Multi-shank flexible implantable neural interface for long-term olfactory neuron recording toward odor perception

Abstract

Odor perception systems based on the chip-organism hybrid strategy display significant advantages in detection specificity and sensitivity. However, due to poor biocompatibility and the extreme mismatch of Young’s modulus, the relative displacement between cells and the electrodes leads to recording failures, thereby shortening the lifespan of the chip-organism hybrid models. Here, we proposed a multi-shank flexible implantable neural interface suitable for large-scale recording of olfactory neurons to extend the working lifetime of the model. First, SU-8 thin film-based neural interfaces were fabricated by micro-nano processing to reduce the rigidity of the neural recording chips. Next, the recording performance was improved by the in situ deposition of platinum nanoparticles. The mechanical properties of the neural interfaces were significantly enhanced to implantation when they were wrapped with a water-soluble material. Afterward, we combined the neural interfaces with rat olfaction to build a polymer-organism hybrid electronic nose for odor perception. We found that the multi-shank flexible implantable neural interface could record high-quality signals of the rat olfactory bulb for up to 11 months. Finally, by using pattern recognition algorithms, the polymer-organism hybrid electronic nose could achieve an odor perception and recognition accuracy of 97.5 % when the rats were awake. This polymer-organism hybrid strategy has great potential for studying long-term olfactory functions and enhancing the odor perception capabilities of chip-organism hybrid devices.