Francesca Santoro (RWTH Aachen): "Organic semiconductors for biomimetic electronics"

Francesca Santoro received her Bachelor’s and Master’s degrees in Biomedical Engineering at the ‘Federico II’ University of Naples (Italy) with specialization in biomaterials. She received a PhD in 2014 in Electrical Engineering and Information Technology in a joint partnership between the RWTH Aachen and the Forschungszentrum Juelich (Germany). In October 2014, she joined Stanford University (USA) and received a research fellowship in 2016 by the Heart Rhythm Society. She joined IIT in July 2017 as Principal Investigator of the 'Tissue Electronics' lab. In 2018 she has been awarded the MIT Technology Review Under 35 Innovator ITALIA and EUROPE. She has been awarded an ERC Starting Grant in 2020. She is among the Inspiring Fifty Italy and Europe and is also the winner of the Falling Walls Science Breakthrough of the Year in Engineering and Technology in 2021. Since January 2022, she is Professor in Neuroelectronic Interfaces at RWTH Aachen and Forschungszentrum Juelich. She has been recently selected as a PI in the Interstellar Initiative by the New York Academy of Science and is the recipient of the prestigious Early Career Award by the German National Academy of Science Leopoldina.

Abstract: The replication of neural information processing in electrical devices has been extensively studied over the years. The paradigm of parallel computing, which allows information to be simultaneously detected, processed, and stored, is required for numerous applications in many fields. In the case of brain-computer interfaces, another important requirement is the suitability of the device for communication with cells. Organic electrochemical transistors (OECTs) based on PEDOT:PSS are used for this purpose due to their ionic-to-electronic signal transduction and biocompatibility. Many works have demonstrated the reproduction of neural plasticity mechanisms, such as short-term facilitation and long-term potentiation. In each device, the physical mechanism of transduction may be different, but it is known that the electrolyte plays a key role in the functioning of these devices, as it provides the ions responsible for the chemical transmission of information. Focusing on long-term memory, this can be reproduced in the OECTs with the oxidation of the neurotransmitter, as in the case of the biohybrid synapse. It is crucial to understand the influence of the material chemistry, electrolyte composition and neurotransmitter-mediated memory effect of the device, as long-term modulation is based on a change in the ionic balance between the electrolyte and the organic polymer.
This electrolyte/neurotransmitter-dependency plasticity will be discussed also to consider the use of neuromorphic OECTs to be interfaced with living neurons to establish biohybrid synapses and neuronal networks.
Furthermore, I will discuss how conjugated polymers can be engineered with azopolymers (opto-sensitive polymers which switch from cis to trans conformation upon certain light exposure) to feature diverse optoelectronic short- and long-term plasticity, enabling the use of such platforms as neurohybrid devices as building blocks of retina-inspired devices as well creating functional biointerfaces with living neurons. In fact, conductive polymers and light-sensitive surface coating can also enable electromechanical coupling with neuronal cells, enhancing the cell-chip coupling at different scales. These biomimetic materials will enable a new class of bioelectronic device used for neuronal interfaces towards their application in implantable probes.