Tag Archives: Jia Liu

Injectable electronics

Having taught a course on bioelectronics for Simon Fraser University’s (Vancouver, Canada) Continuing Studies Program, this  latest work from Harvard University (US) caught my attention. A Harvard research team has developed a technique which could allow doctors to inject us with electronics, should we need them. From a June 8, 2015 news item on phys.org,

It’s a notion that might be pulled from the pages of science-fiction novel – electronic devices that can be injected directly into the brain, or other body parts, and treat everything from neurodegenerative disorders to paralysis.

It sounds unlikely, until you visit Charles Lieber’s lab.

A team of international researchers, led by Lieber, the Mark Hyman, Jr. Professor of Chemistry, an international team of researchers developed a method for fabricating nano-scale electronic scaffolds that can be injected via syringe. Once connected to electronic devices, the scaffolds can be used to monitor neural activity, stimulate tissues and even promote regenerations of neurons. …

Here’s an image provided by the researchers,

Bright-field image showing the mesh electronics being injected through sub-100 micrometer inner diameter glass needle into aqueous solution. mage courtesy of Lieber Research Group, Harvard University

Bright-field image showing the mesh electronics being injected through sub-100 micrometer inner diameter glass needle into aqueous solution. mage courtesy of Lieber Research Group, Harvard University

A June 8, 2015 Harvard University new release by Peter Reuell (also on EurekAlert), which originated the news item, describes the work in more detail,

“I do feel that this has the potential to be revolutionary,” Lieber said. “This opens up a completely new frontier where we can explore the interface between electronic structures and biology. For the past thirty years, people have made incremental improvements in micro-fabrication techniques that have allowed us to make rigid probes smaller and smaller, but no one has addressed this issue – the electronics/cellular interface – at the level at which biology works.”

The idea of merging the biological with the electronic is not a new one for Lieber.

In an earlier study, scientists in Lieber’s lab demonstrated that the scaffolds could be used to create “cyborg” tissue – when cardiac or nerve cells were grown with embedded scaffolds. [emphasis mine] Researchers were then able to use the devices to record electrical signals generated by the tissues, and to measure changes in those signals as they administered cardio- or neuro-stimulating drugs.

“We were able to demonstrate that we could make this scaffold and culture cells within it, but we didn’t really have an idea how to insert that into pre-existing tissue,” Lieber said. “But if you want to study the brain or develop the tools to explore the brain-machine interface, you need to stick something into the body. When releasing the electronics scaffold completely from the fabrication substrate, we noticed that it was almost invisible and very flexible like a polymer and could literally be sucked into a glass needle or pipette. From there, we simply asked, would it be possible to deliver the mesh electronics by syringe needle injection, a process common to delivery of many species in biology and medicine – you could go to the doctor and you inject this and you’re wired up.'”

Though not the first attempts at implanting electronics into the brain – deep brain stimulation has been used to treat a variety of disorders for decades – the nano-fabricated scaffolds operate on a completely different scale.

“Existing techniques are crude relative to the way the brain is wired,” Lieber explained. “Whether it’s a silicon probe or flexible polymers…they cause inflammation in the tissue that requires periodically changing the position or the stimulation. But with our injectable electronics, it’s as if it’s not there at all. They are one million times more flexible than any state-of-the-art flexible electronics and have subcellular feature sizes. They’re what I call “neuro-philic” – they actually like to interact with neurons..”

Despite their enormous potential, the fabrication of the injectable scaffolds is surprisingly easy.

“That’s the beauty of this – it’s compatible with conventional manufacturing techniques,” Lieber said.

The process is similar to that used to etch microchips, and begins with a dissolvable layer deposited on a substrate. To create the scaffold, researchers lay out a mesh of nanowires sandwiched in layers of organic polymer. The first layer is then dissolved, leaving the flexible mesh, which can be drawn into a syringe needle and administered like any other injection.

After injection, the input/output of the mesh can be connected to standard measurement electronics so that the integrated devices can be addressed and used to stimulate or record neural activity.

“These type of things have never been done before, from both a fundamental neuroscience and medical perspective,” Lieber said. “It’s really exciting – there are a lot of potential applications.”

Going forward, Lieber said, researchers hope to better understand how the brain and other tissues react to the injectable electronics over longer periods.

Lieber’s earlier work on “cyborg tissue” was briefly mentioned here in a Feb. 20, 2014 posting.

Getting back to the most recent work, here’s a link to and a citation for the paper,

Syringe-injectable electronics by Jia Liu, Tian-Ming Fu, Zengguang Cheng, Guosong Hong, Tao Zhou, Lihua Jin, Madhavi Duvvuri, Zhe Jiang, Peter Kruskal, Chong Xie, Zhigang Suo, Ying Fang, & Charles M. Lieber. Nature Nanotechnology (2015) doi:10.1038/nnano.2015.115 Published online 08 June 2015

This paper is behind a paywall but there is a free preview via ReadCube Access.

One final note, the researchers have tested the injectable electronics (or mesh electronics) in vivo (live animals).

Making nanoelectronic devices last longer in the body could lead to ‘cyborg’ tissue

An American Chemical Society (ACS) Feb. 19, 2014 news release (also on EurekAlert), describes some research devoted to extending a nanoelectronic device’s ‘life’ when implanted in the body,

The debut of cyborgs who are part human and part machine may be a long way off, but researchers say they now may be getting closer. In a study published in ACS’ journal Nano Letters, they report development of a coating that makes nanoelectronics much more stable in conditions mimicking those in the human body. [emphases mine] The advance could also aid in the development of very small implanted medical devices for monitoring health and disease.

Charles Lieber and colleagues note that nanoelectronic devices with nanowire components have unique abilities to probe and interface with living cells. They are much smaller than most implanted medical devices used today. For example, a pacemaker that regulates the heart is the size of a U.S. 50-cent coin, but nanoelectronics are so small that several hundred such devices would fit in the period at the end of this sentence. Laboratory versions made of silicon nanowires can detect disease biomarkers and even single virus cells, or record heart cells as they beat. Lieber’s team also has integrated nanoelectronics into living tissues in three dimensions — creating a “cyborg tissue.” One obstacle to the practical, long-term use of these devices is that they typically fall apart within weeks or days when implanted. In the current study, the researchers set out to make them much more stable.

They found that coating silicon nanowires with a metal oxide shell allowed nanowire devices to last for several months. This was in conditions that mimicked the temperature and composition of the inside of the human body. In preliminary studies, one shell material appears to extend the lifespan of nanoelectronics to about two years.

Depending on how you define the term cyborg, it could be said there are already cyborgs amongst us as I noted in an April 20, 2012 posting titled: My mother is a cyborg. Personally I’m fascinated by the news release’s mention of ‘cyborg tissue’ although there’s no further explanation of what the term might mean.

For the curious, here’s a link to and a citation for the paper,

Long Term Stability of Nanowire Nanoelectronics in Physiological Environments by Wei Zhou, Xiaochuan Dai, Tian-Ming Fu, Chong Xie, Jia Liu, and Charles M. Lieber. Nano Lett., Article ASAP DOI: 10.1021/nl500070h Publication Date (Web): January 30, 2014
Copyright © 2014 American Chemical Society

This paper is behind a paywall.

Clone your carbon nanotubes

The Nov. 14, 2012 news release on EurekAlert highlights some work on a former nanomaterial superstar, carbon nanotubes,

Scientists and industry experts have long speculated that carbon nanotube transistors would one day replace their silicon predecessors. In 1998, Delft University built the world’s first carbon nanotube transistors – carbon nanotubes have the potential to be far smaller, faster, and consume less power than silicon transistors.

A key reason carbon nanotubes are not in your computer right now is that they are difficult to manufacture in a predictable way. Scientists have had a difficult time controlling the manufacture of nanotubes to the correct diameter, type and ultimately chirality, factors that control nanotubes’ electrical and mechanical properties.

Carbon nanotubes are typically grown using a chemical vapor deposition (CVD) system in which a chemical-laced gas is pumped into a chamber containing substrates with metal catalyst nanoparticles, upon which the nanotubes grow. It is generally believed that the diameters of the nanotubes are determined by the size of the catalytic metal nanoparticles. However, attempts to control the catalysts in hopes of achieving chirality-controlled nanotube growth have not been successful.

The USC [University of Southern California] team’s innovation was to jettison the catalyst and instead plant pieces of carbon nanotubes that have been separated and pre-selected based on chirality, using a nanotube separation technique developed and perfected by Zheng [Ming Zheng] and his coworkers at NIST [US National Institute of Standards and Technology]. Using those pieces as seeds, the team used chemical vapor deposition to extend the seeds to get much longer nanotubes, which were shown to have the same chirality as the seeds..

The process is referred to as “nanotube cloning.” The next steps in the research will be to carefully study the mechanism of the nanotube growth in this system, to scale up the cloning process to get large quantities of chirality-controlled nanotubes, and to use those nanotubes for electronic applications

H/T to ScienceDaily’s Nov. 14, 2012 news item for the full journal reference,

Jia Liu, Chuan Wang, Xiaomin Tu, Bilu Liu, Liang Chen, Ming Zheng, Chongwu Zhou. Chirality-controlled synthesis of single-wall carbon nanotubes using vapour-phase epitaxy. Nat. Commun., 13 Nov, 2012 DOI: 10.1038/ncomms2205

The article is behind a paywall.