A Soft Jelly-Like Implant May Offer a New Way to Tackle High Blood Pressure

A stitch-free soft implant lowered blood pressure in rats, suggesting a less invasive approach to treating hypertension while reducing injury to nearby tissue.

High blood pressure affects nearly half of adults in the United States and remains a major driver of heart disease. While medication and lifestyle changes can help, about one in 10 people with the condition has drug-resistant hypertension, making blood pressure control especially difficult.

“For many patients, even taking a combination of three to five medicines doesn’t alleviate their high blood pressure,” said Tao Zhou, the study’s corresponding author and the Wormley Family Early Career Assistant Professor of Engineering Science and Mechanics at Penn State. “In these cases, bioelectronic devices that use electrical signals to modulate the body’s natural response systems offer a promising form of alternative treatment.” Zhou is also affiliated with Penn State’s Center for Neural Engineering, Huck Institutes of the Life Sciences, and Materials Research Institute.

Zhou and his team created CaroFlex, a soft, stretchable, 3D-printed device that wraps around an artery and delivers mild electrical stimulation. In a rodent study, the device reduced blood pressure and caused far less damage to surrounding tissue, according to a paper published in Device.

Electrical pulses lower blood pressure in rats

The device taps into a blood-pressure control system already present in the body. Specialized nerve endings known as baroreceptors sense changes in how much artery walls stretch and activate the baroreceptor reflex, or baroreflex, which helps regulate blood pressure by influencing how tightly blood vessels constrict. Many of these receptors are concentrated in the carotid sinus, a small area near the point where the carotid artery branches.

This artery supplies oxygen-rich blood to the head and neck. Zhou explained that electrical stimulation at the carotid sinus can activate these receptors and trigger the reflex to lower blood pressure.

To test the approach in living animals, the researchers implanted CaroFlex at the carotid sinus in rats. Sensors tracked blood pressure during a 10-minute test period. Four of the five electrical frequencies they evaluated lowered blood pressure, with average readings dropping by more than 15%.

After two weeks, tissue examination showed no obvious damage or immune reaction where CaroFlex had been in contact with the animals.

Soft electrodes hold on without stitches

Several commercially available devices already use electrical stimulation to activate this reflex. The engineering challenge is maintaining contact with an artery that is constantly stretching and shrinking. Traditional devices are usually built from rigid metals and plastics, which do not match the mechanics of soft tissue well. “These devices are usually held in place with stitches,” Zhou said. “These stitches can cause damage to the devices, and more importantly, the tissues they’re integrated with over time, as arteries stretch and shrink to help move blood around the body.”

CaroFlex is made mainly from hydrogel, a soft, jelly-like material that better matches tissue flexibility. Conductive hydrogels form the electrodes that deliver stimulation, while adhesive hydrogels create a strong, nontoxic bond that lets the device attach to biological tissue without stitches. The team used 3D printing to combine these electrical and adhesive components.

In lab tests on tissue samples, the researchers evaluated whether the material could remain flexible while maintaining reliable attachment. CaroFlex stretched to more than twice its original length before breaking. Its adhesive film held firmly even when made from mixtures stored for six months. The team also compared CaroFlex with traditional platinum bioelectrodes, measuring conductivity by passing electrical currents through each material. CaroFlex stayed more closely attached to tissue and provided a more dependable electrical connection than the conventional electrodes, the researchers reported.

Human trials remain a future goal

With the device shown to work in living tissue and to be compatible with surrounding tissue, Zhou said the next step is to refine its performance and scale up the approach. The long-term goal is to move toward clinical trials and test it as a treatment for hypertension in humans.

“Our lab is actively leading several developments in 3D-printed bioelectronics for use across the body, which is exciting,” Zhou said. “This fabrication approach allows us to design, fabricate, and adapt bioelectronics for potential clinical trials and commercial distribution much more efficiently than traditional methods of manufacturing.”

Reference: “3D printable suture-free bioadhesive electronic interface for hypertension therapy” by Marzia Momin, Salahuddin Ahmed, Arafat Hossain, Jia Sun, Xinyi Wang, Basma AlMahmood, Jiashu Ren, Li-Pang Huang, Umar Farooq, John Bisognano and Tao Zhou, Device.
DOI: 10.1016/j.device.2026.101150

This work was supported by the National Institutes of Health and the U.S. National Science Foundation.