A Single Electrode Organic Neuromorphic Device for Dopamine Sensing in Vivo

Organic Electronic platforms for biosensing are being demonstrated at a fast pace, especially in healthcare applications where the use of organic (semi-)conductive materials leads to devices that efficiently interface living matter. Nevertheless, interesting properties of organic (semi-)conductors are usually neglected in the development of (bio-)sensors. Among these, the non-linear response when operated under dynamic biasing conditions (i.e., with pulsed driving voltages), thus mimicking synaptic plasticity phenomena, offers promising and largely unexplored possibilities for bio-sensing. The artificial synaptic response's figures of merit reflect the composition of the surrounding environment and, ultimately, the ion concentration and dynamics at the organic (semi-)conductor/electrolyte interface. Therefore, new sensing strategies that rely on the effect of target analytes on the short-term plasticity response of Organic Neuromorphic Devices are being demonstrated. This work presents the development of a label-free Single Electrode Neuromorphic Device (SEND) specifically designed for in vivo real-time mapping of dopamine concentration. The device response is investigated as a function of the driving frequency, resulting in the determination of the optimal operational configuration for minimally invasive neuromorphic devices. It exhibits stable multi-parametric response in complex fluids, in brain's mechanical models and in vivo, enabling monitoring of local variations of dopamine concentration in the rat brain.