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Liu W, Choi SJ, George D, Li L, Zhong Z, Zhang R, Choi SY, Selaru FM, Gracias DH. Untethered shape-changing devices in the gastrointestinal tract. Expert Opin Drug Deliv 2023; 20:1801-1822. [PMID: 38044866 PMCID: PMC10872387 DOI: 10.1080/17425247.2023.2291450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 12/01/2023] [Indexed: 12/05/2023]
Abstract
INTRODUCTION Advances in microfabrication, automation, and computer engineering seek to revolutionize small-scale devices and machines. Emerging trends in medicine point to smart devices that emulate the motility, biosensing abilities, and intelligence of cells and pathogens that inhabit the human body. Two important characteristics of smart medical devices are the capability to be deployed in small conduits, which necessitates being untethered, and the capacity to perform mechanized functions, which requires autonomous shape-changing. AREAS COVERED We motivate the need for untethered shape-changing devices in the gastrointestinal tract for drug delivery, diagnosis, and targeted treatment. We survey existing structures and devices designed and utilized across length scales from the macro to the sub-millimeter. These devices range from triggerable pre-stressed thin film microgrippers and spring-loaded devices to shape-memory and differentially swelling structures. EXPERT OPINION Recent studies demonstrate that when fully enabled, tether-free and shape-changing devices, especially at sub-mm scales, could significantly advance the diagnosis and treatment of GI diseases ranging from cancer and inflammatory bowel disease (IBD) to irritable bowel syndrome (IBS) by improving treatment efficacy, reducing costs, and increasing medication compliance. We discuss the challenges and possibilities associated with ensuring safe, reliable, and autonomous operation of these smart devices.
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Affiliation(s)
- Wangqu Liu
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Soo Jin Choi
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Derosh George
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Ling Li
- Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Zijian Zhong
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Ruili Zhang
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Si Young Choi
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Florin M. Selaru
- Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - David H. Gracias
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Laboratory for Computational Sensing and Robotics (LCSR), Johns Hopkins University, Baltimore, MD 21218, USA
- Sidney Kimmel Comprehensive Cancer Center (SKCCC), Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Center for MicroPhysiological Systems (MPS), Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
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Wu L, Lu K. Experimental investigation of a new type of driving concept for capsule robot. INTEL SERV ROBOT 2022. [DOI: 10.1007/s11370-022-00443-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Cortegoso Valdivia P, Robertson AR, De Boer NKH, Marlicz W, Koulaouzidis A. An Overview of Robotic Capsules for Drug Delivery to the Gastrointestinal Tract. J Clin Med 2021; 10:5791. [PMID: 34945087 PMCID: PMC8707371 DOI: 10.3390/jcm10245791] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/05/2021] [Accepted: 12/08/2021] [Indexed: 12/19/2022] Open
Abstract
The introduction of capsule endoscopy two decades ago marked the beginning of the "small bowel revolution". Since then, the rapid evolution of microtechnology has allowed the development of drug delivery systems (DDS) designed to address some of the needs that are not met by standard drug delivery. To overcome the complex anatomy and physiology of the gastrointestinal (GI) tract, several DDS have been developed, including many prototypes being designed, built and eventually produced with ingenious drug-release mechanisms and anchoring systems allowing targeted therapy. This review highlights the currently available systems for drug delivery in the GI tract and discusses the needs, limitations, and future considerations of these technologies.
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Affiliation(s)
- Pablo Cortegoso Valdivia
- Gastroenterology and Endoscopy Unit, University Hospital of Parma, University of Parma, 43121 Parma, Italy;
| | | | - Nanne K. H. De Boer
- Department of Gastroenterology and Hepatology, Amsterdam University Medical Centre, AGEM Research Institute, VU University, 1105 AZ Amsterdam, The Netherlands;
| | - Wojciech Marlicz
- Department of Gastroenterology, Pomeranian Medical University, 70-204 Szczecin, Poland;
| | - Anastasios Koulaouzidis
- Department of Public Health and Social Medicine, Pomeranian Medical University, 70-204 Szczecin, Poland
- AJM Med-i-Caps Ltd., Nicosia 2020, Cyprus
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Smart pills for gastrointestinal diagnostics and therapy. Adv Drug Deliv Rev 2021; 177:113931. [PMID: 34416311 DOI: 10.1016/j.addr.2021.113931] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 08/03/2021] [Accepted: 08/13/2021] [Indexed: 12/13/2022]
Abstract
Ingestible smart pills have the potential to be a powerful clinical tool in the diagnosis and treatment of gastrointestinal disease. Though examples of this technology, such as capsule endoscopy, have been successfully translated from the lab into clinically used products, there are still numerous challenges that need to be overcome. This review gives an overview of the research being done in the area of ingestible smart pills and reports on the technical challenges in this field.
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Abstract
In order to improve the reliability, safety and whole digestive applicability of the gastrointestinal microrobot (GMR), a novel inchworm-like GMR is proposed in this paper. The expanding mechanism of the robot adopts an overlapping expanding arm structure. This structure increases the variable diameter ratio (ratio of fully expanded diameter to fully folded diameter) of the robot to 3.3, making the robot more applicable to the intestines in various parts of the human body. The mechanical model of the expanding arm is established, and the expanding force at different expanding radii is obtained. And then the expanding force is tested by a force test platform. The force test results: the maximum expanding force is 6.5 N, and the minimum expanding force is 1.3 N. The trend of the experimental and theoretical values is the same, and the experimental value is less than the theoretical value. A position limiting device based on Hall sensor is designed, which detects whether the mechanism reaches the limit position by non-contact method. This device alleviates the problem of sharp voltage drop caused by motor stall and improves the stability of the control circuit. The results of the Hall-type position limiting device (HPLD) testing show that the working currents of the expanding mechanism and the telescoping mechanism with HPLD are respectively 0.066A and 0.110A, and the robot control circuit works stably. Finally, the robot is tested in the intestine of the living pig, and the safety and reliability of the robot are verified. However, due to the decrease of the efficiency of wireless power transmission in vivo experiments and the change of the position of the receiving coil relative to the transmitting coil, sometimes the power supply is insufficient.
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Affiliation(s)
- Wei Wang
- Shanghai Jiao Tong University, Shanghai, China
| | | | - Ding Han
- Shanghai Jiao Tong University, Shanghai, China
| | - Yicun Meng
- Shanghai Jiao Tong University, Shanghai, China
| | - Pengxian Pu
- Shanghai Jiao Tong University, Shanghai, China
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Abstract
Wireless capsule endoscopy (WCE) is noninvasive, painless, and riskless on detection for gastrointestinal disease. It attracts increasing attention. Wireless power transfer (WPT) technology is utilized to supply power for WCE. Receiving coil (RC) of WPT is capsulated into WCE. Its position and direction change all through gastrointestinal tract. Transmitting coil (TC) is worn by the patient. So the mutual inductance varies all the time. It should be studied to ensure sufficient receiving power. However, existing analytical methods do not reach satisfactory accuracy. They can only solve simple cases with positional misalignment. Numerical simulation models are time-consuming. Furthermore, an entirely new simulation must be repeated when any change in alignment occurs. Thus, based on geometry and misalignment of RC and TC, a model for mutual inductance is proposed. Compared with analytical methods, it is applicable to not only circular and rectangular RC, but also the elliptic, with directional misalignment. It costs below 0.1% of computational time of the simulation for the same accuracy. Moreover, any change in misalignment is easily handled by a simple change of parameter in the model. It reaches a tradeoff between computational accuracy and time. Receiving power is evaluated rapidly and accurately with proposed model.
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Affiliation(s)
- Shuai Kuang
- Department of Precise Medical Engineering and Intelligent Electronic Microsystems, School of Electronics Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, China.
| | - Guozheng Yan
- Department of Precise Medical Engineering and Intelligent Electronic Microsystems, School of Electronics Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, China
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Abstract
Untethered miniature robots have significant poten-tial and promise in diverse minimally invasive medical applications inside the human body. For drug delivery and physical contra-ception applications inside tubular structures, it is desirable to have a miniature anchoring robot with self-locking mechanism at a target tubular region. Moreover, the behavior of this robot should be tracked and feedback-controlled by a medical imaging-based system. While such a system is unavailable, we report a reversible untethered anchoring robot design based on remote magnetic actuation. The current robot prototype's dimension is 7.5 mm in diameter, 17.8 mm in length, and made of soft polyurethane elastomer, photopolymer, and two tiny permanent magnets. Its relaxation and anchoring states can be maintained in a stable manner without supplying any control and actuation input. To control the robot's locomotion, we implement a two-dimensional (2D) ultrasound imaging-based tracking and control system, which automatically sweeps locally and updates the robot's position. With such a system, we demonstrate that the robot can be controlled to follow a pre-defined 1D path with the maximal position error of 0.53 ± 0.05 mm inside a tubular phantom, where the reversible anchoring could be achieved under the monitoring of ultrasound imaging.
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Affiliation(s)
- Tianlu Wang
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Wenqi Hu
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Ziyu Ren
- Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
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Wang W, Yan G, Wang Z, Jiang P, Meng Y, Chen F, Xue R. A Novel Expanding Mechanism of Gastrointestinal Microrobot: Design, Analysis and Optimization. MICROMACHINES 2019; 10:E724. [PMID: 31717762 PMCID: PMC6915638 DOI: 10.3390/mi10110724] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 12/11/2022]
Abstract
In order to make the gastrointestinal microrobot (GMR) expand and anchor in the gastrointestinal tract reliably, a novel expanding mechanism of the GMR is proposed in this paper. The overlapping expanding arm is designed to be used to increase the variable diameter ratio (ratio of fully expanded diameter to fully folded diameter) to 3.3, which makes the robot more adaptable to the intestinal tract of different sections of the human body. The double-layer structure of the expanding arm increases the contact area with the intestine, reducing the risk of intestinal damage. The kinematics and mechanical model of the expanding arm are established, and the rigid velocity, rigid acceleration, and expanding force of the expanding arm are analyzed. The elastodynamics model of the expanding arm is established. Through the finite element analysis (FEA), the velocity, acceleration, and the value and distribution of the stress of the expanding arm under elastic deformation are obtained. Based on the elastodynamics analysis, the structure of the expanding arm is optimized. By the structure optimization, the thickness of the expanding mechanism is reduced by 0.4mm, the weight is reduced by 31%, and the stress distribution is more uniform. Through the mechanical test, the minimum expanding force of the expanding mechanism is 1.3 N and the maximum expanding force is 6.5 N. Finally, the robot is tested in the rigid pipeline and the isolated intestine to verify the reliability and safety of the expanding mechanism.
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Affiliation(s)
- Wei Wang
- School of electronic information and electrical engineering, Shanghai Jiao Tong University, Shanghai 200240, China; (W.W.); (Z.W.); (P.J.); (Y.M.); (F.C.); (R.X.)
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Guozheng Yan
- School of electronic information and electrical engineering, Shanghai Jiao Tong University, Shanghai 200240, China; (W.W.); (Z.W.); (P.J.); (Y.M.); (F.C.); (R.X.)
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhiwu Wang
- School of electronic information and electrical engineering, Shanghai Jiao Tong University, Shanghai 200240, China; (W.W.); (Z.W.); (P.J.); (Y.M.); (F.C.); (R.X.)
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Pingping Jiang
- School of electronic information and electrical engineering, Shanghai Jiao Tong University, Shanghai 200240, China; (W.W.); (Z.W.); (P.J.); (Y.M.); (F.C.); (R.X.)
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yicun Meng
- School of electronic information and electrical engineering, Shanghai Jiao Tong University, Shanghai 200240, China; (W.W.); (Z.W.); (P.J.); (Y.M.); (F.C.); (R.X.)
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Fanji Chen
- School of electronic information and electrical engineering, Shanghai Jiao Tong University, Shanghai 200240, China; (W.W.); (Z.W.); (P.J.); (Y.M.); (F.C.); (R.X.)
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Rongrong Xue
- School of electronic information and electrical engineering, Shanghai Jiao Tong University, Shanghai 200240, China; (W.W.); (Z.W.); (P.J.); (Y.M.); (F.C.); (R.X.)
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai 200240, China
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