoparticles

In the world of video games such as the Deus Ex series eye augmentations are standard,now it seems that fantasy could become reality according to the latest American Chemical Society (ACS) meeting held in Fall 2019. From an August 27, 2019 news item on Nanowerk,

Movies featuring heroes with superpowers, such as flight, X-ray vision or extraordinary strength, are all the rage. But while these popular characters are mere flights of fancy, scientists have used nanoparticles to confer a real superpower on ordinary mice: the ability to see near-infrared light. Today, scientists report progress in making versions of these nanoparticles that could someday give built-in night vision to humans.

The researchers will present their results at the American Chemical Society (ACS) Fall 2019 National Meeting & Exposition.

“When we look at the universe, we see only visible light,” says Gang Han, Ph.D., the project’s principal investigator, who is presenting the work at the meeting. “But if we had near-infrared vision, we could see the universe in a whole new way. We might be able to do infrared astronomy with the naked eye, or have night vision without bulky equipment.”

An August 27, 2019 ACS news release, which originated the news item, explores the research about mammalian eyes (specifically mice) being presented in more depth,

The eyes of humans and other mammals can detect light between the wavelengths of 400 and 700 nanometers (nm). Near-infrared (NIR) light, on the other hand, has longer wavelengths — 750 nm to 1.4 micrometers. Thermal imaging cameras can help people see in the dark by detecting NIR radiation given off by organisms or objects, but these devices are typically bulky and inconvenient. Han and his colleagues wondered whether they could give mice NIR vision by injecting a special type of nanomaterial, called upconversion nanoparticles (UCNPs), into their eyes. These nanoparticles, which contain the rare-earth elements erbium and ytterbium, can convert low-energy photons from NIR light into higher-energy green light that mammalian eyes can see.

In work published earlier this year [2019], the researchers, who are at the University of Massachusetts Medical School, targeted UCNPs to photoreceptors in mouse eyes by attaching a protein that binds to a sugar molecule on the photoreceptor surface. Then, they injected the photoreceptor-binding UCNPs behind the retinas of the mice. To determine whether the injected mice could see and mentally process NIR light, the team conducted several physiological and behavioral tests. For example, in one test, the researchers placed the mice into a Y-shaped tank of water. One branch of the tank had a platform that the mice could climb on to escape the water. The researchers trained the mice to swim toward visible light in the shape of a triangle, which marked the escape route. A similarly lit circle marked the branch without a platform. Then, the researchers replaced the visible light with NIR light. “The mice with the particle injection could see the triangle clearly and swim to it each time, but the mice without the injection could not see or tell the difference between the two shapes,” says Han. A video of this work, posted by Han’s institution, can be viewed here.

Although the UCNPs persisted in the mice’s eyes for at least 10 weeks and did not cause any noticeable side effects, Han wants to improve the safety and sensitivity of the nanomaterials before he contemplates trying them out in humans. “The UCNPs in our published paper are inorganic, and there are some drawbacks there,” Han says. “The biocompatibility is not completely clear, and we need to improve the brightness of the nanoparticles for human use.” Now, the team is experimenting with UCNPs made up of two organic dyes, instead of rare-earth elements. “We’ve shown that we can make organic UCNPs with much improved brightness compared with the inorganic ones,” he says. These organic nanoparticles can emit either green or blue light. In addition to having improved properties, the organic dyes could also have fewer regulatory hurdles.

One of the next steps for the project might be translating the technology to man’s best friend. “If we had a super dog that could see NIR light, we could project a pattern onto a lawbreaker’s’ body from a distance, and the dog could catch them without disturbing other people,” Han says. Superhero powers aside, the technology could also have important medical applications, such as treating diseases of the eye. “We’re actually looking at how to use NIR light to release a drug from the UNCPs specifically at the photoreceptors,” Han says.

Here’s a link to and a citation for the paper mentioned in the ACS news release,

Mammalian Near-Infrared Image Vision through Injectable and Self-Powered Retinal Nanoantennae by Yuqian Ma, Jin Bao, Yuanwei Zhang, Zhanjun Li, Xiangyu Zhou. Changlin Wan, Ling Huang, Yang Zhao, Gang Han, Tian Xue. Cell Volume 177, ISSUE 2, P243-255.e15, April 04, 2019 DOI:https://doi.org/10.1016/j.cell.2019.01.038 First published online: February 28, 2019

This paper appears to be open access.

It’s going to be a while before this research makes it to human clinical trials, assuming it does. In the meantime, it seems that the plan is to continue research using dogs.

As you wait to find out how the researchers progress, you can check out my most recent mention of the Deus Ex video game series in a Sept. 1, 2016 posting about the latest entry to the series: Deus Ex: Mankind Divided.

Self-healing lithium-ion batteries for textiles

It’s easy to forget how hard we are on our textiles. We rip them, step on them, agitate them in water, splatter them with mud, and more. So, what happens when we integrate batteries and electronics into them? An Oct. 20, 2016 news item on phys.org describes one of the latest ‘textile batter technologies’,

Electronics that can be embedded in clothing are a growing trend. However, power sources remain a problem. In the journal Angewandte Chemie, scientists have now introduced thin, flexible, lithium ion batteries with self-healing properties that can be safely worn on the body. Even after completely breaking apart, the battery can grow back together without significant impact on its electrochemical properties.

wiley_selfhealinglithiumionbattery

© Wiley-VCH

An Oct. 20, 2016 Wiley Angewandte Chemie International Edition press release (also on EurekAlert), which originated the news item, describes some of the problems associated with lithium-ion batteries and this new technology designed to address them,

Existing lithium ion batteries for wearable electronics can be bent and rolled up without any problems, but can break when they are twisted too far or accidentally stepped on—which can happen often when being worn. This damage not only causes the battery to fail, it can also cause a safety problem: Flammable, toxic, or corrosive gases or liquids may leak out.

A team led by Yonggang Wang and Huisheng Peng has now developed a new family of lithium ion batteries that can overcome such accidents thanks to their amazing self-healing powers. In order for a complicated object like a battery to be made self-healing, all of its individual components must also be self-healing. The scientists from Fudan University (Shanghai, China), the Samsung Advanced Institute of Technology (South Korea), and the Samsung R&D Institute China, have now been able to accomplish this.

The electrodes in these batteries consist of layers of parallel carbon nanotubes. Between the layers, the scientists embedded the necessary lithium compounds in nanoparticle form (LiMn2O4 for one electrode, LiTi2(PO4)3 for the other). In contrast to conventional lithium ion batteries, the lithium compounds cannot leak out of the electrodes, either while in use or after a break. The thin layer electrodes are each fixed on a substrate of self-healing polymer. Between the electrodes is a novel, solvent-free electrolyte made from a cellulose-based gel with an aqueous lithium sulfate solution embedded in it. This gel electrolyte also serves as a separation layer between the electrodes.

After a break, it is only necessary to press the broken ends together for a few seconds for them to grow back together. Both the self-healing polymer and the carbon nanotubes “stick” back together perfectly. The parallel arrangement of the nanotubes allows them to come together much better than layers of disordered carbon nanotubes. The electrolyte also poses no problems. Whereas conventional electrolytes decompose immediately upon exposure to air, the new gel is stable. Free of organic solvents, it is neither flammable nor toxic, making it safe for this application.

The capacity and charging/discharging properties of a battery “armband” placed around a doll’s elbow were maintained, even after repeated break/self-healing cycles.

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

A Self-Healing Aqueous Lithium-Ion Battery by Yang Zhao, Ye Zhang, Hao Sun, Xiaoli Dong, Jingyu Cao, Lie Wang, Yifan Xu, Jing Ren, Yunil Hwang, Dr. In Hyuk Son, Dr. Xianliang Huang, Prof. Yonggang Wang, and Prof. Huisheng Peng. Angewandte Chemie International Edition DOI: 10.1002/anie.201607951 Version of Record online: 12 OCT 2016

© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

Shape memory in a supercapacitor fibre for ‘smart’ textiles (wearable tech: 1 of 3)

Wearable technology seems to be quite trendy for a grouping not usually seen: consumers, fashion designers, medical personnel, manufacturers, and scientists.

The first in this informal series concerns a fibre with memory shape. From a Nov. 19, 2015 news item on Nanowerk (Note: A link has been removed),

Wearing your mobile phone display on your jacket sleeve or an EKG probe in your sports kit are not off in some distant imagined future. Wearable “electronic textiles” are on the way. In the journal Angewandte Chemie (“A Shape-Memory Supercapacitor Fiber”), Chinese researchers have now introduced a new type of fiber-shaped supercapacitor for energy-storage textiles. Thanks to their shape memory, these textiles could potentially adapt to different body types: shapes formed by stretching and bending remain “frozen”, but can be returned to their original form or reshaped as desired.

A Nov. 19, 2015 Wiley Publishers press release, which originated the news item, provides context and detail about the work,

Any electronic components designed to be integrated into textiles must be stretchable and bendable. This is also true of the supercapacitors that are frequently used for data preservation in static storage systems (SRAM). SRAM is a type of storage that holds a small amount of data that is rapidly retrievable. It is often used for caches in processors or local storage on chips in devices whose data must be stored for long periods without a constant power supply. Some time ago, a team headed by Huisheng Peng at Fudan University developed stretchable, pliable fiber-shaped supercapacitors for integration into electronic textiles. Peng and his co-workers have now made further progress: supercapacitor fibers with shape memory.

Any electronic components designed to be integrated into textiles must be stretchable and bendable. This is also true of the supercapacitors that are frequently used for data preservation in static storage systems (SRAM). SRAM is a type of storage that holds a small amount of data that is rapidly retrievable. It is often used for caches in processors or local storage on chips in devices whose data must be stored for long periods without a constant power supply.
Some time ago, a team headed by Huisheng Peng at Fudan University developed stretchable, pliable fiber-shaped supercapacitors for integration into electronic textiles. Peng and his co-workers have now made further progress: supercapacitor fibers with shape memory.

The fibers are made using a core of polyurethane fiber with shape memory. This fiber is wrapped with a thin layer of parallel carbon nanotubes like a sheet of paper. This is followed by a coating of electrolyte gel, a second sheet of carbon nanotubes, and a final layer of electrolyte gel. The two layers of carbon nanotubes act as electrodes for the supercapacitor. Above a certain temperature, the fibers produced in this process can be bent as desired and stretched to twice their original length. The new shape can be “frozen” by cooling. Reheating allows the fibers to return to their original shape and size, after which they can be reshaped again. The electrochemical performance is fully maintained through all shape changes.

Weaving the fibers into tissues results in “smart” textiles that could be tailored to fit the bodies of different people. This could be used to make precisely fitted but reusable electronic monitoring systems for patients in hospitals, for example. The perfect fit should render them both more comfortable and more reliable.

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

A Shape-Memory Supercapacitor Fiber by Jue Deng, Ye Zhang, Yang Zhao, Peining Chen, Dr. Xunliang Cheng, & Prof. Dr. Huisheng Peng. Angewandte Chemie International Edition  DOI: 10.1002/anie.201508293  First published: 3 November 2015

This paper is behind a paywall.

Smart ‘curtains’ from the University of California at Berkeley

There’s a weirdly fascinating video that accompanies this research into light-activation and carbon nanotubes,

A Jan. 10, 2014 news item on Nanowerk provides an explanation,

A research team led by Ali Javey, associate professor of electrical engineering and computer sciences [University of California at Berkeley], layered carbon nanotubes – atom-thick rolls of carbon – onto a plastic polycarbonate membrane to create a material that moves quickly in response to light. Within fractions of a second, the nanotubes absorb light, convert it into heat and transfer the heat to the polycarbonate membrane’s surface. The plastic expands in response to the heat, while the nanotube layer does not, causing the two-layered material to bend.

The Jan. 9, 2014 University of California at Berkeley research brief by Sarah Yang, which originated the news item, provides some perspective from lead researcher Javey and a few more details about the research,

“The advantages of this new class of photo-reactive actuator is that it is very easy to make, and it is very sensitive to low-intensity light,” said Javey, who is also a faculty scientist at the Lawrence Berkeley National Lab. “The light from a flashlight is enough to generate a response.”

The researchers described their experiments in a paper published this week in the journal Nature Communications. They were able to tweak the size and chirality – referring to the left or right direction of twist – of the nanotubes to make the material react to different wavelengths of light. The swaths of material they created, dubbed “smart curtains,” could bend or straighten in response to the flick of a light switch.

“We envision these in future smart, energy-efficient buildings,” said Javey. “Curtains made of this material could automatically open or close during the day.”  [emphasis mine]

Other potential applications include light-driven motors and robotics that move toward or away from light, the researchers said.

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

Photoactuators and motors based on carbon nanotubes with selective chirality distributions by Xiaobo Zhang, Zhibin Yu, Chuan Wang, David Zarrouk, Jung-Woo Ted Seo, Jim C. Cheng, Austin D. Buchan, Kuniharu Takei, Yang Zhao, Joel W. Ager, Junjun Zhang, Mark Hettick, Mark C. Hersam, Albert P. Pisano, Ronald S. Fearing, & Ali Javey. Nature Communications 5, Article number: 2983 doi:10.1038/ncomms3983 Published 07 January 2014

The earlier reference to energy-efficient buildings suggests that this work with light-activated curtains is another variation of a ‘smart’ window’ and bears some resemblance to Boris Lamontagne’s (Canada National Research Council) work with curling electrodes which act as blinds in his version of smart glass as per my .Sept. 16, 2011 posting.

Ali Javey has been mentioned here before in a Sept. 15, 2010 post concerning nanotechnology-enabled robot skin.