Graphene's Heartbeat: How Ultra-Thin Sensors Could Transform Cardiac Care

When Hongyan Gao first approached Zhien (Abigail) Wang about collaborating to graft graphene into lab-grown cardiac microtissue (CMT), she was a little shocked. Abigail, who is pursuing her doctorate at MIT, has years of experience researching graphene and studying various ways to synthesize it to meet specific conditions. However, she had never considered its biomedical applications.

It is known through previous experiments that graphene has several unique characteristics. First, graphene can detect changes in electrical conductivity, dubbed the field effect. Second, graphene can detect when mechanical strain is applied (the piezoresistive effect). Graphene is like a smart fabric that can both sense your touch and feel your stretch; it can detect changes electrically when you press it, like a touchscreen, and mechanically when you pull on it, like a stretchable sensor, making it incredibly versatile for advanced sensing applications.

The dual-sensing nature of graphene turned out to be a great fit for Hongyan's project, which seeks to improve how we detect and monitor cardiac disease. Cardiovascular disease, including stroke, is the leading cause of illness and death in the United States. But the heart, an extraordinary muscle that tirelessly pumps life-sustaining blood throughout our bodies, is tricky. You cannot just attach a probe to a beating heart. Sensing data from the heart is a complicated process. The action of your heart consists of electrical signals sent by special pacemaker cells that generate a mechanical movement. Graphene's ability to sense both electrical action and mechanical movement at the same time fits perfectly with the heart's dual nature, termed the excitation-contraction (EC) coupling by the authors.

Graphene is naturally incredibly thin, being tens of thousands of times smaller than a human cell. It's like comparing a grain of sand to a basketball court. This makes the graphene-integrated mesh electronics as soft as heart tissue, allowing it to gently integrate with small heart tissues. Moreover, this device is durable enough to handle stretching, aggregation, and folding, all of which occur as the heart pumps. It can then be smoothly incorporated into three-dimensional heart tissue to accurately measure signals at the cellular level in a localized area.

The team recently published their work, demonstrating that their graphene-integrated mesh can effectively monitor excitation-contraction dynamics in cardiac microtissues.  Read more in the Nature Communications article: https://www.nature.com/articles/s41467-024-46636-7

Credit: Zhien (Abigail) Wang (MIT), Hongyan Gao (Umass Amherst)