Parametric design, fabrication and validation of one-way polymeric valves for artificial sphincters

Abstract The design of artificial sphincters requires an accurate dimensioning of dedicated valves, normally made of polymeric materials. This effort is also interesting for developing fluid and pressure regulating solutions related to other biomedical and non-biomedical fields. In this article we focused on the parametric design of polymeric valves, by taking inspiration from commercially exploited solutions used in the food industry and performing appropriate scaling in order to make them suitable for artificial organs and components. In addition, different materials with diverse mechanical properties were considered, focusing on a low-cost fabrication approach. Finite element model analyses were conducted to simulate the behavior of different valve profiles and to predict the valve opening pressure. Simulation results were validated by comparing them with experimental results, obtained by fabricating and testing different valve types. This polymeric valve parametric analysis may be exploited for the design of artificial sphincters, having the potential to tackle urinary incontinence, a disease that affects about 350 million people worldwide

Medical Microrobots

: Scientists around the world have long aimed to produce miniature robots that can be controlled inside the human body to aid doctors in identifying and treating diseases. Such microrobots hold the potential to access hard-to-reach areas of the body through the natural lumina. Wireless access has the potential to overcome drawbacks of systemic therapy, as well as to enable completely new minimally invasive procedures. The aim of this review is fourfold: first, to provide a collection of valuable anatomical and physiological information on the target working environments together with engineering tools for the design of medical microrobots; second, to provide a comprehensive updated survey of the technological state of the art in relevant classes of medical microrobots; third, to analyze currently available tracking and closed-loop control strategies compatible with the in-body environment; and fourth, to explore the challenges still in place, to steer and inspire future research

A Power-efficient Propulsion Method for Magnetic Microrobots

Current magnetic systems for microrobotic navigation consist of assemblies of electromagnets, which allow for the wireless accurate steering and propulsion of sub-millimetric bodies. However, large numbers of windings and/or high currents are needed in order to generate suitable magnetic fields and gradients. This means that magnetic navigation systems are typically cumbersome and require a lot of power, thus limiting their application fields. In this paper, we propose a novel propulsion method that is able to dramatically reduce the power demand of such systems. This propulsion method was conceived for navigation systems that achieve propulsion by pulling microrobots with magnetic gradients. We compare this power-efficient propulsion method with the traditional pulling propulsion, in the case of a microrobot swimming in a micro-structured confined liquid environment. Results show that both methods are equivalent in terms of accuracy and the velocity of the motion of the microrobots, while the new approach requires only one ninth of the power needed to generate the magnetic gradients. Substantial equivalence is demonstrated also in terms of the manoeuvrability of user-controlled microrobots along a complex path

An Integrated Triangulation Laser Scanner for Obstacle Detection of Miniature Mobile Robots in Indoor Environment

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Magnetic Field-Based Technologies for Lab-on-a-Chip Applications

In the last decades, LOC technologies have represented a real breakthrough in the field of in vitro biochemical and biological analyses. However, the integration of really complex functions in a limited space results extremely challenging and proper working principles should be identified. In this sense, magnetic fields revealed to be extremely promising. Thanks to the exploitation of external magnetic sources and to the integration of magnetic materials, mainly high aspect ratio micro-/nanoparticles, non-contact manipulation of biological and chemical samples can be enabled. In this chapter, magnetic field-based technologies, their basic theory, and main applications in LOC scenario will be described by foreseeing also a deeper interaction/integration with the typical technologies of microrobotics. Attention will be focused on magnetic separation and manipulation, by taking examples coming from traditional LOC devices and from microrobotics

Design, Realization, and Assessment of a High-Fidelity Physical Simulator for the Investigation of Childbirth-Induced Pelvic Floor Damage

Vaginal delivery is one of the main causes of pelvic floor damage, which can lead to short- and long-term clinical consequences called pelvic floor dysfunctions. The number of women affected by this pathology is continuously rising, representing both a medical issue and an important financial burden. Prevention represents the best strategy of care, but it requires a deep understanding of the injury mechanisms, which is currently lacking. Simulation can help to identify the main factors affecting a clinical event, reducing the need for in vivo investigations. However, current simulators poorly mimic the pelvic structures and do not provide any feedback. These limitations led to the development of an innovative high-fidelity physical simulator to study the mechanisms behind pelvic floor damage caused by vaginal delivery. Anatomically correct gynecological structures were realized using soft materials able to resemble human tissue behavior. Ad hoc stretch sensors were realized with conductive fabric and integrated into the simulator to evaluate tissue elongation caused by the passage of the fetal head. Evaluation of the simulator was carried out both in laboratory conditions and by involving expert clinicians. Gynecologists determined that the simulator is a valid teaching and training tool that is able to provide feedback on instantaneous pelvic floor elongation, thus potentially preventing induced tissue damage

Design, Fabrication, and Testing of a Capsule With Hybrid Locomotion for Gastrointestinal Tract Exploration

Abstract—This paper describes a novel solution for the active lo-comotion of a miniaturized endoscopic capsule in the gastrointesti-nal (GI) tract. The authors present the design, development, and testing of a wireless endocapsule with hybrid locomotion, where hybrid locomotion is defined as the combination between internal actuation mechanisms and external magnetic dragging. The cap-sule incorporates an internal actuating legged mechanism, which modifies the capsule profile, and small permanent magnets, which interact with an external magnetic field, thus imparting a dragging motion to the device. The legged mechanism is actuated whenever the capsule gets lodged in collapsed areas of the GI tract. This allows modification of the capsule profile and enables magnetic dragging to become feasible and effective once again. A key com-ponent of the endoscopic pill is the internal mechanism, endowed with a miniaturized brushless motor and featuring compact design, and adequate mechanical performance. The internal mechanism is able to generate a substantial force, which allows the legs to open against the intestinal tissue that has collapsed around the capsule body. An accurate simulation of the performance of the minia-turized motor under magnetic fields was carried out in order to define the best configuration of the internal permanent magnets (which are located very close to the motor) and the best tradeoff operating distance for the external magnet, which is responsible for magnetically dragging the capsule. Finally, a hybrid capsule was developed generating 3.8 N at the tip of the legged mechanism and a magnetic link force up to 135 mN. The hybrid capsule and its wireless control were extensively tested in vitro, ex vivo, and in vivo, thus confirming fulfilment of the design specifications and demon-strating a good ability to manage collapsed areas of the intestinal tract. Index Terms—Capsule endoscopy, endoscopic capsule, magnetic locomotion, robotic surgery. I