Nano-Implant Could Restore Sight

A team of engineers at the University of California San Diego (UC San Diego)  and La Jolla-based startup Nanovision Biosciences Inc. have developed the nanotechnology and wireless electronics for a new type of retinal prosthesis that brings research a step closer to restoring the ability of neurons in the retina to respond to light. The researchers demonstrated this response to light in a rat retina interfacing with a prototype of the device in vitro. The technology could help tens of millions of people worldwide suffering from neurodegenerative diseases that affect eyesight, including macular degeneration, retinitis pigmentosa and loss of vision due to diabetes.

Despite tremendous advances in the development of retinal prostheses over the past two decades, the performance of devices currently on the market to help the blind regain functional vision is still severely limited—well under the acuity threshold of 20/200 that defines legal blindness.

cortical neuronsPrimary cortical neurons cultured on the surface of an array of optoelectronic nanowires. Note the extensive neurite outgrowth and network formation

We want to create a new class of devices with drastically improved capabilities to help people with impaired vision,” said Gabriel A. Silva, one of the senior authors of the work and professor in bioengineering and ophthalmology at UC San Diego. Silva also is one of the original founders of Nanovision.

Power is delivered wirelessly, from outside the body to the implant, through an inductive powering telemetry system developed by a team led by Cauwenberghs.

The device is highly energy efficient because it minimizes energy losses in wireless power and data transmission and in the stimulation process, recycling electrostatic energy circulating within the inductive resonant tank, and between capacitance on the electrodes and the resonant tank. Up to 90 percent of the energy transmitted is actually delivered and used for stimulation, which means less RF wireless power emitting radiation in the transmission, and less heating of the surrounding tissue from dissipated power. For proof-of-concept, the researchers inserted the wirelessly powered nanowire array beneath a transgenic rat retina with rhodopsin P23H knock-in retinal degeneration.

The findings are published in a recent issue of the Journal of Neural Engineering.

Source: http://ucsdnews.ucsd.edu/

 

Self-healing Materials

A team of engineers at the University of California San Diego has developed a magnetic ink that can be used to make self-healing batteries, electrochemical sensors and wearable, textile-based electrical circuits. The key ingredient for the ink is microparticles oriented in a certain configuration by a magnetic field. Because of the way they’re oriented, particles on both sides of a tear are magnetically attracted to one another, causing a device printed with the ink to heal itself. The devices repair tears as wide as 3 millimeters—a record in the field of self-healing systems.

self-healing-wearable

Our work holds considerable promise for widespread practical applications for long-lasting printed electronic devices,” said Joseph Wang, director of the Center for Wearable Sensors and chair of the nanoengineering department at UC San Diego.

Existing self-healing materials require an external trigger to kick start the healing process. They also take anywhere between a few minutes to several days to work. By contrast, the system developed by Wang and colleagues doesn’t require any outside catalyst to work. Damage is repaired within about 50 milliseconds (0.05 seconds).

Engineers used the ink to print batteries, electrochemical sensors and wearable, textile-based electrical circuits. They then set about damaging these devices by cutting them and pulling them apart to create increasingly wide gaps. Researchers repeatedly damaged the devices nine times at the same location. They also inflicted damage in four different places on the same device. The devices still healed themselves and recovered their function while losing a minimum amount of conductivity.

For example, nanoengineers printed a self-healing circuit on the sleeve of a T-shirt and connected it with an LED light and a coin battery. The researchers then cut the circuit and the fabric it was printed on. At that point, the LED turned off. But then within a few seconds it started turning back on as the two sides of the circuit came together again and healed themselves, restoring conductivity.

Researchers detail their findings in the journal Science Advances.

Source: http://ucsdnews.ucsd.edu/

Light Makes OscillatorTo Oscillate Indefinitely

Researchers have designed a device that uses light to manipulate its mechanical properties. The device, which was fabricated using a plasmomechanical metamaterial, operates through a unique mechanism that couples its optical and mechanical resonances, enabling it to oscillate indefinitely using energy absorbed from light.

metamaterialThis work demonstrates a metamaterial-based approach to develop an optically-driven mechanical oscillator. The device can potentially be used as a new frequency reference to accurately keep time in GPS, computers, wristwatches and other devices, researchers said. Other potential applications that could be derived from this metamaterial-based platform include high precision sensors and quantum transducers..

Researchers engineered the metamaterial-based device by integrating tiny light absorbing nanoantennas onto nanomechanical oscillators. The study was led by Ertugrul Cubukcu, a professor of nanoengineering and electrical engineering at the University of California San Diego. The work, which Cubukcu started as a faculty member at the University of Pennsylvania and is continuing at the Jacobs School of Engineering at UC San Diego, demonstrates how efficient light-matter interactions can be utilized for applications in novel nanoscale devices.

Metamaterials are artificial materials that are engineered to exhibit exotic properties not found in nature. For example, metamaterials can be designed to manipulate light, sound and heat waves in ways that can’t typically be done with conventional materials.

Metamaterials are generally considered “lossy” because their metal components absorb light very efficiently. “The lossy trait of metamaterials is considered a nuisance in photonics applications and telecommunications systems, where you have to transmit a lot of power. We’re presenting a unique metamaterials approach by taking advantage of this lossy feature,” Cubukcu said. The researchers also point out that because the plasmomechanical metamaterial can efficiently absorb light, it can function under a broad optical resonance. That means this metamaterial can potentially respond to a light source like an LED and won’t need a strong laser to provide the energy.

Using plasmonic metamaterials, we were able to design and fabricate a device that can utilize light to amplify or dampen microscopic mechanical motion more powerfully than other devices that demonstrate these effects. Even a non-laser light source could still work on this device,” said Hai Zhu, a former graduate student in Cubukcu’s lab and first author of the study.

Optical metamaterials enable the chip-level integration of functionalities such as light-focusing, spectral selectivity and polarization control that are usually performed by conventional optical components such as lenses, optical filters and polarizers. Our particular metamaterial-based approach can extend these effects across the electromagnetic spectrum,” adds Fei Yi, a postdoctoral researcher who worked in Cubukcu’s lab.

The research was published in the journal Nature Photonics.

Source: http://jacobsschool.ucsd.edu/

Biosensor Chip Detects DNA Mutations

Bioengineers at the University of California, San Diego have developed an electrical graphene chip capable of detecting mutations in DNA. Researchers say the technology could one day be used in various medical applications such as blood-based tests for early cancer screening, monitoring disease biomarkers and real-time detection of viral and microbial sequences.

biosensor chip SNP detection

We are at the forefront of developing a fast and inexpensive digital method to detect gene mutations at high resolution—on the scale of a single nucleotide change in a nucleic acid sequence,” said Ratnesh Lal, professor of bioengineering, mechanical engineering and materials science in the Jacobs School of Engineering at UC San Diego.

The technology, which is at a proof-of-concept stage, is a first step toward a biosensor chip that can be implanted in the body to detect a specific DNA mutation—in real time—and transmit the information wirelessly to a mobile device such as a smartphone or laptop.

The advance was published June 13 in the online early edition of Proceedings of the National Academy of Sciences.

Source: http://jacobsschool.ucsd.edu/

Impenetrable Body-Armor To Protect Soldiers

A team of engineers from the University of California San Diego (UC San Diego) has developed and tested a type of steel with a record-breaking ability to withstand an impact without deforming permanently. The new steel alloy could be used in a wide range of applications, from drill bits, to body armor for soldiers, to meteor-resistant casings for satellites. The material is an amorphous steel alloy, a promising subclass of steel alloys made of arrangements of atoms that deviate from steel’s classical crystal-like structure, where iron atoms occupy specific locations.

Researchers are increasingly looking to amorphous steel as a source of new materials that are affordable to manufacture, incredibly hard, but at the same time, not brittle. The researchers believe their work on the steel alloy, named SAM2X5-630, is the first to investigate how amorphous steels respond to shock. SAM2X5-630 has the highest recorded elastic limit for any steel alloy, according to the researchers—essentially the highest threshold at which the material can withstand an impact without deforming permanently. The alloy can withstand pressure and stress of up to 12.5 giga-Pascals or about 125,000 atmospheres without undergoing permanent deformations.

record breaking steelTransmission electron microscopy image showing different levels of crystallinity embedded in the amorphous matrix of the alloy. Watch a video of the alloy being tested, click the image.
Because these materials are designed to withstand extreme conditions, you can process them under extreme conditions successfully,” said Olivia Graeve, a professor of mechanical engineering at the Jacobs School of Engineering at UC San Diego, who led the design and fabrication effort. Veronica Eliasson, an assistant professor at USC, led the testing efforts.

The researchers, from the University of California, San Diego, the University of Southern California and the California Institute of Technology, describe the material’s fabrication and testing in a recent issue of Nature Scientific Reports.

Source: http://jacobsschool.ucsd.edu/

How To Remove Nanoparticles From Blood

Engineers at the University of California, San Diego developed a new technology that uses an oscillating electric field to easily and quickly isolate drug-delivery nanoparticles from blood. The technology could serve as a general tool to separate and recover nanoparticles from other complex fluids for medical, environmental, and industrial applications.

Nanoparticles, which are generally one thousand times smaller than the width of a human hair, are difficult to separate from plasma, the liquid component of blood, due to their small size and low density. Traditional methods to remove nanoparticles from plasma samples typically involve diluting the plasma, adding a high concentration sugar solution to the plasma and spinning it in a centrifuge, or attaching a targeting agent to the surface of the nanoparticles. These methods either alter the normal behavior of the nanoparticles or cannot be applied to some of the most common nanoparticle types.

nanoparticles in blood

Nanoparticle removal chip developed by researchers in Professor Michael Heller’s lab at the UC San Diego Jacobs School of Engineering. An oscillating electric field (purple arcs) separates drug-delivery nanoparticles (yellow spheres) from blood (red spheres) and pulls them towards rings surrounding the chip’s electrodes.

This is the first example of isolating a wide range of nanoparticles out of plasma with a minimum amount of manipulation,” said Stuart Ibsen, a postdoctoral fellow in the Department of NanoEngineering at UC San Diego and first author of the study published October in the journal Small.
We’ve designed a very versatile technique that can be used to recover nanoparticles in a lot of different processes.”

Source: http://ucsdnews.ucsd.edu/

Ocean: NanoMotors Remove Ninety Percent Of The Carbon Dioxide

Machines that are much smaller than the width of a human hair could one day help clean up carbon dioxide pollution in the oceans. Nanoengineers at the University of California, San Diego have designed enzyme-functionalized micromotors that rapidly zoom around in water, remove carbon dioxide and convert it into a usable solid form. The proof of concept study represents a promising route to mitigate the buildup of carbon dioxide, a major greenhouse gas in the environment, said researchers.

nanomotorsNanoengineers have invented tiny tube-shaped micromotors that zoom around in water and efficiently remove carbon dioxide. The surfaces of the micromotors are functionalized with the enzyme carbonic anhydrase, which enables the motors to help rapidly convert carbon dioxide to calcium carbonate

We’re excited about the possibility of using these micromotors to combat ocean acidification and global warming,” said Virendra V. Singh, a postdoctoral scientist in Wang’s research group and a co-first author of this study. In their experiments, nanoengineers demonstrated that the micromotors rapidly decarbonated water solutions that were saturated with carbon dioxide. Within five minutes, the micromotors removed 90 percent of the carbon dioxide from a solution of deionized water. The micromotors were just as effective in a sea water solution and removed 88 percent of the carbon dioxide in the same timeframe.

In the future, we could potentially use these micromotors as part of a water treatment system, like a water decarbonation plant,” said Kevin Kaufmann, an undergraduate researcher in Wang’s lab and a co-author of the study.

The team, led by nanoengineering professor Joseph Wang, has published the work this month in the journal Angewandte Chemie.

Source: http://ucsdnews.ucsd.edu/

Smart Clothes Maintain The Confortable Temperature

Imagine a fabric that will keep your body at a comfortable temperature—regardless of how hot or cold it actually is. That’s the goal of an engineering project at the University of California, San Diego, funded with a $2.6M grant from the U.S. Department of Energy’s Advanced Research Projects Agency – Energy (ARPA-E). Wearing this smart fabric could potentially reduce heating and air conditioning bills for buildings and homes.

The project, named ATTACH (Adaptive Textiles Technology with Active Cooling and Heating), is led by Joseph Wang, distinguished professor of nanoengineering at UC San Diego.

By regulating the temperature around an individual person, rather than a large room, the smart fabric could potentially cut the energy use of buildings and homes by at least 15 percent, Wang noted.

T-shirt with printed electrodes

Garment-based printable electrodes developed in the lab of Joseph Wang, distinguished professor of nanoengineering at UC San Diego, and lead principal investigator of ATTACH

In cases where there are only one or two people in a large room, it’s not cost-effective to heat or cool the entire room,” said Wang. “If you can do it locally, like you can in a car by heating just the car seat instead of the entire car, then you can save a lot of energy.”

93° F (33,9° Celsius) is the average comfortable skin temperature for most people,” added Renkun Chen, assistant professor of mechanical and aerospace engineering at UC San Diego, and one of the collaborators on this project.

Chen’s contribution to ATTACH is to develop supplemental heating and cooling devices, called thermoelectrics, that are printable and will be incorporated into specific spots of the smart fabric. The thermoelectrics will regulate the temperature on “hot spots”—such as areas on the back and underneath the feet—that tend to get hotter than other parts of the body when a person is active.

This is like a personalized air-conditioner and heater,” said Chen. “With the smart fabric, you won’t need to heat the room as much in the winter, and you won’t need to cool the room down as much in the summer. That means less energy is consumed. Plus, you will still feel comfortable within a wider temperature range,” he added.

The researchers are also designing the smart fabric to power itself.

Source: http://www.jacobsschool.ucsd.edu/

Nanoparticle Kills Bacteria Associated With Gastric Cancer

The bacterium Helicobacter pylori is strongly associated with gastric ulcers and cancer. To combat the infection, researchers at University of California, San Diego School of Medicine and Jacobs School of Engineering developed LipoLLA, a therapeutic nanoparticle that contains linolenic acid, a component in vegetable oils. In mice, LipoLLA was safe and more effective against H. pylori infection than standard antibiotic treatments.
Helicobacter pylori
Current H. pylori treatments are facing a major challenge — antibiotic resistance,” said Liangfang Zhang, PhD, professor in the UC San Diego Moores Cancer Center and Department of Nanoengineering. “Our goal was to develop a nanotherapeutic that can tolerate the harsh gastric environment, kill H. pylori and avoid resistance.” Zhang and Marygorret Obonyo, PhD, assistant professor in the Moores Cancer Center and Department of Medicine, are co-senior authors of the study.

The results are published online Nov. 24 in the Proceedings of the National Academy of Sciences.
Source: http://ucsdnews.ucsd.edu/

Bacterial FM Radio

A team of biologists and engineers at the University of California San Diego (UC San Diego) develop a bacterial “FM Radio”. Objective: Programming living cells to offer the prospect of harnessing sophisticated biological machinery for transformative applications in energy, agriculture, water remediation and medicine. Inspired by engineering, researchers in the emerging field of synthetic biology have designed a tool box of small genetic components that act as intracellular switches, logic gates, counters and oscillators.

Independent genetic circuits are linked within single cells, illustrated under the magnifying glass, then coupled via quorum sensing at the colony level. But scientists have found it difficult to wire the components together to form larger circuits that can function as “genetic programs.” One of the biggest obstacles? Dealing with a small number of available wires.
The team’s breakthrough involves a form of “frequency multiplexing” inspired by FM radio.
This circuit lets us encode multiple independent environmental inputs into a single time series,” said Arthur Prindle, a bioengineering graduate student at UC San Diego and the first author of the study. “Multiple pieces of information are transferred using the same part. It works by using distinct frequencies to transmit different signals on a common channel.”
The findings have been published in this week’s advance online publication of the journal Nature.

Source: http://ucsdnews.ucsd.edu/

Nanosponges Soak Up Toxins Released By Bacterial Infections

Engineers at the University of California, San Diego have invented a “nanosponge” capable of safely removing a broad class of dangerous toxins from the bloodstream – including toxins produced by MRSA, E. coli, poisonous snakes and bees. These nanosponges, which thus far have been studied in mice, can neutralize “pore-forming toxins,” which destroy cells by poking holes in their cell membranes. Unlike other anti-toxin platforms that need to be custom synthesized for individual toxin type, the nanosponges can absorb different pore-forming toxins regardless of their molecular structures. In a study against alpha-haemolysin toxin from MRSA, pre-innoculation with nanosponges enabled 89 percent of mice to survive lethal doses. Administering nanosponges after the lethal dose led to 44 percent survival. Methicillin-resistant Staphylococcus aureus (MRSA) infection is caused by a strain of staph bacteria that’s become resistant to the antibiotics commonly used to treat ordinary staph infections.

nanosponge
“One of the first applications we are aiming for would be an anti-virulence treatment for MRSA. That’s why we studied one of the most virulent toxins from MRSA in our experiments,” said “Jack” Che-Ming Hu, the first author on the paper. The team, led by nanoengineers at the UC San Diego Jacobs School of Engineering, published the findings in Nature Nanotechnology April 14.
Source: http://www.eurekalert.org/