Visually guided grasping to study teleprogrammation within the BAROCO testbed

This paper describes vision functionalities required in future orbital laboratories; in such systems, robots will be needed in order to execute the on-board scientific experiments or servicing and maintenance tasks under the remote control of ground operators. For this sake, ESA has proposed a robotic configuration called EMATS; a testbed has been developed by ESTEC in order to evaluate the potentialities of EMATS-like robot to execute scientific tasks in automatic mode. For the same context, CNES develops the BAROCO testbed to investigate remote control and teleprogrammation, in which high level primitives like 'Pick Object A' are provided as basic primitives. In nominal situations, the system has an a priori knowledge about the position of all objects. These positions are not very accurate, but this knowledge is sufficient in order to predict the position of the object which must be grasped, with respect to the manipulator frame. Vision is required in order to insure a correct grasping and to guarantee a good accuracy for the following operations. We describe our results about a visually guided grasping of static objects. It seems to be a very classical problem, and a lot of results are available. But, in many cases, it lacks a realistic evaluation of the accuracy, because such an evaluation requires tedious experiments. We propose several results about calibration of the experimental testbed, recognition algorithms required to locate a 3D polyhedral object, and the grasping itself

New polymer coating to visualize surgical mesh by MRI

International audienc

New magnetic-resonance-imaging-visible poly(epsilon-caprolactone)-based polyester for biomedical applications

A great deal of effort has been made since the 1990s to enlarge the field of magnetic resonance imaging. Better tissue contrast, more biocompatible contrast agents and the absence of any radiation for the patient are some of the many advantages of using magnetic resonance imaging (MRI) rather than X-ray technology. But implantable medical devices cannot be visualized by conventional MRI and a tool therefore needs to be developed to rectify this. The synthesis of a new MRI-visible degradable polymer is described by grafting an MR contrast agent (DTPA-Gd) to a non-water-soluble, biocompatible and degradable poly(epsilon-caprolactone) (PCL). The substitution degree, calculated by H-1 nuclear magnetic resonance and inductively coupled plasma-mass spectrometry, is close to 0.5% and proves to be sufficient to provide a strong and clear T1 contrast enhancement. This new MRI-visible polymer was coated onto a commercial mesh for tissue reinforcement using an airbrush system and enabled in vitro MR visualization of the mesh for at least 1 year. A stability study of the DTPA-Gd-PCL chelate in phosphate-buffered saline showed that a very low amount of gadolinium was released into the medium over 52 weeks, guaranteeing the safety of the device. This study shows that this new MRI-visible polymer has great potential for the MR visualization of implantable medical devices and therefore the post-operative management of patients. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

Permanent Polymer Coating for in vivo MRI Visualization of Tissue Reinforcement Prostheses

The clinical advantage of MRI visualization of prostheses in soft tissue prolapses is very appealing as over 1?000?000 MRI-transparent synthetic meshes are implanted annually, and postoperative complications such as mesh shrinkage and migration are frequent. Here, the synthesis of a new material composed of a DTPA-Gd complex grafted onto a backbone of PMA via a covalent bond is described (DTPA-Gd-PMA). This new polymer is sprayed onto meshes and gives an MR signal for a long period without any significant release of Gd. In vitro cytocompatibility tests on fibroblasts show limited cytotoxicity. Microscopic investigations indicate that vital cells rapidly colonize the material. Finally, coated meshes implanted in rats are easily recognizable using an MR imaging system

Copolymère hydrophobe visible en IRM

The invention relates to a hydrophobic thermoplastic copolymer which is in particular of use for manufacturing and/or coating medical devices, in particular implantable medical devices, characterized in that it is obtained by copolymerization, and in that it comprises at least one first monomer unit and at least one second monomer unit onto which is grafted a paramagnetic-ion-chelating ligand which can complex with such a paramagnetic ion or a paramagnetic-ion-chelating ligand which is complexed with such a paramagnetic ion, wherein the second monomer unit is grafted in sufficient amount for the copolymer to be visible in magnetic resonance imaging when it is complexed with said paramagnetic ion. The invention also relates to a method for obtaining said hydrophobic thermoplastic copolymer

MR Chemical engineering of polymer for medical devices visualization.

International audienc

MRI-visible polymer based on poly(methyl methacrylate) for imaging applications

Macromolecular contrast agents are very attractive to afford efficient magnetic resonance imaging (MRI) visualization of implantable medical devices. In this work, we report on the grafting of a Gd-based DTPA contrast agent onto a poly(methyl methacrylate) derivative backbone by combining free radical polymerization and copper-catalyzed azide-alkyne cycloaddition (CuAAC). Using free radical polymerization, poly(methyl methacrylate-co-propargyl methacrylate) copolymers were prepared with a control of the ratio in propargyl methacrylate monomer units. The synthesis of a new azido monofunctionalized DTPA ligand was also reported and characterized by 1H NMR and mass spectroscopy. After complexation with gadolinium, this ligand has been grafted on the polymer backbone by click chemistry reaction. The obtained macromolecular contrast agent was then coated on a polypropylene mesh using the airbrushing technique and the mesh was assessed for MRI visualization at 7 teslas. The polymeric contrast agent was also tested for cytocompatibility and stability to assess its suitability for biomedical applications

Conception de prothèse visible en IRM pour la prise en charge chirurgicale des prolapsus génitaux et des hernies abdominales

National audienc

Conception of an anti-infectious and MRI visible mesh used for pelvic organs prolapse and abdominal hernias surgery

International audienceLa pose chirurgicale de prothèses afin de pallier les descentes d'organes de la zone pelvienne ou pariétale est une opération de plus en plus fréquente et requière l'implantation de plus de 1 200 000 dispositifs médicaux annuellement. Or, les cas de complications et de réinterventions chirurgicales restent très élevés, principalement dus aux infections associées à une réponse inflammatoire importante, ainsi qu'aux érosions, expositions et migrations des prothèses. Ces travaux présentent différentes stratégies permettant d'apporter des propriétés de résistance à l'infection et de suivi postopératoire à l'aide d'une visibilité en IRM à des treillis. Pour cela, un enrobage de polymères dégradables (polyesters) piégeant des antibiotiques est créé à l'aide d'un aérographe autour des filaments des treillis tout en conservant leurs aspects morphologiques et leurs propriétés mécaniques. Cet enrobage temporaire permet une libération prolongée de principes actifs inhibant l'adhésion bactérienne, la formation de biofilm et la prolifération bactérienne périprothétique pendant plus de trois jours in vitro. Parallèlement, des polymères contenant des agents de contraste greffés sur leur squelette carboné ont été utilisés comme agent d'enrobage, afin d'apporter des propriétés de visibilité en IRM aux treillis. In vitro, ces treillis enrobés induisent un signal significatif en IRM expérimentale (7 Tesla) et présentent une très bonne stabilité de l'agent de contraste, quelle que soit la technique de stérilisation employée. Surgical operations for soft tissue reinforcement (i.e. pelvic organs prolapse or abdominal hernias) are common procedures and require annually at least 1,200,000 of prostheses. Unfortunately, postoperatory complications and reinterventions are still important, mainly due to infection, inflammation, erosion, exposition or meshes migration. We present here several strategies to bring to meshes anti-infective resistance and clinical follow-up capability through an MRI visible material. A coating of the mesh by degradable polymers (polyesters) trapping antibiotics was created using an airbrushing technique, without modifying dramatically the morphology and the mechanical properties of the meshes. This temporary drug reservoir-coating allows a sustained release of the drugs and hamper in vitro bacterial contamination and biofilm formation on the meshes, associated to a large periprosthetic microorganism growth inhibition for a minimum of three days. Simultaneously, magnetic resonance contras