We already synthesized a highly efficient water-soluble two-photon photoinitiator (P2CK) and methacrylic anhydride modified gelatin (GelMA), which were used together as a new photoresist for direct 3D printing of soft hydrogel microrobots. Template-assisted fabrication together with infiltration of biodegradable polymers was also developed for fabrication of soft microrobots with materials that are capable of being 3D-printed. Biocompatible iron oxide nanoparticles and iron were successfully integrated with aforementioned techniques to provide motile components for the microrobots under magnetic actuation. The fabricated microrobots showed excellent biocompatibility, and can be degraded by the enzymes secreted by cells. Some of these devices were demonstrated to be able to deliver drugs efficiently or act as a shape memory stent for fetal urinary tract obstruction. We also developed actuation strategies that enable selective control of individual microrobots within a swarm, and strategies that transport microrobots along or against the flow.
We developed magnetic tools and micro-catheters for several medical applications. A magnetic needle to steer electrodes to perform Deep Brain Stimulation (DBS) was developed and tested on agar phantoms as well as pig cadaveric brains. A dedicated path-planning method to safely reach regions in the brain along curved trajectories was implemented and evaluated in simulation, showing increased safety and versatility over conventional approaches. Micro-catheters for vitreoretinal surgery including sub-retinal injections, epiretinal membrane peeling, or endolaser photocoagulation were also developed. Several strategies were considered, including the use of variable stiffness tools to increase the dexterity and reliability of our magnetic catheters. We tested these prototype concepts in phantom eyes as well as excised pig cadaveric eyes, also making use of medical imaging modalities such as OCT technology to evaluate the performance of our designs. We also proposed new mechanical designs and actuation paradigms for robotically-guided endoscopic procedures such as gastroscopy and enteroscopy. An innovative design for the distal magnetic section of these device was also introduced to significantly improve the dexterity of these tools over the existing state-of-the-art.
We implemented specific models for these magnetic continuum robots, including the use of Cosserat rod models and FEM-based real-time simulations. These models and simulation frameworks are suitable both for the design of surgical simulators, and for an integration within control algorithms to steer magnetic tools in real-time within a patient body using our electromagnetic navigation systems (eMNS). We also contributed to new strategies to localize precisely and in real-time tethered and untethered magnetic devices within the human body. These strategies include the use of static and dynamic magnetic fields to be measured by magnetic sensors embedded in the devices to be localized. We demonstrated this approach at various scales and with a broad variety of eMNS available at our experimental facilities.
A new design of eMNS was also proposed during this project. It exhibits high performance electromagnets and has a reduced size and weight, with the idea of integrating the system within existing operating rooms. Our objective was to bring magnetic navigation technology closer to the clinical application and foster synergy between our researchers and the medical staff. The system has been demonstrated in different pre-clinical environments, and to perform a large variety of procedures in-vitro and ex-vivo and using various medical imaging modality including fluoroscopy, and endoscopic imaging.
The outcome of the project has been extensively disseminated on the international stage with more than 40 peer-reviewed publications in international journals. It also led to several patent applications in the field of medical robotics, and magnetically guided devices.
