Tag Archives: bioenergy harvesting

Artificial nose for intelligent olfactory substitution

The signal transmitted into mouse brain can participate in mouse perception and act as the brain stimulator. (Image credit: Prof. ZHAN Yang)

I’m fascinated by the image. Are they suggesting putting implants into people’s brains that can sense dangerous gaseous molecules and convert that into data which can be read on a smartphone? And, are they harvesting bioenergy to supply energy to the implant?

A July 29, 2019 news item on Azonano was not as helpful in answering my questions as I’d hoped (Note: A link has been removed),

An artificial olfactory system based on a self-powered nano-generator has been built by Prof. ZHAN Yang’s team at the Shenzhen Institutes of Advanced Technology (SIAT) of the Chinese Academy of Sciences [CAS], together with colleagues at the University of Electronic Science and Technology of China.

The device, which can detect a variety of odor molecules and identify different odors, has been demonstrated in vivo in animal models. The research titled “An artificial triboelectricity-brain-behavior closed loop for intelligent olfactory substitution” has been reported in Nano Energy.

A July 25, 2019 CAS press release, which originated the news item, provides a little more information,

Odor processing is important to many species. Specific olfactory receptors located on the neurons are involved in odor recognition. These different olfactory receptors form patterned distribution.

Inspired by the biological receptors, the teams collaborated on formulating an artificial olfactory system. Through nano-fabrication on the soft materials and special alignment of material structures, the teams built a self-power device that can code and differentiate different odorant molecules.

This device has been connected to the mouse brain to demonstrate that the olfactory signals can produce appropriate neural stimulation. When the self-powered device generated the electric currents, the mouse displayed behavioral motion changes.

This study, inspired by the biological olfactory system, provides insights on novel design of neural stimulation and brain-machine interface. 

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

An artificial triboelectricity-brain-behavior closed loop for intelligent olfactory substitution by Tianyan Zhong, Mengyang Zhang, Yongming Fu, Yechao Han, Hongye Guan, Haoxuan He, Tianming Zhao, Lili Xing, Xinyu Xue, Yan Zhang, Yang Zhan.Nano Energy Volume 63, September 2019, 103884 DOI: https://doi.org/10.1016/j.nanoen.2019.103884

This paper is behind a paywall.

Harvesting bioenergy to cure wounds and control weight

I’m always a sucker for bioenergy harvesting stories but this is the first time I’ve seen research on the topic which combines weight control with wound healing. From a January 17, 2019 news item on Nanowerk,

Although electrical stimulation has therapeutic potential for various disorders and conditions, ungainly power sources have hampered practical applications. Now bioengineers have developed implantable and wearable nanogenerators from special materials that create electrical pulses when compressed by body motions. The pulses controlled weight gain and enhanced healing of skin wounds in rat models.

The work was performed by a research team led by Xudong Wang, Ph.D., Professor of Material Sciences and Engineering, College of Engineering, University of Wisconsin-Madison, and supported by the [US Dept. of Health, National Institutes of Health] National Institute of Biomedical Imaging and Bioengineering (NIBIB).

A January 17, 2019 NIBIB news release, which originated the news item, provides more technical information (Note: Links have been removed),

The researchers used what are known as piezoelectric and dielectric materials, including ceramics and crystals, which have a special property of creating an electrical charge in response to mechanical stress.

“Wang and colleagues have engineered solutions to a number of technical hurdles to create piezoelectric and dielectric materials that are compatible with body tissues and can generate a reliable, self-sufficient power supply. Their meticulous work has enabled a simple and elegant technology that offers the possibility of developing electrical stimulation therapies for a number of major diseases that currently lack adequate treatments,” explained David Rampulla, Ph.D., director of the Program in Biomaterials and Biomolecular Constructs at NIBIB

Shedding weight by curbing appetite

Worldwide, more than 700 million people — over 100 million of them children — are obese, causing health problems such as cardiovascular disease, diabetes, kidney disease, and certain cancers. In 2015 approximately four million people died of obesity-related causes1.

To address this crisis, Wang and his colleagues developed a vagal nerve stimulator (VNS) that dramatically improves appetite suppression through electrical stimulation of the vagus nerve. The approach is a promising one that has previously not proven practical because patients must carry bulky battery packs that require proper programming, and frequent recharging

The VNS consists of a small patch, about the size of a fingernail, which carries tiny devices called nanogenerators. Minimally invasive surgery was used to attach the VNS to the stomachs of rats. The rat’s stomach movements resulted in the delivery of gentle electrical pulses to the vagus nerve, which links the brain to the stomach. With the VNS, when the stomach moved in response to eating, the electric signal told the brain that the stomach was full, even if only a small amount of food was consumed.

The device curbed the rat’s appetite and reduced body weight by a remarkable 40 percent. “The stimulation is a natural response to regulate food intake, so there are no unwanted side effects,” explained Wang. When the device was removed the rats resumed their normal eating patterns and their weight returned to pre-treatment levels.

“Given the simplicity and effectiveness of the system, coupled with the fact that the effect is reversible and carries no side-effects, we are now planning testing in larger animals with the hope of eventually moving into human trials,” said Wang.

Accelerating wound healing

In another NIBIB-funded study in a rat experimental model, the researchers used their nanogenerator technology to determine whether electrical stimulation would accelerate healing of wounds on the skin surface.

For this experiment, a band of nanogenerators was placed around the rat’s chest, where the expansion from breathing created a mild electric field. Small electrodes in a bandage-like device were placed over skin wounds on the rat’s back, where they directed the electric field to cover the wound area.

The technique reduced healing times to just three days compared with nearly two weeks for the normal healing process.

Similar to the case with appetite suppression, it was known that electricity could enhance wound healing, but the devices that had been developed were large and impractical. The nanogenerator-powered bandage is completely non-invasive and produced a mild electric field that is similar to electrical activity detected in the normal wound-healing process.

The researchers observed electrical activation of normal cellular healing processes that included the movement of healthy skin fibroblasts into the wound, accompanied by the release of biochemical factors that promote the growth of the fibroblasts and other cell types that expand to repair the wound space.

“The dramatic decrease in healing time was surprising,” said Wang, “We now plan to test the device on pigs because their skin is very similar to humans.” 

The team believes the simplicity of the electric bandage will help move the technology to human trials quickly. In addition, Wang explained that the fabrication of the device is very inexpensive and a product for human use would cost about the same as a normal bandage.

The experiments on appetite suppression were reported in the December issue of Nature Communications2. The wound-healing studies were reported in the December issue of ACS Nano3. Both studies were supported by grant EB021336 from the National Institute of Biomedical Imaging and Bioengineering, and grant CA014520 from the National Cancer Institute.

Here are links to and citations for the papers,

Effective weight control via an implanted self-powered vagus nerve stimulation device by Guang Yao, Lei Kang, Jun Li, Yin Long, Hao Wei, Carolina A. Ferreira, Justin J. Jeffery, Yuan Lin, Weibo Cai & Xudong Wang. Nature Communications volume 9, Article number: 5349 (2018) DOI: https://doi.org/10.1038/s41467-018-07764-z Published 17 December 2018

Effective Wound Healing Enabled by Discrete Alternative Electric Fields from Wearable Nanogenerators by Yin Long, Hao Wei, Jun Li, Guang Yao, Bo Yu, Dalong Ni, Angela LF Gibson, Xiaoli Lan, Yadong Jiang, Weibo Cai, and Xudong Wang. ACS Nano, 2018, 12 (12), pp 12533–12540 DOI: 10.1021/acsnano.8b07038 Publication Date (Web): November 29, 2018

Copyright © 2018 American Chemical Society

Both papers are open access.