Graphene is an atomic-scale honeycomb lattice made of carbon atoms. It is the first 2D material ever created and one million times thinner than a human hair. It is a lot lighter and more flexible than steel, but many times stronger. It is transparent and thermally and electrically conductive. Due to its potential uses in creating nanocomposites, sensors, supercapacitors, hydrogen storage, photonics, and optoelectronic devices, graphene, a single layer of graphite, has generated a lot of interest.

Following are two recent interesting findings about graphene.

Graphene makes thinnest heart implant ever

A research team led by Northwestern University and the University of Texas at Austin has developed the thinnest cardiac implant ever made of graphene, according to a paper published in Advanced Materials.

The new graphene implant resembles a disposable tattoo in appearance and is no thicker than a hair, but still functions like a traditional pacemaker. Unlike current pacemakers and implantable defibrillators, the new device gently fuses with the heart while detecting and treating arrhythmias. It is thin and flexible to fit the delicate contours of the heart, but also has enough elasticity and strength to withstand the beating of the heart.

The study demonstrated that after implanting the device in a rat model, the graphene "sticker" successfully sensed irregular heart rates and delivered electrical stimulation through a series of pulses without restricting or altering the heart's natural beating. Additionally, the graphene implant is optically transparent, allowing the researchers to use an external light source to record conditions and stimulate the heart through the device.

Arrhythmia occurs when the heart beats too fast or too slow. In severe cases, arrhythmias can lead to heart failure, stroke and even sudden death. Doctors typically treat it with implanted pacemakers and defibrillators, devices that detect abnormal heartbeats and then correct the rhythm with electrical stimulation. However, they are not flexible enough and may restrict the heart's natural beating, damage soft tissue, cause temporary discomfort, and may cause complications such as swelling, perforation, blood clots, and infection.

After screening a variety of materials, the researchers finally chose graphene, a "miracle material" with excellent biocompatibility. Graphene has a super-strong, lightweight structure and high conductivity, and has potential applications in high-performance electronics, high-strength materials, and energy devices. The new soft, flexible graphene implant is not only unobtrusive, but fits directly into the heart tightly and seamlessly, providing more precise measurements.

Graphene exhibits record high magnetoresistance

According to a paper published in Nature, researchers at the University of Manchester in the United Kingdom report record high magnetoresistance in graphene under ambient conditions.

Materials that change electrical resistivity strongly when exposed to a magnetic field could find widespread use, such as the tiny magnetic sensors that are included in every car and every computer.

Such materials are rare, and the resistivity of most metals and semiconductors varies by only a fraction of a percent (usually less than one part in a million) at room temperature and in practically viable magnetic fields.

To observe a strong magnetoresistance response, researchers typically cool the material to the temperature of liquid helium, where electrons scatter less inside and can follow cyclotron orbits.

The University of Manchester research team found that graphene, which has been studied in detail over the past 20 years, exhibits a very strong response, with a reluctance of up to more than 100%. This is a record-breaking magnetoresistance among all known materials.

Talking about this latest discovery, Professor Andre Geim, the leader of the research and winner of the 2010 Nobel Prize in Physics, said: "People like me who are engaged in graphene research always feel that this physical gold mine is long overdue. But the material keeps showing us that we’re wrong.”

The researchers used high-quality graphene this time and tuned it to its intrinsic pristine state, which produced a fast-moving "Dirac fermion" plasma that, despite frequent scattering, exhibited surprisingly high mobility, which is the key indicator of super magnetoresistance.

In addition to the record-setting magnetoresistance, the researchers also found that at higher temperatures, neutral graphene becomes a so-called "strange metal," whose behavior is poorly understood and remains  mysteries being explored around the world.