Recently, active research has been conducted on the therapeutic functions of capsule endoscopes. Here, we propose an active capsule system that captures images of the interior of the gastrointestinal tract (GI) and actively delivers therapeutic patches. The active capsule system mainly comprises therapeutic patches, an active capsule equipped with a camera, and a robot-assisted magnetic actuator. The active capsule moves inside the GI tract via a magnetic actuator using a robot, captures pictures of the GI tract in actual time, and performs hemostatic treatment by delivering therapeutic patches to the target lesions. First, the fundamental performance of the active capsule system was verified via a hemostatic performance test of the therapeutic patch, patch contamination prevention test of the active capsule, and basic actuation test of the capsule. Second, multiple therapeutic patches were delivered to the gastric surface in an ex vivo test using an active capsule system. Finally, as a preclinical test, it was confirmed that the GI tract examination and the therapeutic patches delivery were possible using the active capsule system through an animal test using a porcine. Consequently, the proposed active capsule system represents a new paradigm for capsule endoscopy with multiple therapeutic patch delivery capabilities.

Soft continuum robots have been widely used as guide wires or catheters for minimally invasive surgery (MIS), and the miniaturization and dexterity are very important characteristics of soft continuum robots. As a representative actuation method for soft continuum robots, the steering using an external magnetic field has been actively studied. The magnetic actuation method is appropriate for the miniaturization of soft continuum robots but shows limitations in implementing high dexterity. To achieve miniaturization and high dexterity, this paper proposes a magnetically steerable asymmetric magnetized soft continuum robot (AMSCR). The proposed AMSCR includes an active steering part (ASP) of a thin PDMS cylinder in which NdFeB powder is uniformly dispersed and magnetized asymmetrically to the longitudinal direction. Therefore, compared to the conventional symmetric magnetized soft continuum robot (SMSCR), the proposed AMSCR has a larger steering range and high dexterity. Through various experiments, simulations, and phantom experiments using the proposed AMSCR, we analyzed its characteristics, verified its enhanced steering range, and demonstrated the applicability to the surgeries requiring high dexterity in the eye or cerebrovascular.

This study proposes a prototype of bacteria-based microrobots using chitosan-coated liposomes attached to a Salmonella enteritidis bacterial strain. The attachment of the liposome and the bacteria is performed by interaction between the positive charge surface of the liposomes and the gram-negative bacteria. The liposomes are fabricated using hydration method to obtain the average diameter of 10 um and they are coated with chitosan. The chitosan coating is shown to have effect on motility of the microrobots. First, the bacteria cannot attach to chitosan-uncoated liposomes, but they can easily adhere to the chitosan-coated liposomes. Second, when the concentration of chitosan increases from 0.1% to 0.5%, average velocity of the microrobots increases from 1.20±0.12 um/s to 3.25±0.35 um/s. However, when chitosan concentration increases to 1% the average velocity of the microrobots slightly decreases from 3.25±0.35 um/s to 3.17±0.33 um/s, respectively. The study suggests that using chitosan coating can be a potential method for further development of therapeutic bacteria-based liposomal microrobots.

Various types of actuation methods for intravascular locomotive microrobot have been proposed and demonstrated. Among the actuation methods, electromagnetic based actuation (EMA) was considered as a promising mechanism. In generally, planar EMA systems for 2 dimensional movement of the microrobot were proposed and demonstrated. In this paper, we present 3 dimensional (D) EMA systems for the 3D space locomotion of the microrobot. The proposed system consists of a coil system and a robotic actuation system. The coil system has a pair of Helmholtz coils and a pair of Maxwell coils, and the robotic actuation system has a serial robot structure with roll-pitch-roll rotational axes which can rotate about three orthogonal axes (X, Y and Z). Finally, through experiments, we can demonstrate 3D movement of the microrobot by using the proposed EMA system. The proposed EMA system can be utilized for the 3D actuation of the intravascular microrobot.

This paper introduces biohybrid microsystems actuated by cardiomyocytes, such as microcantilever, microrobot, and micropump. The microfabicated biohybrid microcantilever can measure the contractile force of self-organized cardiomyocytes. The microcantilever is made of a biocompatible PDMS substrate, using a simple microfabrication technique and a specially designed 3D micromolding aligner. The contractile force of the cardiomyocytes makes a bending displacement of the microcantilever. Conversely, from the displacement, we can estimate the contractile of the cardiomyocytes on the microcantilever. The bending motion of the microcantilever can be applied as a biohybrid actuator of microrobot. We have developed a novel method to fabricate a crab-like microrobot that can actuate for a long period under a physiological condition. The microrobot consists of three separate front and rear legs which have a shape of the microcantilever. The performance of our crab-like microrobot was measured at an average velocity of 100 mum/s, and the estimated total distance it traveled was 50 m for a one-week period. Finally, a micropump actuated by the self-beating cardiomyocytes is fabricated and the pumping performance is demonstrated.

Recently, the capsule endoscope can be widely used for the diagnosis of digestive organs. It is passively moved by the peristaltic waves of gastro-intestinal tract and thus has some limitations for doctor to get the image of the organ and to diagnose more thoroughly. As a solution of these problems, therefore, a locomotive mechanism of capsule endoscopes has being developed. Our proposed capsule-type microrobot has synchronized multiple legs that are actuated by a linear actuator and two mobile cylinders inside of the capsule. By the novel kinematic relation between the legs and the mobile cylinders, the microrobot can easily move forward in the gastro-intestine. For the feasibility test of the proposed locomotive mechanism, a series of experiments were carried out including in-vitro and in-vivo tests. Based on the experimental results, we conclude that the proposed locomotive mechanism is not only easy to be used for micro capsule endoscopes but also effective to move inside of intestinal tract.

Diseases in the gastro-intestinal tract are on an increasing trend. In order to diagnose a patient, various signals of the digestive organ, such as temperature, pH, and pressure, can offer the helpful information. Among the above mentioned signals, we choose the pressure variation as a monitoring signal. The variation of a pressure signal of the gastro-intestinal tract can offer the information of a digestive trouble or some clues of the diseases. In this paper, a pressure monitoring system for the digestive organs of a living pig is presented. This is why a pig’s gastro-intestinal tract is very similar as human’s. This system concept is to transmit the measured biomedical signals from a transmitter in a living pig to a wireless receiver that is positioned out of body. The integrated solution includes the following parts: (1) the swallow type pressure capsule, (2) the receiving set consisting of a receiver, decoder box, and PC. The merit of the proposed system is that the monitoring system can supply the precise and repeatable pressure in the gastro-intestinal tract. In addition, the design of low power consumption enables it to keep sending reliable signals while the pressure capsule is working in the digestive organ. The subject of the study for the pressure monitoring system is in-vivo experiments for a living pig. We achieved the pressure tracings in digestive organs and verified the validity of system after several in-vivo tests using the pressure monitoring system.

Recently, diseases in gastro-intestinal tract have drastically increased. As a result, endoscopic technologies are being developed to diagnose and treat these diseases. Bio-material property is essential information to develop endoscopic devices especially capsule type endoscope. Because the capsule endoscope is moved by the peristaltic motion, it has some limitations to get the image of the digestive organ. Therefore, locomotive mechanism for capsule is necessary. In order to develop the locomotive mechanism, the information of bio material property is required. Especially, the friction force between capsule endoscope and the tissues of the gastro-intestinal tract is very important information. In this paper, we propose the bio-material property measuring system which can supply the information for the design of the locomotive mechanism. By using the proposed measuring system, we evaluate the effects of design parameters such as velocity, diameter size and shape of capsule endoscope that influence the friction force to the capsule endoscope to get the dominant parameters. As a result, we can offer the useful information to design the locomotive mechanism of the capsule endoscope.

A wireless capsule endoscope, M2A, has been developed to replace the conventional endoscope. However, the commercialized capsule endoscope moves passively by peristaltic waves and gravity, which has some limitations for doctors to diagnose more thoroughly and actively. In order to solve this problem, a locomotive mechanism is proposed for a wireless capsule endoscope. Based on the tests of various actuators, a piezoactuator is selected as a microactuator for the capsule endoscope. Piezoactuators are known to have limited displacement with high voltage supply. In order to overcome the limitation of common piezoactuator, the impact based piezoactuator is developed to realize long stroke up to 11 mm. Moreover, clampers mimicked the claw of insects are employed. A prototype of the earthworm-like locomotive mechanism integrated with an impact based piezoactuator and engraved clampers is developed. It has 15 mm in diameter and 30 mm under retraction stage and 41 mm under elongation stage in total length. Hollow space is allocated to comprise essential endoscope components such as a camera, communication module, battery, and biosensors. For the feasibility test of proposed locomotive mechanism, a series of experiments was carried out including in-vitro tests. Based on results of the experiments, we conclude that the proposed locomotive mechanism is effective to be used for microcapsule endoscopes.

Recently, the microrobot powered by biological muscle actuators was proposed. The cell based actuator utilizes glucose as a power source and thus can apply to the application of a human body or blood vessels. For the structural design of the cell based micro-robot, the contractile force of the muscle powered by cardiac myocytes should be measured. In addition, the contractile force measurement can be used in the static or dynamic simulations of the micro-robot. In this paper, the contractile force measurement system, which is composed of a micro-manipulator, a force transducer, a signal processor and an inverted microscope is proposed. By using the measuring system, the contractile force for both control and micro-patterned cardiac myocytes are measured. From the experimental results, we estimated that the contractile force of cardiac myocytes is about 20-40 /spl mu/N when it is compared between the control cell and the cell on micro-pattern.

Recently, diseases in gastro-intestinal tract have drastically increased. As a result, endoscopic technologies are being developed to diagnose and treat these diseases. Biomaterial property is essential information to develop endoscopic devices especially capsule type endoscope. For the past decades, experiments to obtain material property of gastro-intestinal tract are performed on in-vitro state. Therefore, material properties of digestive organs are not in-vivo test result but in-vitro result. In this research, we design, develop, and fabricate a bio-material property measurement (BMPM) system. The measuring system consists of a probing device, tendon device and suction part. The probe measures the force transmitted from the biomaterial as the sensing module protrudes based on the tendon controls, while the suction device seizes the organ. By using the system, we can measure the local deformation force and the piercing force. The measured deformation and piercing force data can be used for the locomotive and clamping mechanism design of the capsule type endoscope. In order to evaluate the validity of the BMPM, we perform the operation in an esophagus, stomach and colon of a pig. In conclusion, we could measure each organ's material properties under in-vitro state without dissection of digestive organs. Some in-vivo test results are expected to design endoscopic devices using the proposed BMPM system.