The Smell Of Death

Scientists in Korea have developed a bioelectronicnose’ that can specifically detect a key compound produced in decaying substances. When food begins to rot, the smell that we find repulsive comes from a compound known as cadaverine. That is also the substance responsible for the stench of rotting bodies, or cadavers—hence the name. The compound is the result of a bacterial reaction involving lysine, which is an amino acid commonly found in various food products. A previous study has shown that a receptor in zebrafish has an affinity for cadaverine. To make this receptor in the laboratory, scientists have turned to Escherichia coli bacteria as a host cell because it can easily produce large quantities of proteins. However, the production of this receptor in E. coli has been a challenge because it needs to be embedded in a membrane.

In this study, a team of researchers led by Associate Professor Hong Seunghun at Seoul National University packaged the cadaverine receptor from the zebrafish into nanodiscs, which are water friendly, membrane-like structures. The researchers then placed the receptor-containing nanodiscs in a special orientation on a carbon nanotube transistor, completing the bioelectronic nose. During testing with purified test compounds and real-world salmon and beef samples, the nose was selective and sensitive for cadaverine, even at low levels. The researchers suggest that the detector could someday prove useful in natural disaster scenarios, to recover corpses for identification.

The findings have been published in the journal ACS Nano.


How To Monitor and Combat Diabetes With A Simple Patch

In the future, diabetics may be able to replace finger prick tests and injections with this non-invasive smart patch to keep their glucose levels in check.


The device is a type of patch which enables diabetic patients to monitor blood sugar levels via sweat without taking blood samples and control glucose levels by injecting medication“, says Kim Dae-Hyeong, researcher at the Institute for Basic Science (IBS), Seoul National University, South Korea.

After analyzing the patient’s sweat to sense glucose, the patch’s embedded sensors constantly test pH, humidity, and temperature – important factors for accurate blood sugar readings. The graphene-based patch is studded with micro-needles coated with medication that pierce the skin painlessly. When the patch senses above normal glucose levels a tiny heating element switches on which dissolves the medication coating the microneedles and releases it into the body. The prototype worked well in mice trials.

Diabetic patients can easily use our device because it does not cause any pain or stress them out. So they can monitor and manage blood glucose levels more often to prevent increasing it. Therefore, our device can greatly contribute to helping patients avoid complications of the disease“, comments Professor Kim Dae-Hyeong. Researchers want to lower the cost of production, while figuring out how to delivery enough medication to effectively treat humans, both major hurdles towards commercialization. The research was published in the journal Nature Nanotechnology in March.


Smart Skin For Robots Simulating Sense Of Touch

It’s soft, warm, and can sense pressure, heat and humidity – just like human skin. This is ‘smartartificial skin and it’s the first to simulate the sense of touch. Its developers at South Korea’s Seoul National University say they aimed to create a material as close to human skin as possible.
prosthetic smart skin
We developed the synthetic skin which has the sense of feeling that exactly copies human skin. The skin can feel pressure, temperature, strain, humidity. Also it is soft, just like human skin, and embedded with heating elements that can make itself warm,” says Professor Kim Dae-Hong from the School of Chemical and Biological Engineering at Seoul National University. The warm prosthetic skin matches the temperature of the human body. And its layers give it its sense of touch.
The bottom layer of skin is rubbery material that can express the softness of human skin. Above the rubber layer, there is ultra thin polyimide and then silicon, which acts as sensors“, he adds. Researchers have combined their stretchy skin with a prosthetic hand and found it can be used for complex operations. Hand-shaking, keyboard-tapping and ball-grasping are all possible. And its humidity sensors mean it can even tell the difference between a dry diaper and a wet one. The researchers hope the ultra-thin skin will be able to send sensory signals to the brain. At the moment, this has only been demonstrated in small animals. But Professor Kim has high hopes for the future of his team’s prosthetic skin: “I hope a robotic limb with this synthetic skin can be used by disabled people. For industrial uses, it can be applied to various types of robots, like a humanoid robot“, he says. The developers envisage the synthetic skin being used by amputees. But a diaper-changing robot could also come in handy.

Liver Cancer: Hope Is Coming From Plants

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-associated death worldwide. Also called malignant hepatoma, HCC is the most common type of liver cancer. Most cases of HCC are secondary to either a viral hepatitis infection (hepatitis B or C) or cirrhosis (alcoholism being the most common cause of hepatic cirrhosis). These regrettably poor prognoses are due to the difficulty in treating this cancer using conventional chemotherapeutic drugs such as doxorubicin, epirubicin, cisplatin, 5-fluorouracil, etoposide or combinations therein. This may be attributed to that the conventional medicines are not able to reach in a sufficient concentration in the liver tumor cells at levels that are not harmful to the rest of the body.

Now a team of scientists, led by Prof. Taeghwan Hyeon at the Institute for Basic Science (IBS)/Seoul National University and Prof. Kam Man Hui at the National Cancer Center Singapore, has screened a library containing hundreds of natural products against a panel of HCC cells to search a better drug candidate. The screen uncovered a compound named triptolide, a traditional Chinese medicine isolated from the thunder god vine (Tripterygium wilfordii (Latin) or lei gong teng (Chinese)) which was found to be far more potent than current therapies. Studies from other researchers corroborate the findings as triptolide has also found to be very effective against several other malignant cancers including; pancreatic, neuroblastoma and cholangiocarcinoma. However this excitement was tempered when the drug was administered to mice as the increased potency was coupled with increased toxicity as well. Prof. Hyeon et al. endeavoured to alleviate the toxic burden by increasing the specific delivery of the drug to the tumor using a nanoformulation. The designed formulation was a pH-sensitive nanogel coated with the nucleotide precursor, folate.

Cigarette Butts Better Than Graphene To Store Energy

A group of scientists from South Korea have converted cigarette butts into a high-performing material that could be integrated into computers, handheld devices, electrical vehicles and wind turbines to store energy. Presenting their findings today, 5 August 2014, in IOP Publishing’s journal Nanotechnology, the researchers have demonstrated the material’s superior performance compared to commercially available carbon, graphene and carbon nanotubes. It is hoped the material can be used to coat the electrodes of supercapacitors electrochemical components that can store extremely large amounts of electrical energy – while also offering a solution to the growing environmental problem caused by used cigarette filters. It is estimated that as many as 5.6 trillion cigarette butts (equivalent to 766 571 metric tons), are deposited into the environment worldwide every year.

cigarette buttsOur study has shown that used cigarette filters can be transformed into a high-performing carbon-based material using a simple one-step process, which simultaneously offers a green solution to meeting the energy demands of society“, said co-author of the study Professor Jongheop Yi, from Seoul National University. “Numerous countries are developing strict regulations to avoid the trillions of toxic and non-biodegradable used cigarette filters that are disposed of into the environment each year; our method is just one way of achieving this.”


Scotch Magic Tape Makes Electronics Smaller and Better

An international group of researchers from the University of Minnesota, Argonne National Laboratory and Seoul National University have discovered a groundbreaking technique in manufacturing nanostructures that has the potential to make electrical and optical devices smaller and better than ever before. A surprising low-tech tool of Scotch Magic tape ended up being one of the keys to the discovery. Combining several standard nanofabrication techniques—with the final addition of the Scotch Magic tape—researchers at the University of Minnesota created extremely thin gaps through a layer of metal and patterned these tiny gaps over the entire surface of a four-inch silicon wafer. The smallest gaps were only one nanometer wide, much smaller than most researchers have been able to achieve. In addition, the widths of the gaps could be controlled on the atomic level. This work provides the basis for producing new and better nanostructures that are at the core of advanced electronic and optical devices.
Scotch magic tape

Our technology, called atomic layer lithography, has the potential to create ultra-small sensors with increased sensitivity and also enable new and exciting experiments at the nanoscale like we’ve never been able to do before,” said Sang-Hyun Oh, one of the lead researchers on the study and a professor of electrical and computer engineering in the University of Minnesota’s College of Science and Engineering. “This research also provides the basis for future studies to improve electronic and photonic devices.
The research has been published in Nature Communications.