How To Fix Duchenne Muscular Dystrophy

Scientists at the University of California, Berkeley, have engineered a new way to deliver CRISPR-Cas9 gene-editing technology inside cells and have demonstrated in mice that the technology can repair the mutation that causes Duchenne muscular dystrophy, a severe muscle-wasting disease. A new study shows that a single injection of CRISPR-Gold, as the new delivery system is called, into mice with Duchenne muscular dystrophy led to an 18-times-higher correction rate and a two-fold increase in a strength and agility test compared to control groups.

Since 2012, when study co-author Jennifer Doudna, a professor of molecular and cell biology and of chemistry at UC Berkeley, and colleague Emmanuelle Charpentier, of the Max Planck Institute for Infection Biology, repurposed the Cas9 protein to create a cheap, precise and easy-to-use gene editor, researchers have hoped that therapies based on CRISPR-Cas9 would one day revolutionize the treatment of genetic diseases. Yet developing treatments for genetic diseases remains a big challenge in medicine. This is because most genetic diseases can be cured only if the disease-causing gene mutation is corrected back to the normal sequence, and this is impossible to do with conventional therapeutics.

CRISPR/Cas9, however, can correct gene mutations by cutting the mutated DNA and triggering homology-directed DNA repair. However, strategies for safely delivering the necessary components (Cas9, guide RNA that directs Cas9 to a specific gene, and donor DNA) into cells need to be developed before the potential of CRISPR-Cas9-based therapeutics can be realized. A common technique to deliver CRISPR-Cas9 into cells employs viruses, but that technique has a number of complications. CRISPR-Gold does not need viruses.

In the new study, research lead by the laboratories of Berkeley bioengineering professors Niren Murthy and Irina Conboy demonstrated that their novel approach, called CRISPR-Gold because gold nanoparticles are a key component, can deliver Cas9 – the protein that binds and cuts DNA – along with guide RNA and donor DNA into the cells of a living organism to fix a gene mutation.

CRISPR-Gold is the first example of a delivery vehicle that can deliver all of the CRISPR components needed to correct gene mutations, without the use of viruses,” Murthy said.

The study was published in the journal Nature Biomedical Engineering.


Nanocomputer: How To Grow Atomically Thin Transistors

In an advance that helps pave the way for next-generation electronics and computing technologies—and possibly paper-thin gadgets —scientists with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) developed a way to chemically assemble transistors and circuits that are only a few atoms thick. What’s more, their method yields functional structures at a scale large enough to begin thinking about real-world applications and commercial scalability“This is a big step toward a scalable and repeatable way to build atomically thin electronics or pack more computing power in a smaller area,” says Xiang Zhang*, a senior scientist in Berkeley Lab’s Materials Sciences Division who led the study.

Their work is part of a new wave of research aimed at keeping pace with Moore’s Law, which holds that the number of transistors in an integrated circuit doubles approximately every two years. In order to keep this pace, scientists predict that integrated electronics will soon require transistors that measure less than ten nanometers in length (nanocomputer). Transistors are electronic switches, so they need to be able to turn on and off, which is a characteristic of semiconductors. However, at the nanometer scale, silicon transistors likely won’t be a good option. That’s because silicon is a bulk material, and as electronics made from silicon become smaller and smaller, their performance as switches dramatically decreases, which is a major roadblock for future electronics.

Researchers have looked to two-dimensional crystals that are only one molecule thick as alternative materials to keep up with Moore’s Law. These crystals aren’t subject to the constraints of silicon. In this vein, the Berkeley Lab scientists developed a way to seed a single-layered semiconductor, in this case the TMDC molybdenum disulfide (MoS2), into channels lithographically etched within a sheet of conducting graphene. The two atomic sheets meet to form nanometer-scale junctions that enable graphene to efficiently inject current into the MoS2. These junctions make atomically thin transistors.

assembly of 2D crystals
This schematic shows the chemical assembly of two-dimensional crystals. Graphene is first etched into channels and the TMDC molybdenum disulfide (MoS2) begins to nucleate around the edges and within the channel. On the edges, MoS2 slightly overlaps on top of the graphene. Finally, further growth results in MoS2 completely filling the channels.

This approach allows for the chemical assembly of electronic circuits, using two-dimensional materials, which show improved performance compared to using traditional metals to inject current into TMDCs,” says Mervin Zhao, a lead author and Ph.D. student in Zhang’s group at Berkeley Lab and UC Berkeley.

Optical and electron microscopy images, and spectroscopic mapping, confirmed various aspects related to the successful formation and functionality of the two-dimensional transistors. In addition, the scientists demonstrated the applicability of the structure by assembling it into the logic circuitry of an inverter. This further underscores the technology’s ability to lay the foundation for a chemically assembled atomic computer or nanocomputer, the scientists say. “Both of these two-dimensional crystals have been synthesized in the wafer scale in a way that is compatible with current semiconductor manufacturing. By integrating our technique with other growth systems, it’s possible that future computing can be done completely with atomically thin crystals,” says Zhao.

*Zhang also holds the Ernest S. Kuh Endowed Chair at the University of California (UC) Berkeley and is a member of the Kavli Energy NanoSciences Institute at Berkeley. Other scientists who contributed to the research include Mervin Zhao, Yu Ye, Yang Xia, Hanyu Zhu, Siqi Wang, and Yuan Wang from UC Berkeley as well as Yimo Han and David Muller from Cornell University.


Remote-Controlled Cyborg Beetles

Hard-wiring beetles for radio-controlled flight turns out to be a fitting way to learn more about their biology. Cyborg insect research led by engineers at UC Berkeley and Singapore’s Nanyang Technological University (NTU) is enabling new revelations about a muscle used by beetles for finely graded turns.

Research video showing remote-controlled steering of a giant flower beetle flying untethered. By strapping nanocomputers and wireless radios onto the backs of giant flower beetles and recording neuromuscular data as the bugs flew untethered, scientists determined that a muscle known for controlling the folding of wings was also critical to steering. The researchers then used that information to improve the precision of the beetles’ remote-controlled turns.

This study, published in the journal Current Biology, showcases the potential of wireless sensors in biological research. Research in this field could also lead to applications such as tools to aid search-and-rescue operations in areas too dangerous for humans.
cyborg beetle
What things would you have to strip out in terms of genes or in terms neurosystems to be left with a chassis that is effectively a flyable chassis. Why is an insect not a flying robot, because it has stuff in there that you would like to knock out and then get yourself a chassis“, says Michele Maharbiz, an associate professor in UC Berkeley’s Department of Electrical Engineering and Computer Sciences and the study’s principal investigator.. A chassis like you would find in a car. But while cars were designed with the sole purpose of driving, evolution has hardwired beetles for multiple functions, like mating and eating. All of these need to taken into account when developing a remote controlled beetle. The researchers have made much progress over the years. They have proven they can control the beetles with stimulation to both the brain and muscles. Maharbiz thinks a combination of both techniques will probably be needed to create an ideal cyborg beetle. “At a short term practical level I think that we could stand to build controlled flyers at very small scales this way, in other words using the best of electronics and the best of the natural world,“, adds Maharbiz.

Smart Bandage

Engineers at UC Berkeley are developing a new type of bandage that does far more than stanch the bleeding from a paper cut or scraped knee.

Associate professor Michel Maharbiz explains how the smart bandage works to detect bedsores. (UC Berkeley video by Roxanne Makasdjian and Phil Ebiner)
Thanks to advances in flexible electronics, the researchers, in collaboration with colleagues at UC San Francisco, have created a new “smart bandage” that uses electrical currents to detect early tissue damage from pressure ulcers, or bedsores, before they can be seen by human eyes – and while recovery is still possible.
The researchers exploited the electrical changes that occur when a healthy cell starts dying. They tested the thin, non-invasive bandage on the skin of rats and found that the device was able to detect varying degrees of tissue damage consistently across multiple animals.

smartbandage The smart bandage is fabricated by printing gold electrodes onto a thin piece of plastic. This flexible sensor uses impedance spectroscopy to detect bedsores that are invisible to the naked eye
We set out to create a type of bandage that could detect bedsores as they are forming, before the damage reaches the surface of the skin,” said Michel Maharbiz, a UC Berkeley associate professor of electrical engineering and computer sciences and head of the smart-bandage project. “We can imagine this being carried by a nurse for spot-checking target areas on a patient, or it could be incorporated into a wound dressing to regularly monitor how it’s healing.
The findings, published in the journal Nature Communications, could provide a major boost to efforts to stem a health problem that affects an estimated 2.5 million U.S. residents at an annual cost of $11 billion.


Highly Sensitive Whiskers For Robots

From the world of nanotechnology we’ve gotten electronic skin, or e-skin, and electronic eye implants or e-eyes. Now we’re on the verge of electronic whiskers. Researchers with Berkeley Lab and the University of California (UC) Berkeley have created tactile sensors from composite films of carbon nanotubes and silver nanoparticles similar to the highly sensitive whiskers of cats and rats. These new e-whiskers respond to pressure as slight as a single Pascal, about the pressure exerted on a table surface by a dollar bill. Among their many potential applications is giving robots new abilities to “see” and “feel” their surrounding environment.

E-whiskers are highly responsive tactile sensor networks made from carbon nanotubes and silver nanoparticles that resemble the whiskers of cats and other mammals
Whiskers are hair-like tactile sensors used by certain mammals and insects to monitor wind and navigate around obstacles in tight spaces,” says the leader of this research Ali Javey, a faculty scientist in Berkeley Lab’s Materials Sciences Division and a UC Berkeley professor of electrical engineering and computer science. “Our electronic whiskers consist of high-aspect-ratio elastic fibers coated with conductive composite films of nanotubes and nanoparticles. In tests, these whiskers were 10 times more sensitive to pressure than all previously reported capacitive or resistive pressure sensors.”


Solar Cells at the Price of Pocketbooks

Engineers at the University of California, Berkeley, have developed an inexpensive new way to grow thin films of a material prized in the semiconductor and photovoltaic industries, an achievement that could bring high-end solar cells within reach of consumer pocketbooks.

solar-satelliteUC Berkeley engineers could help make high-end solar cells, currently used in satellites and other space and military applications, affordable for consumer markets.
Performance is everything in the solar cell industry, but performance at a reasonable cost is key,” said Javey, who is also a faculty scientist at the Lawrence Berkeley National Laboratory. “The techniques we are reporting here should be a game-changer for III-V solar cells, as well as for LEDs.”

Top of the line photovoltaics are made from a class of material known as III-V (pronounced “three-five”) compounds, known for their superior efficiency at converting light into power. However, the complex manufacturing requirements for III-V materials make them up to 10 times more expensive than silicon, limiting their use to military applications and NASA satellites, the researchers said.

The work, led by Ali Javey, UC Berkeley associate professor of electrical engineering and computer sciences, is described in a paper published in Scientific Reports, Nature’s open access journal.

Nanotechnologies Help To Heal Nuclear Damages

Researchers at the California Institute of Technology (Caltech) have brought new understanding to one of those secrets — how the interfaces between two carefully selected metals can absorb, or heal, radiation damage. Some nano-engineered materials are able to resist such damage and may, for example, prevent helium bubbles from coalescing into larger voids. For instance, some metallic nanolaminates—materials made up of extremely thin alternating layers of different metals—are able to absorb various types of radiation-induced defects at the interfaces between the layers because of the mismatch that exists between their crystal structures.

When it comes to selecting proper structural materials for advanced nuclear reactors, it is crucial that we understand radiation damage and its effects on materials properties. And we need to study these effects on isolated small-scale features,” says Julia R. Greer, an assistant professor of materials science and mechanics at Caltech. With that in mind, Greer and colleagues from Caltech, Sandia National Laboratories, UC Berkeley, and Los Alamos National Laboratory have taken a closer look at radiation-induced damage, zooming in all the way to the nanoscale — where lengths are measured in billionths of meters.
Their results appear online in the journals Advanced Functional Materials and Small.