A new graphene-based ‘tattoo’ treats the heart condition cardiac arrhythmia with light. This is the first graphene-based cardiac implant to sense irregularities. The medical device also has the capability to stimulates the heart.
With cardiac arrhythmias, heart rhythm disorders occur when the heart beats either too quickly or too slowly. Medics often seek to treat arrhythmia with implantable pacemakers and defibrillators that detect abnormal heartbeats and then correct rhythm with electrical stimulation. There are downsides with conventional medical technology.
The development is a joint venture between Northwestern University and the University of Texas at Austin and the resultant device has the appearance to a child’s temporary tattoo. The invention delivers the thinnest known cardiac implant to date.
This means the new graphene tattoo functions like a classical pacemaker, although it has improved conformability for soft, moving tissues. This is connected to the flexibility of graphene as a component. A related feature of graphene renders the device transparent, allowing medics to record and stimulate the heart using optical light (which connects to the medical field of optocardiography).
The graphene implant is thinner than a single strand of hair. Despite this physical format the device functions as a pacemaker but without the need for the hard, rigid materials that associated with conventional medical devices. The downside of some devices is that they are mechanically incompatible with the human body. Furthermore, rigid interfaces with soft tissues, like the heart, can cause various complications.
Graphene consists of a single layer of carbon atoms arranged in a honeycomb lattice (it is an allotrope formed from a one-atom thick layer of graphite). As Digital Journal has previously reported, the material is extremely stable, flexible, highly conductive, and of particular interest for electronic applications.
The bio-compatible implant is sufficiently thin and flexible to conform to the heart’s delicate contours. At the same time, it is sufficiently robust as to withstand the dynamic motions of a beating heart.
Part of the study involved developing a new technique for encasing the graphene tattoo and adhering it to the surface of a beating heart. This required the use of an elastic silicone membrane plus gold tape to serve as an electrical interconnect between the graphene and the external electronics used to measure and stimulate the heart.
The new device has been tested on a small animal model. These trials were successful and the graphene tattoo sensed irregular heartbeats and delivered electrical stimulation to correct the rhythm.
The studies on rats demonstrate how the device can sense irregular heart rhythms and then deliver electrical stimulation through a series of pulses without constraining or altering the heart’s natural motions. The research appears in the journal Advanced Materials, titled: “Graphene biointerface for cardiac arrhythmia diagnosis and treatment.”
