Wirelessly powered e-stent: A promising, noninvasive GERD treatment

Researchers from the Chinese University of Hong Kong (CUHK) have developed a wireless, battery-free, deformable electronic stent (e-stent) for treatment of gastroesophageal reflux disease (GERD), eliminating the need for invasive surgery.

GERD is a chronic relapsing gastrointestinal (GI) disorder characterized by reflux of gastric content into the oesophagus due to transient lower oesophageal sphincter (LES) relaxation. Although effective for symptom control, both magnetic sphincter augmentation and Nissen fundoplication require laparoscopic surgery and may lead to persistent dysphagia. Electrical stimulation therapy (EST) is an attractive treatment option not associated with dysphagia, but both the LES stimulator implant procedure and battery replacement require invasive surgery. [Sci Adv 2023;doi:0.1126/sciadv.ade8622; Int J Pediatr Res 2019;5:054; Surg Endosc 2013;27:1083-1092]

“With the increasing prevalence of GERD worldwide, there is a strong demand for developing a less invasive EST system to minimize risks associated with open surgery,” wrote the researchers. The team thus developed a wirelessly powered e-stent consisting of a super elastic oesophageal stent as the mechanical skeleton, a liquid metal antenna, and an intrinsically stretchable pulse generator. Notably, the GI tract allows noninvasive delivery of the e-stent to the LES zone, providing a bioelectronic platform to control LES relaxation by electronic stimulation.

“The liquid metal has a low melting point of 15.4^oC and high electrical conductivity, making it compliant with deformation in the oesophagus. Coupled with a wearable power transfer system, the elastic antenna can harvest sufficient energy for EST through deep tissue, even under compression of the oesophagus,” noted Professor Zhang Li of the Mechanical and Automation Engineering, CUHK. “The intrinsic stretchability and excellent mechanical properties of the e-stent allow 150 percent axial elongation and 50 percent radial compression, and enable the circuit to provide stable biphasic current stimulation in the dynamic environment of the oesophagus.”

“We demonstrated that electronic stimulation delivered by the e-stent significantly increased LES pressure [p=0.0172] in pig models, suggesting that the e-stent could be a promising noninvasive solution for effective control of GERD symptoms,” shared Professor Philip Chiu of the Chow Yuk Ho Technology Centre for Innovative Medicine, CUHK.

The team’s next step is to optimize and transform the lab-made prototypes into clinical products. To accelerate production, the researchers utilized a laser engrafting machine for batch fabrication of stretchable circuits. Moreover, pressure sensor and other biosensors could be integrated with the e-stent for physiological assessment in the future. “The data collected could be used for real-time optimization of electrical stimulation,” noted Professor Tong Chan of the Chow Yuk Ho Technology Centre for Innovative Medicine, CUHK.

“Applications of the e-stent platform are not limited to GERD. It can also be used for other parts of the GI tract and organs with natural orifices,” Chan remarked. The team envisions that the e-stent could be a promising noninvasive platform for physiological assessment, personalized treatment, and other diverse functions with high clinical value.