Penn State’s 3D printed hydrogel implant cuts blood pressure by 15% in trials
Stitch-free CaroFlex device uses conductive hydrogels and electrical stimulation as a drug-free approach to hypertension
Researchers at Penn State University have developed a 3D printed bioelectronic implant that wraps around the carotid artery and delivers low-frequency electrical pulses to reduce blood pressure, and all without sutures or pharmaceutical intervention. The device, named CaroFlex, was constructed from conductive hydrogels.
Conventional implantable bioelectronics currently rely on rigid metals and plastics, but these struggle to accommodate the constant expansion and contraction of blood vessels. That mechanical mismatch can lead to a degradation of the device’s contact over time and cause surrounding tissue damage. CaroFlex claims to address this by incorporating an adhesive hydrogel layer that bonds directly to the artery wall.
“These devices are usually held in place with stitches,” said Tao Zhou, Assistant Professor of Engineering Science and Mechanics at Penn State. “These stitches can cause damage to the tissues they’re integrated with over time.”
CaroFlex targets the body’s baroreflex system — a mechanism that regulates blood pressure through pressure-sensitive nerve endings in the carotid sinus. The implant delivers electrical pulses to those receptors, which signal the brain to adjust heart rate and vascular tension.
Before animal testing, the research team evaluated the device’s physical and electrical properties in laboratory conditions. The hydrogel structure stretched to more than twice its original length before failure, and the adhesive layer maintained stable performance after six months in storage.
In rat trials, four of five electrical stimulation settings reduced blood pressure by more than 15% on average. Tissue examination two weeks post-implantation showed minimal inflammation or immune response, and when compared against conventional platinum-based electrodes, CaroFlex demonstrated more consistent tissue contact and steadier electrical output.
“For many patients, even taking a combination of three to five medicines doesn’t alleviate their high blood pressure,” Zhou said. He added that bioelectronic therapies may offer another path for patients whose hypertension remains uncontrolled despite standard treatment.
The team stated that 3D printing could help speed the development of personalized bioelectronic implants for cardiovascular and other chronic conditions. Further work is planned to refine the device before advancing to larger animal studies.
Zhou recently led the development of a method for 3D printing soft brain electrodes shaped to match the unique surface geometry of individual patients, with the goal of improving neural monitoring for neurodegenerative diseases.
