Implantable Bioelectronics with Shape Actuation for Minimally Invasive Electrocorticography

The development of innovative neural interface devices would allow for novel approaches to diagnose, monitor, and treat neurological conditions and impaired neural-mediated motor function. Electrocorticography (ECoG) is an implanted neural interface technique that has been developed to record brain activity using large-area electronic arrays placed on the cortical surface and is used as a diagnostic tool in Epilepsy and Parkinson’s monitoring, and brain-computer interfaces for prosthesis control. There has been extensive investigation into flexible ECoG devices, with a variety of substrate materials and electrode designs, however, the implantation of these devices is very invasive due to the size of craniotomy required.<br/>This project aims to design shape-morphing ECoG neural implants that can be implanted with minimally invasive surgical techniques, whilst still retaining the large area mapping and spatial resolution of existing ECoG technologies. We have developed a microfluidics-based soft-robotic ECoG design that allows us to deploy a folded thin-film ECoG with a small burr-hole craniotomy onto the cortical surface, before deploying the full large bioelectronic array onto the cortex using fluidic actuation. The application of soft-robotic technologies in shape-morphing implants is an emerging field, applying the use of soft polymeric materials to form actuators that enable the shape actuation of these devices post-implantation. This approach to shape-morphing bioelectronics using soft, compliant materials also allows the large bioelectronic arrays to match the surrounding soft environment of human tissue mechanically.<br/>The ECoG designs were tested in porcine models, with the integration of x-ray opaque PDMS markers allowing the expansion of the devices to be tracked with real-time fluoroscopy. This demonstrated that soft-robotic technologies would be a feasible approach for delivering larger ECoG designs to the cortical surface with a burr-hole craniotomy. By reducing the invasiveness of flexible ECoG sensors, this innovation allows for the reduction of both surgical risk and cost, increasing the availability of these sensors for clinical applications.