Periodic Reporting for period 2 - MITICS (Mixed Ionic and electronic Transport In Conjugated polymers for bioelectronicS)
Período documentado: 2022-02-01 hasta 2023-07-31
However, the potential of BCIs is strongly hampered by the invasiveness vs. performance trade-off.
MITICS is developing a highly sensitive and biocompatible amplifying transducer platform for less invasive BCIs. We will leverage the Organic Electrochemical Transistor (OECT), a transducer that was recently shown to yield superior recordings of brain activity than electrodes, and dramatically improve its performance through the design of bespoke materials and coupling with high-gain, low-power amplifiers to achieve a paradigm shift in the invasiveness of BCIs. These highly sensitive amplifying transducers will be fabricated using printing processes which should allow custom designs and a strong decrease in fabrication costs. This breakthrough will allow BCIs to increase decoding accuracy and adoption, thus getting this
All-atom modeling work has also been performed to understand the ion uptake in the ON and OFF states of p- and n-type semiconductors. We have a developed a computational framework to model: (i) the changes in the structural organization of semiconducting polymer thin films in presence of an electrolyte solution and upon oxidation/reduction of the polymer chains; (ii) the evolution of the electrical conductivity with increasing electrochemical doping.
we have continued to develop and used sophisticated spectroscopic tools to investigate the electrochemical reactions in OECTs. Those include time-resolved spectro-electrochemistry, electrochemical terahertz conductivity, electrochemical Raman and interfacial Sum-Frequency-Generation (SFG) measurements, etc. The morphology of porous organic mixed conductor films was imaged. The electrochemical properties of new conjugated oligomer mixed conductors were studied. Temporal and spatial analysis of mixed conductivity in blend based OECTs were carried out. We have elucidated how backbone structure, side chain polarity, morphology, material blending, porosity and chain alignment affect the electrical and ionic processes in the devices.
Both p-type and n-type OECTs were developed and utilized to create complementary amplifiers with high gain and low power consumption. These devices were integrated into novel circuities and unitized for event-bases sensing.
In parallel, the consortium has worked with the development of all-printed OECTs operating in accumulation mode, to eventually simplify the design and manufacturing of complementary logic circuits. So far, successful results have been obtained for a p-type semiconducting polymer developed in the project. Similar development work to obtain all-printed n-type OECTs operating in accumulation mode is now in progress. Investigations on how different printing conditions affect the OECT switching performances have also been performed.
Next, a freely behaving rat model for validating cortical and implantable electrophysiology devices in the central and peripheral nervous system have been developed. It is used to validate both electrodes and transistors, in both recording and stimulation applications. Flexible circuits were tested, outperforming devices with external electronics. A platform has been developed separating ionic and electronic transport phenomena in doped and intrinsic organic semiconductors and the first example of hole-limited electrochemical doping was demonstrated.
Finally, the testbed development phase to validate MITICS technology for scalp EEG recordings is now completed. This includes the hardware integration of the developed amplification layer as well as the processing pipeline to compare with state-of-the-art systems.
A participation in the EIC T2M Venture Building Programme allows MITICS to explore the possibility of exploiting the OECT manufacturing platform.