Targeted Drug Delivery Using Self-Unrolling Sheets in Magnetically Actuated Capsules
Targeted Drug Delivery Using Self-Unrolling Sheets in Magnetically Actuated Capsules
Background
Gastrointestinal (GI) diseases, such as inflammatory bowel disease, GI bleeding, and cancer, are significant global health issues. Traditional treatment methods, such as endoscopy and oral medications, though effective to some extent, have many limitations. For example, endoscopy relies heavily on the operator’s skill and is challenging to cover the entire GI tract in a single session. Oral medications face issues like drug degradation and limited absorption in the GI tract.
To address these challenges, capsule endoscopy and drug delivery systems have gained widespread attention in recent years. However, existing capsule systems still fall short in targeted treatment of multiple lesions and active mobility capabilities. In their 2025 study published in the journal Device, Lee et al. proposed a novel magnetically actuated capsule system capable of delivering therapeutic sheets (TheraS) to specific lesions in the GI tract, with precise navigation through real-time imaging.
Research Team and Publication Information
The study was conducted by Jihun Lee, Sanghyeon Park, Deockhee Yoon, and Chandran Murugan from the Department of Robotics and Mechatronics Engineering at Daegu Gyeongbuk Institute of Science and Technology (DGIST), along with Seungmin Bang from Yonsei University College of Medicine and Sukho Park from DGIST. The research was published on April 18, 2025, in the journal Device.
Research Process and Experimental Design
1. Preparation and Structure of TheraS
TheraS consists of three layers: the unrolling layer, the guard layer, and the therapeutic layer. The unrolling and guard layers are made of polyethylene glycol dimethacrylate (PEGDMA) and triethylene glycol dimethacrylate (TEGDMA), respectively, while the therapeutic layer contains magnetic nanoparticles (MNPs) and the anticancer drug doxorubicin (DOX). The fabrication of TheraS involves UV curing, freeze-drying, and heat treatment. Finally, TheraS is rolled into a cylindrical shape and loaded into four channels of the magnetically actuated capsule.
2. Design of the Magnetically Actuated Capsule
The design of the magnetically actuated capsule is based on a previously developed 6-channel microbiota sampling capsule, with slight modifications to accommodate the loading and release of TheraS. The capsule consists of permanent magnets, a pushing bar, channels, and a real-time camera. Through an external magnetic field, the capsule can actively move within the GI tract and release TheraS to target lesions via the pushing bar.
3. Unrolling and Drug Release of TheraS
TheraS automatically unrolls upon contact with GI fluids and adheres tightly to the GI surface. The application of an alternating magnetic field (AMF) increases the temperature of TheraS, promoting drug release and localized hyperthermia. Through the real-time camera, operators can monitor the treatment process, ensuring precise drug delivery.
Key Findings
1. Unrolling Performance of TheraS
Experimental results show that TheraS can effectively unroll in various GI environments with different pH levels. For example, in the small intestine (pH 6.8) and stomach (pH 2.0), TheraS fully unrolls and adheres closely to the surface. Additionally, the adhesive force of TheraS to the GI tract is significantly higher than that of traditional gelatin sheets, indicating its superior adhesive performance in practical applications.
2. Drug Release and Hyperthermia Effects
The application of AMF significantly enhances the drug release efficiency of TheraS. Experiments show that under AMF, both the drug release area and the amount of Dox released from TheraS on the small intestine surface increase significantly. Moreover, the temperature of TheraS rises to 42–59°C under AMF, effectively inducing tumor cell apoptosis and localized hyperthermia.
3. Operational Performance of the Magnetically Actuated Capsule
The magnetically actuated capsule can precisely navigate to target lesions in the GI tract via an external magnetic field and successfully release TheraS. Experiments demonstrate that both the movement of the capsule in the GI tract and the release of TheraS can be monitored in real-time with the integrated camera, ensuring treatment precision.
Significance and Application Value
The proposed magnetically actuated capsule system offers a novel minimally invasive solution for treating GI diseases. Through the precise delivery of TheraS and real-time monitoring, this system can effectively treat multiple GI lesions, improving the efficiency and safety of targeted therapy. Future optimization and clinical validation of this technology hold promise for further breakthroughs in GI disease treatment.
Highlights of the Research
- Multi-Lesion Targeted Therapy: The capsule system can treat multiple GI lesions in a single session, enhancing treatment efficiency.
- Real-Time Monitoring and Precise Navigation: The integrated camera allows operators to monitor the drug delivery process in real-time, ensuring precision.
- Self-Unrolling Sheet Design: TheraS can automatically unroll and adhere tightly to lesion surfaces in the GI tract, ensuring effective drug release and localized hyperthermia.
Future Prospects
Although the study has made significant progress in targeted drug delivery, further optimizations are needed. For instance, the capsule’s localization technology within the GI tract can be improved to enhance navigation accuracy. Additionally, the biocompatibility of the capsule needs further enhancement to ensure its safety in long-term use. Future research could explore integrating wireless functionality to further increase its clinical application value.
Conclusion
The magnetically actuated capsule system developed by Lee et al. provides an innovative solution for targeted therapy of GI diseases. Through the precise delivery of TheraS and real-time monitoring, this system has the potential to become an effective tool for treating various GI conditions, offering significant scientific and clinical value.