Team develops injectable pacemaker for emergency situations

A new study by Swedish researchers shows that injecting a solution of nanoparticles around the heart can cause a temporary pacemaker to self-assemble and correct cardiac arrhythmia in emergency situations using an external energy source. After treatment, the electrode spontaneously disappears from the body. The study was conducted on animals and is published in the journal Nature Communications.

Arrhythmia occurs when the electrical signals in the heart are disrupted, causing it to beat too fast, too slow, or irregularly. Arrhythmia can often be treated with medication, but it is also possible to change the heart rhythm using electrical signals, such as a surgically implanted defibrillator or pacemaker. These types of interventions can be difficult in war zones, when hiking in the mountains, or in other environments where a defibrillator is not available or surgery is not possible.

“We have developed an injectable pacemaker for emergency situations, which consists of a syringe loaded with a solution of nanoparticles,” says Roger Olsson, professor of chemical biology and therapeutics at Lund University and professor of medicinal chemistry at the University of Gothenburg.

Nanoparticles are extremely small particles. Due to their size, they can be injected with a needle thinner than a human hair. When the solution comes into contact with tissues, a structure forms around the heart, consisting of a long chain of molecules, called a polymer, which conducts electricity. The injected electrode integrates with the body’s cells and facilitates ECG measurements, can regulate heartbeats and correct arrhythmia.

“If you connect a mobile phone to the injection site near the heart, you can temporarily stimulate the heart rate for up to five days,” says Umut Aydemir, a doctoral student and first author of the study.

Thanks to the close contact between the polymer and the heart tissue, the pacemaker can operate with low input power, which can come from portable devices. Most people carry their mobile phone everywhere, and using a cable attached to the skin at the injection point near the heart, the phone’s charges can be transferred to the conductive electrode in the body. Using an app on the phone, which the researchers now want to develop, the user can then regulate the arrhythmia before the person in question can go to hospital for further treatment.

So far, these experimental studies have been performed on small animals, zebrafish and chicken embryos, in line with the 3R principle of reducing mammalian testing. Now that the concept is optimized and shows great potential, the next step is to perform studies on larger animals, such as pigs, with a view to transposition to humans.

“The method is minimally invasive. In addition, the pacemaker spontaneously degrades and is eliminated from the body after treatment, so it does not need to be surgically removed,” concludes Martin Hjort, research associate in chemical biology and therapeutics at Lund University.