It's possible that a graphene "tattoo" could improve heart function.

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• graphene
• heartbeat
• electrodes
• pacemaker
• cardiovascula

Some tattoos are so beautiful that they make your heart skip a beat.

A graphene "tattoo" applied to the heart of a rat could improve the rhythm of a heart that beats too slowly. Scientists disclose their findings online on March 25 in Advanced Materials. The device, which functioned like a futuristic pacemaker, sent out electrical signals to keep the heart beating normally.

Igor Efimov, a cardiovascular engineer at Northwestern University in Chicago, predicts that a version of the electronic gadget suitable for use in human hearts might be available for testing within five years.

Efimov and his team have spent years developing body-integrated implanted devices. Combining the hardness of electronics with the pliability of living, sometimes pulsating, tissue is a major obstacle. Most modern pacemakers need the insertion of long cables with electrodes at the end into a vein within the heart. The wires flex around 100,000 times a day, once for each heartbeat. According to Efimov, if you bend the device enough, it will break. Using ultrathin materials that move with the heart is one option, much like how plastic wrap sticks to jiggling Jell-O.

Efimov found an interesting paper in 2021 about graphene devices that might be placed to the skin like temporary tattoos. Dmitry Kireev, a biomedical engineer at the University of Texas at Austin, says graphene is "atomically thin," making it superior to the metal components often used in electronics.

Caltech scientist Nai-Chang Yeh, who was not involved in the research, thinks that graphene, which consists of a single layer of carbon atoms arranged in a honeycomb pattern, is an attractive material for biomedical usage (SN: 3/14/14). "Graphene is very flexible, it's biocompatible, it's highly transparent, it's highly conductive, and it's mechanically strong," she explains.

However, this was Kireev's first time using graphene tattoos on cardiac muscle. Well, would you like to try?" Efimov approached him, asking. Certainly, we are able to lend a hand. The scientists collaborated to conduct tests of the devices on mouse hearts and in the bodies of living rats. According to their findings, the heart tattoo was able to regulate irregular heartbeats in the rats by delivering electrical pulses directly to the organ.

The tattoos are made of ultrathin polymer and elastic silicone, between which is layered graphene. Graphene is connected to power wires through gold tape, which then allows electricity to flow through the gadget.

According to Efimov, the tattoo of the future will be wireless and may use a tiny antenna to receive electrical signals from a device worn on the breast. Even smaller graphene electrodes, about the size of rice grains, could be put into heart muscle one day, as envisioned by Efimov. Such little devices could serve as pacemakers but without the bulky parts usually associated with them.

All of that may sound like science fiction, but according to Efimov, the technology is on the horizon. It's crucial that you work on it right now.