Tag Archives: University of Tokyo

Nanomachines To Deliver Cancer Drugs to Hard-to-reach Areas

In a recent study in mice, researchers found a way to deliver specific drugs to parts of the body that are exceptionally difficult to access. Their Y-shaped block catiomer (YBC) binds with certain therapeutic materials forming a package 18 nanometers wide. The package is less than one-fifth the size of those produced in previous studies, so can pass through much smaller gaps. This allows YBCs to slip through tight barriers in cancers of the brain or pancreas.

The fight against cancer is fought on many fronts. One promising field is gene therapy, which targets genetic causes of diseases to reduce their effect. The idea is to inject a nucleic acid-based drug into the bloodstream — typically small interfering RNA (siRNA) — which binds to a specific problem-causing gene and deactivates it. However, siRNA is very fragile and needs to be protected within a nanoparticle or it breaks down before reaching its target.

siRNA can switch off specific gene expressions that may cause harm. They are the next generation of biopharmaceuticals that could treat various intractable diseases, including cancer,” explained Associate Professor Kanjiro Miyata of the University of Tokyo, who jointly supervised the study. “However, siRNA is easily eliminated from the body by enzymatic degradation or excretion. Clearly a new delivery method was called for.”

Presently, nanoparticles are about 100 nanometers wide, one-thousandth the thickness of paper. This is small enough to grant them access to the liver through the leaky blood vessel wall. However some cancers are harder to reach. Pancreatic cancer is surrounded by fibrous tissues and cancers in the brain by tightly connected vascular cells. In both cases the gaps available are much smaller than 100 nanometers. Miyata and colleagues created an siRNA carrier small enough to slip through these gaps in the tissues.

We used polymers to fabricate a small and stable nanomachine for the delivery of siRNA drugs to cancer tissues with a tight access barrier,” said Miyata. “The shape and length of component polymers is precisely adjusted to bind to specific siRNAs, so it is configurable.”

Source: https://www.u-tokyo.ac.jp/

Flying Robot

If your robot doesn’t weigh anything, you don’t have to worry about falling over, Researchers from the University of Tokyo have developed a quadrotor with legs called Aerial-Biped. Designed primarily for entertainment, Aerial-Biped enables “a richer physical expression” by automatically generating walking gaits in sync with its quadrotor body.

Until someone invents a robot that can moonwalk, you can model a gait that appears normal by simply making sure that the velocity of a foot is zero as long as it’s in contact with the ground. The Aerial-Biped robot learns how to do this through reinforcement learning in a physics simulator, and the policy transfers to the robot well enough that the legs can appear to walk as the quadrotor moves.

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The lead author Azumi Maekawa from the University of Tokyo explained: . “We were inspired by bipedal robots that use invisible force to get stability, such as Magdan, created by Tomotaka Takahashi (an electromagnet on the bottom of its feet lets it walk on a metal plate), and BALLU (which uses buoyancy of a helium-filled balloon). The foot trajectory generation method is based on the assumption that one of the key features of walking (or at least the appearance of walking) is that the velocity of the foot in contact with the ground is zero. The goal is to develop a robot that has the ability to display the appearance of bipedal walking with dynamic mobility, and to provide a new visual experience. 

Source: https://spectrum.ieee.org/

A self-powered heart monitor taped to the skin

Scientists in Japan have developed a human-friendly, ultra-flexible organic sensor powered by sunlight, which acts as a self-powered heart monitor. Previously, they developed a flexible photovoltaic cell that could be incorporated into textiles. In this study, they directly integrated a sensory device, called an organic electrochemical transistor—a type of electronic device that can be used to measure a variety of biological functions—into a flexible organic solar cell. Using it, they were then able to measure the heartbeats of rats and humans under bright light conditions.

Self-powered devices that can be fit directly on human skin or tissue have great potential for medical applications. They could be used as physiological sensors for the real-time  or the real-time monitoring of heart or brain function in the human body. However, practical realization has been impractical due to the bulkiness of batteries and insufficient power supply, or due to noise interference from the electrical supply, impeding conformability and long-term operation.

The key requirement for such devices is a stable and adequate energy supply. A key advance in this study, published in Nature, is the use of a nano-grating surface on the light absorbers of the solar cell, allowing for high photo-conversion efficiency (PCE) and light angle independency. Thanks to this, the researchers were able to achieve a PCE of 10.5 percent and a high power-per-weight ratio of 11.46 watts per gram, approaching the “magic number” of 15 percent that will make organic photovoltaics competitive with their silicon-based counterparts.

To demonstrate a practical application, sensory devices called organic electrochemical transistors were integrated with organic solar cells on an ultra-thin (1 μm) substrate, to allow the self-powered detection of heartbeats either on the skin or to record electrocardiographic (ECG) signals directly on the heart of a rat. They found that the device worked well at a lighting level of 10,000 lux, which is equivalent to the light seen when one is in the shade on a clear sunny day, and experienced less noise than similar devices connected to a battery, presumably because of the lack of electric wires.

According to Kenjiro Fukuda of the RIKEN Center for Emergent Matter Science, “This is a nice step forward in the quest to make self-powered medical monitoring devices that can be placed on human tissue. There are some important remaining tasks, such as the development of flexible power storage devices, and we will continue to collaborate with other groups to produce practical devices. Importantly, for the current experiments we worked on the analog part of our device, which powers the device and conducts the measurement. There is also a digital silicon-based portion, for the transmission of data, and further work in that area will also help to make such devices practical.

The research was carried out by RIKEN in collaboration with researchers from the University of Tokyo.

Source: http://www.riken.jp/