CUHK researchers, led by Professors Zhang Li, Philip Chiu Wai-yan, and Tony Chan Kai-fung, have developed wirelessly powered electronic stents for a non-invasive electrical stimulation therapy to treat gastric acid reflux. The research was published in Science Advances and will be featured in Nature Reviews Bioengineering’s April 2023 issue.

GERD is a persistent gastrointestinal disorder with widespread prevalence. Medication is necessary for about 8% of patients, but it can harm their physical and mental health. Surgical interventions such as Nissen fundoplication and magnetic augmentation are available but require laparoscopic surgery. Electrical stimulation of the lower oesophageal sphincter (LES) offers a promising solution but requires invasive surgery, which is risky.

Implantable electrical stimulation systems for GERD have significant surgical burdens and potential risks, making them difficult to implement. As GERD patients become more prevalent worldwide, there is a strong need for a less invasive electrical stimulation system that can reduce surgical risks and increase patient acceptance.

The research team has developed a wirelessly powered electronic stent (E-Stent) that provides a less invasive strategy for diagnosis and treatment in the gastrointestinal tract. The E-Stent uses a super elastic clinical oesophageal stent as the mechanical skeleton, a liquid metal antenna, and an intrinsically stretchable pulse generator. The liquid metal has a low melting temperature and high electrical conductivity, making it compliant with deformations in the oesophagus. With a wearable power transfer system, the elastic antenna can harvest sufficient energy for electrical stimulation therapy, even under compression of the oesophagus.

To improve design flexibility and speed up production, the research team utilised a laser engrafting machine for the batch fabrication of stretchable circuits. The circuit’s intrinsic stretchability and excellent mechanical properties enable it to provide stable biphasic current stimulation under various extreme deformations. The E-Stent not only overcomes the power bottleneck of bioelectronic implants but also has the potential for other non-invasive biomedical applications in organs with a natural orifice.

The Director of the Chow Yuk Ho Technology Centre for Innovative Medicine, CU Medicine stated that the team’s bioelectronic platform can regulate GERD by electrical stimulation. The researchers demonstrated the concept in pig models, showing that continuous electrical stimulation can increase the pressure on the lower oesophageal sphincter, which could potentially prevent gastric acid in a less invasive way. The team’s next step is to optimise and transform the prototypes into clinical products. They will continue their interdisciplinary collaboration to move forward with the work and help more people.

Professor Zhang Li from the Department of Mechanical and Automation Engineering collaborated with CU Medicine to develop the E-Stent platform and a transoral delivery strategy to overcome several challenges in mucosa-interfacing bioelectronics.

The team worked to address issues such as wirelessly powering bioelectronics inside the body, especially for high-power applications like electrical stimulation, and designing microneedle electrodes to safely and efficiently deliver electrical stimulation across the mucosa, which acts as a natural barrier protecting the GI tract.

Research Assistant Professor Tony Chan Kai-fung of the Chow Yuk Ho Technology Centre for Innovative Medicine expressed that digital medicine could have a transformative impact and demonstrates the clinical potential to integrate other functions. He suggested that pressure sensors and other bio-sensors could be integrated with the E-Stent for physiological assessment.

The data collected could be used for real-time optimisation of electrical stimulation and personalised treatment. Professor Chan also noted that the applications of the E-Stent platform are not limited to GERD but can be extended to other parts of the gastrointestinal tract and organs with natural orifices.

Currently, the research team is collaborating to add new features to the E-Stent for other applications in the gastrointestinal tract and conducting further preclinical and clinical evaluations. The team aims to develop a non-invasive platform that provides efficient and safe options for personalised treatments and physiological assessments with various functions of high clinical value. The team envisions that the E-Stent will have a promising future as a highly useful technology.

Malignant cancers originating from different organs frequently metastasize to the lungs. Traditional surgical removal of lung metastases can result in significant surgical trauma and the unwanted removal of adjacent healthy lung tissue. The Faculty of Medicine at the Chinese University of Hong Kong (CU Medicine) has carried out the world’s first bronchoscopic microwave ablation of lung metastases, assisted by robotics.

Since October 2022, they have successfully treated three patients with a total of six lung metastases using this innovative technique. This procedure allows doctors to accurately access peripheral areas of the lung and perform non-invasive, lung-sparing microwave ablation of lung metastases. It is currently in clinical trials, with a goal of enrolling up to 145 patients worldwide.

Robotic bronchoscopic microwave ablation protects lung function and avoids surgery trauma

Patients with lung metastases may have undergone prior surgery or be receiving chemotherapy for their advanced-stage cancer. They may already be physically and mentally weakened from the various treatments they are receiving. The primary treatment for lung metastases is surgical resection, but this can lead to trauma during access and the removal of healthy lung tissue.

For precise delivery of a small catheter into the small airways to reach lung metastases and perform non-invasive transbronchial microwave ablation, an advanced navigation bronchoscopy platform is required. This novel form of treatment is unique as it does not require surgical wounds, resulting in minimal pain and blood loss. Moreover, it is lung parenchymal sparing, meaning it does not involve the removal of healthy lung tissue. Microwave energy is used during the procedure to heat and destroy cancer cells.

CU Medicine has been at the forefront of using bronchoscopy with navigational capabilities to diagnose and treat peripheral lung tumours. With the latest robotic-assisted bronchoscopy platform, there are added advantages over previous systems, including improved navigation accuracy to lung lesions and greater procedural stability. This innovative approach of using robotic bronchoscopy for transbronchial microwave ablation of lung metastases can be a significant change for those with advanced-stage metastatic lung cancer.

According to Dr Rainbow Lau Wing-hung, a Clinical Assistant Professor (honorary) in the Division of Cardiothoracic Surgery, Department of Surgery at CU Medicine, bronchoscopy is an endoscopic procedure commonly carried out by doctors specializing in lung disorders.

The new robotic-assisted bronchoscopy employs real-time optical imaging and electromagnetic positioning to navigate the complex human airways. The operator can use a remote console to accurately drive the device to the desired location within the lung, which is linked with the robotic arms and bronchoscope. The advanced robotic mechanism within the bronchoscope ensures stability while deploying the microwave ablation catheter, improving the accuracy and efficiency of the ablation procedure.

CU Medicine: pioneering thoracic surgical treatments in the Asia-Pacific region

CU Medicine’s thoracic surgical team has been at the forefront of using advanced minimally invasive techniques with the latest technologies. These include single port video-assisted thoracoscopic surgery for major lung resection, as well as image-guided surgery and navigation bronchoscopy in the Hybrid Operating Room.

Professor Calvin Ng Sze-hang, a Professor in the Division of Cardiothoracic Surgery, Department of Surgery at CU Medicine, expressed his excitement about performing the world’s first robotic-assisted bronchoscopy microwave ablation of lung metastases.

By combining the advantages of precise airway navigation with robotic bronchoscopy and CU Medicine’s world-leading experience in transbronchial microwave ablation of lung tumours, patients with lung metastases now have an additional non-invasive treatment option.

Patients with advanced cancer often have multiple lung metastases spread throughout both lungs. Conventional surgical resection involves bilateral surgical incisions and the removal of multiple lung tissue wedges, which can have a significant impact on the patient’s lung function and may delay chemotherapy administration as they recover from surgery.

The novel approach of using robotic bronchoscopic microwave ablation allows for the treatment of multiple bilateral lung metastases without any incisions or lung resection. This method has almost no impact on the patient’s lung function or quality of life.