BACKGROUND AND STUDY AIMS:The use of magnetic fields to control operative devices has been recently described in endoluminal and transluminal surgical applications. The exponential decrease of magnetic field strength with distance has major implications for precision of the remote control. We aimed to assess the feasibility and functionality of a novel wireless miniaturized mechanism, based on magnetic forces, for precise orientation of the camera. MATERIALS AND METHODS:A remotely controllable endoscopic capsule was developed as proof of concept. Two intracapsular moveable permanent magnets allow fine positioning, and an externally applied magnetic field permits gross movement and stabilization. Performance was assessed in ex vivo and in vivo bench tests, using porcine upper and lower gastrointestinal tracts. RESULTS:Fine control of capsule navigation and rotation was achieved in all tests with an external magnet held steadily about 15 cm from the capsule. The camera could be rotated in steps of 1.8 degrees . This was confirmed by ex vivo tests; the mechanism could adjust the capsule view at 40 different locations in a gastrointestinal tract phantom model. Full 360 degrees viewing was possible in the gastric cavity, while the maximal steering in the colon was 45 degrees in total. In vivo, a similar performance was verified, where the mechanism was successfully operated every 5 cm for 40 cm in the colon, visually sweeping from side to side of the lumen; 360 degrees views were obtained in the gastric fundus and body, while antrally the luminal walls prevented full rotation. CONCLUSIONS:We report the feasibility and effectiveness of the combined use of external static magnetic fields and internal actuation to move small permanent intracapsular magnets to achieve wirelessly controllable and precise camera steering. The concept is applicable to capsule endoscopy as to other instrumentation for laparoscopic, endoluminal, or transluminal procedures.

This work focuses on the realization of three different micro-actuators that will be integrated in a lab-on-chip for bioaffinity assays. The aim is to create a microfluidic network to control the sample and reagent delivery as well as the washing cycles for a complete analysis. The three micropumps have different working principles (electromagnetic, electrolytic and peristaltic actuation methods), but they share the same fabrication process. The reason for adopting three different actuation modes is mainly related to the different functionalities that have to be managed at microfluidic level. In particular the electrolytic one-shot micropump will be used for sample and reagents delivery, while the peristaltic and the electromagnetic micropumps are both good candidates for the washing cycles.

This work presents the design, fabrication and characterization of a polymer based stretchable electrode for cell monitoring. The final goal is the development of innovative bio-hybrid skin-like tactile sensors with mammalian cells as core biological elements; to achieve such aim the enabling technological approach is pursued in this investigation. Electrodes are needed to detect cells response, thus the first step of the bio-hybrid system fabrication is the development of a platform able to record such response and transmit it to the external world. The stretchable electrode is composed by a conductive layer (few Ǻ of Ti plus 90nm of Au) on a polymeric substrate (1mm thick PDMS membrane). Cellular adhesion was verified and cellular response to an induced electrode strain of 1% was detected through fluorescence microscopy. Fluorescence intensities were 104.82±9.64a.u. and 129.66±13.06a.u. prior and during electrode strain, respectively. Electromechanical characterization of the stretchable electrode revealed excellent stability and reliability within the 1% strain, which is the operative range identified for the future tactile sensor application. Results showed that the electrode was conductive up to 14% of strain. Furthermore, frequency impedance measurements demonstrated the electrode capability of detecting presence of cells.

This paper illustrates the design, development and testing of a miniature mechanism to be integrated in endoscopic capsules for precise steering capabilities (Magnetic Internal Mechanism, MIM). The mechanism consists of an electromagnetic motor connected to a couple of small permanent magnets and immersed in a static magnetic field produced by an external permanent magnet or a by an electromagnetic coil. The overall steering capsule, integrating the magnetic steering mechanism and the vision system is 15.6 mm in diameter, 48 mm in length, 14.4 g in weight and can be oriented with an accuracy of 0.01 degrees . As regards system scalability, the capsule size could be reduced down to 11 mm in diameter by optimizing some mechanical components. On the other hand, the magnets size cannot be reduced because the magnetic link between internal and external magnets at typical operation distances (about 15 mm) would be weak.

A number of unique challenges arise in fabricating and assembling complex mechanisms at the meso-scale (hundreds of microns to centimetres). In general, for a complex multi-part mechanism at this length scale, no single machining technique can produce all the necessary parts—or often even a single individual part. Towards developing a comprehensive set of 'best practices' for combining multiple precision micromachining operations at the meso-scale, we present a case study on fabricating and assembling an endoscopic capsule robot. Existing passive imaging capsules have proven exceptionally useful in the diagnosis of the gastrointestinal tract, and robotic capsules promise to enhance their diagnostic capabilities and enable non-invasive treatment delivery. In this case study, we describe the fabrication of a robotic capsule (2.6 cm 3 in volume) containing a complex mechanism consisting of 72 components, each of which requires a variety of meso-or even micro-scale features. We describe the manufacturing processes used to produce these components and features (combinations of high precision, multiply refixtured computer numerical control processes, sink and wire electro discharge machining , laser cutting, etc). These results contribute to the emerging framework of best practices in meso-scale design and manufacture, illustrating ways to effectively combine several processes to produce a complex meso-scale device.