Background: An endomyocardial biopsy (EMB) is an invasive procedure where biopsy samples are taken from within the heart for diagnosis of different myocardiopathies and or heart transplant rejection monitoring. During EMB procedures, a minimum of five tissue samples are required to be taken from the heart wall for investigation. Current bioptomes are not able to retrieve more than one sample at a time and therefore need to be re-inserted at least four times. This can lead to complications such as air embolisms. The goal of this design study was to develop a novel cardiac bioptome for endomyocardial biopsies that can take and store multiple biopsy samples during a single insertion. Design: The bioptome developed in this study had two major functionalities, resection of myocardial tissue and storage of multiple tissues. Each functionality could be divided into multiple sub-functionalities. From these functionalities the design requirements followed. Afterwards, the alternatives for each subfunctionality were explored. For the tissue resection, different possibilities for the method of resection, position of the resection tool, direction of resection forces, and motion of resection, were explored. For tissue storage, different possibilities for the storage system, tissue transportation, and sample loss prevention were explored. Following this exploration, multiple design concepts were devised. Two of these concepts, the ’corer’ concept and ’ovipositor’ concept were developed further. These two concept were compared and the ’corer’ concept was chosen as the most viable option. Prototypes of this concept were developed and tested for the functioning of its working principle for tissue resection and storage and for the functioning of the actuation mechanism. Results: The experiments showed that the end-effector of the bioptome works as expected and that thus the working principle of the ’corer’ concept for resection and storage of biopsy samples functions as intended. The experiments also validated the functioning of the actuation mechanism within the handle. The experiments however also showed that the flexible shaft was unable to correctly transfer the motion from the actuation mechanism in the handle to the end-effector. Discussion & conclusion: More suitable materials are required for future prototypes to improve motion transfer. Furthermore, a steerability functionality should be added to the design to make the bioptome fully functional for EMB procedures. The final design should be tested in an environment more closely resembling the clinical scenario. If these tests are successful, it can be concluded that the bioptome can indeed improve endomyocardial biopsy procedures.

Endoscopic instruments are integral components of minimally invasive procedures, widely used for diagnoses and treatment of diseases. When navigating the endoscope, it should experience a minimum of friction, while an increase in friction is beneficial for performing the medical procedure. Friction can be reduced by squeeze film levitation, where air is trapped and pressurized between two surfaces by vibrating one of these surfaces. The squeeze film levitates the two surfaces away from each other, hereby reducing friction. Squeeze film levitation between a rigid curved surface and a soft surface is still poorly understood. Also, a proof of concept of a friction modulation mechanism for endoscopes is not yet available in the research literature. Therefore, this paper describes the design and experimental validation of an ultrasonic vibrating ring that can actively modulate friction by generating a squeeze film. On a steel surface, the friction is reduced considerably. However, on the two soft surfaces described in this paper, the reduction of friction is absent.

Colonoscopy is a widely used endoscopic procedure to diagnose colorectal cancer (CRC) which is considered the fourth most common cancer in the US and the second most common cancer in Europe. Colonoscope, used in colonoscopy, consists of a thin flexible hollow tube that is inserted into the rectum of a person and propagated through the entire colon. The disadvantage of the current procedure is that the colonoscope has to be pushed from outside to move through the colon resulting in recurrent looping of the colonoscope due to buckling. Recurrent looping inflicts the risk of tissue damage and is responsible for approximately 90% of the pain experienced by patients during colonoscopy. Research was carried out to create self-propelling colonoscopes which would eliminate the force required to push the device from outside. Inspirations were taken from the locomotion of earthworms to develop self-propelling colonoscopes however, the device’s propulsion was hindered due to friction and low axial stiffness of the colon wall. In this study, a proof of concept for a self-propelled colonoscopic device inspired by the ovipositor of wasps was conducted which resulted in the development of a prototype. The prototype was tested in a colon-simulated environment and it was able to successfully propel through the prepared colon phantom after an initial manual run through the colon phantom. The requirement of an initial manual run was speculated to be due to the capillary adhesion and uneven oil spread in the colon phantom. The device had an average velocity of around 5.68 mm /s inside the colon phantom with an average efficiency of 72.5%. In the future, the prototype has to be tested in an actual colon to assess its functionality and evaluate the propulsion efficiency of the prototype in a real colon.