Bioresorbable Endovascular Neural Interface for Minimally Invasive Neural Stimulation and Recording

Recording and stimulation of brain circuits have been widely used to treat neurological disorders, such as epilepsy1 and Parkinson’s disease2. Current available techniques in this field commonly require invasive surgery potentially entailing both transient and permanent complications3. A promising strategy designed to overcome4these risks involves the exploitation of the cerebrovascular system as access route of the neural tissue . Electrodes mounted on wires and catheters have been used as recording systems since early 1970s and the results have been proved to be comparable to those achieved via established methods6. On the other hand, deep brain stimulation (DBS) performed with an endovascular approach has only been studied at a computational level, by Teplitzky et al. showing the possible targets for an endovascular stimulation. In their study, it is also suggested the replacement of wire electrodes with ring ones, as these provide a better adaptation to the vessel walls, reducing the distance to the target and improving the neural activation7. Thus, the exploitation of stenting technology, exceptionally designed to adhere to blood vessel walls, represents an optimal scaffold for the recording/stimulating system. Oxley et al. mounted electrodes on commercially available, self-expandable Nitinol stents and pursued preliminary studies on sheep. Their results were comparable to those obtained with epidural electrodes arrays. However, device fractures owed to repetitive neck movements and chewing muscle artifacts were reported. Moreover, permanent metallic implants usually lead to delayed endothelialization, chronic local inflammation and thrombogencity8. A promising solution to minimize these drawbacks is the use of soft, biocompatible and biodegradable polymers, able to adapt to complex geometries and absorb impacts. Therefore, we designed a novel neurovascular interface where 6 electrodes and their interconnects made of (3‐glycidyloxypropyl)trimethoxysilane-doped poly(3,4-ethylenedioxythiophene) : poly(styrenesulfonate) (GOPS-doped PEDOT:PSS) are embedded in poly-ε-caprolaptone (PCL). The given shape (Fig. 1A) allows easy folding of the device inside tubes (Fig. 1C) for smooth in situ deployment. The 6 electrodes are placed at the struts junctions that can hold diameters up to 700μm (Fig. 1B). In summary, this innovative device entirely made of biodegradable and biocompatible materials will offer an alternative solution to the invasive techniques currently used for neural recording and brain stimulation. Its development potentially will have a huge impact in the treatment of neuropathological conditions.