MIT researchers have developed a noninvasive, surgery-free alternative to standard cardiac implants: a wearable ultrasound pacemaker sticker.

Interestingly, the new device is simply a wearable sticker applied to the chest.

It uses focused ultrasound waves to dictate the rhythm of a beating heart. The technology pairs an external acoustic sticker with a cutting-edge field of science known as “sonogenetics.” In this field, the genetically engineered cells respond directly to sound.

“We believe you could one day have stickers on the body that could do long-term imaging deep in the body and also do stimulation for therapeutic effects, in a noninvasive closed-loop way,” said Xuanhe Zhao, professor of mechanical engineering and of civil and environmental engineering at MIT.

Shows promise in testing

The standard pacemakers mostly use direct electrical impulses. It saves millions of lives, but requires invasive surgery and direct contact with cardiac tissue. 

Scientists have known that ultrasound can safely penetrate the body and influence tissue, but past attempts to use it for cardiac pacing were far too weak and inconsistent to be viable.

To solve this, the research team turned to sonogenetics.

First, specialized gene therapy was used to modify heart cells, introducing custom ion channels that open up when hit by specific acoustic frequencies. When the external ultrasound sticker emits a pulse, these modified channels instantly open, allowing a rush of calcium to enter the cell. That calcium influx is the exact chemical green light a heart cell needs to squeeze and beat.

“These channels can now ‘hear’ ultrasound better and can open to let calcium in, which is what directly activates the cell and causes it to beat,” explained Chen Gong, the paper’s first author. 

The engineers packed this acoustic technology into a postage-stamp-sized device embedded with tiny ultrasound transducers. Made from a highly refined hydrogel, the sticker clings tightly to human skin while allowing ultrasound waves to pass through with perfect clarity.

The results in the lab were immediate.

When tested on engineered human cardiac cells, the cells immediately fell into lockstep with the ultrasound’s rhythm. In live tests on rats experiencing dangerous arrhythmias, the miniature sticker rapidly steadied their irregular heartbeats. It brought slow, faltering hearts back up to a healthy, vibrant pace.

Two-step approach

How would this look for actual human patients? The team envisions a straightforward, two-step clinical approach.

A patient would first receive a one-time injection. This gene therapy — modeled after existing FDA-approved treatments for disorders like sickle cell disease — would permanently prime the heart cells to listen to acoustic signals. From there, the patient simply wears the stamp-sized sticker, which connects to a pocket-sized battery pack.

“We think this step would be clinically translatable as a form of gene therapy that could enable noninvasive pacemakers,” Gong stated.

This same MIT group previously invented an ultrasound sticker that can image deep internal organs; they are actively merging the two projects. The ultimate goal is a single, smart sticker that simultaneously monitors your heart in real time and steps in with acoustic pulses the second an arrhythmia is detected.

If validated for human use, this technology will redefine medicine as a wireless, wearable, and skin-deep experience.

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