Final Report Summary - MULTISENS (Multi-sensing polymer transistors for in vivo recording) MultiSENS was aimed at developing a new generation of multi-sensing implantable probes, employing the communication between organic electrochemical transistors (OECTs) and neurons. Developing such multi-sensing probes requires the combination of expertise in electronic materials and micro-fabrication, electronic instrumentation, and organic electronics. The project was focused on the design and fabrication of the actual probes, with a following in vitro and/or in vivo monitoring of neuronal activity (carried out by collaborators). Through collaborations with the microelectronics industry and partners in life sciences research, the applications of OECTs in biomedical implants and sensors was explored. The fellow trained on the fabrication and physics of organic electronic devices and on cell culture, as a model for in vivo recording. He visited the laboratory of Prof. Gordon Wallace at the University of Wollongong, Australia, where he learned the techniques permitting chemical functionalization of conducting polymers with bio-active molecules, such as enzymes or extracellular matrix poly-anions. He also visited several times the laboratory of Dr. Christophe Bernards at the University of Aix-Marseille where he trained on in vivo recording of electrophysiological activities from rat brains and analysis techniques. The fellow developed a generic lithographic process that allows the fabrication of microelectrodes arrays (MEAs) and high density OECTs arrays meant to interface with living cells and brain tissue. He tested these devices using tissue slices and demonstrated the ability to record neuronal activity. Moreover, biomolecules such as enzymes or adhesion peptides were patterned on these devices to promote cell growth. The project led to four publications in peer-reviewed journals, three of which have an impact factor > 10. Two more are submitted, while a final one is being written. Between the fellow and the supervisor, >20 talks were given at international conferences or universities, including a plenary talk at the 2012 E-MRS meeting.The fellow participated in outreach to the general public, during the annual festival of science (fête de la science), the open day of the Gardanne campus of the Ecole des Mines. These events hosted over a thousand visitors and included many experimental demonstrations for children of primary schools and their parents. An exhibit on bioelectronics was displayed that included commercial and our own implants, as well as a presentation of some of our findings from MultiSENS project.An electrophysiology instrumentation company called MICROVITAE (an SME) is interested in this technology, though the results are still too early-stage for commercialization. Our laboratory is a recipient of a PhD student grant from MICROVITAE to further develop conducting polymer devices for neural interfacing.