Organic materials have significant potential for bio-functional neural interfacing given that their "soft" nature offers better mechanical compatibility with the nerve tissues than conventional semiconductors, and their flexibility allows realization of the non-planar forms typically required for biomedical implants. The integration of living cells into organic semiconductors is an important step towards the development of bio-organic electronic transducers of cellular activity from neurons. Moreover, an improved capacitive coupling between organic-functionalized interface and neurons is demonstrated in sensing devices, leading to a large transconductance and high device sensitivity at low voltages. In this respect, we recently demonstrated an organic transistor structure (O-CST) based on the ditridecylperylene-3,4,9,10-tetracarboxylic diimide (P13) n-type organic semiconductor provides bidirectional stimulation and recording of dorsal root ganglion primary neurons with a signal-to-noise ratio exceeding that of standard microelectrode array systems [1]. It is self-evident that a clear understanding at the micorscopic level of the functional and structural properties of device active-layer interfacing with the cell culture environment is crucial for the development of a device platform suitable for stimulation and recording of neural cells in vitro and for the therapeutic electrical stimulation in vivo. Here, we report on a detailed physical-chemical characterization of n-type perylene-derivative implemented as active layer in the O-CST device in order to demonstrate its suitability as interface platform for organic neuroelectronic devices [2]. Notably, the morphological, structural and photophysical features of P13 thin-films do not change significantly upon exposure to the cell-culture media. It is noteworthy that the field-effect transistors preserve their electrical characteristics even after 10 days of incubation in cell culture media. Finally, we report on a impedance spectroscopy study performed onto O-CST device platform aimed at optimizing the device sensing performance by means of device architecture engineering (i.e. layer thickness, materials implemented electrode geometry). Indeed, it is generally known that the ability to record action potentials from individual neurons is dependent on a trade-off between the geometric area of the recording site and the site impedance, often referred to as the trade-off between selectivity and sensitivity. Thus, the cross-correlation of different electrical, spectroscopic, and morphological investigation techniques coupled to cell-viability and electrophysiology tools allows us to validate n-type perylene derivatives as a suitable long-term interface platform for organic neuroelectronic devices. [1] Benfenati V., et al. Nature Mat., 2013, 12, 672-680. [2] Toffanin S., et al. J. Mater. Chem. B, 2013, 1, 3850-3859.
Ruling Functionality and Structure of Perylene-Based Device Platform for the Stimulation and Recording of Neuron Bioelectrical Activity
Giampiero Ruani;
2014
Abstract
Organic materials have significant potential for bio-functional neural interfacing given that their "soft" nature offers better mechanical compatibility with the nerve tissues than conventional semiconductors, and their flexibility allows realization of the non-planar forms typically required for biomedical implants. The integration of living cells into organic semiconductors is an important step towards the development of bio-organic electronic transducers of cellular activity from neurons. Moreover, an improved capacitive coupling between organic-functionalized interface and neurons is demonstrated in sensing devices, leading to a large transconductance and high device sensitivity at low voltages. In this respect, we recently demonstrated an organic transistor structure (O-CST) based on the ditridecylperylene-3,4,9,10-tetracarboxylic diimide (P13) n-type organic semiconductor provides bidirectional stimulation and recording of dorsal root ganglion primary neurons with a signal-to-noise ratio exceeding that of standard microelectrode array systems [1]. It is self-evident that a clear understanding at the micorscopic level of the functional and structural properties of device active-layer interfacing with the cell culture environment is crucial for the development of a device platform suitable for stimulation and recording of neural cells in vitro and for the therapeutic electrical stimulation in vivo. Here, we report on a detailed physical-chemical characterization of n-type perylene-derivative implemented as active layer in the O-CST device in order to demonstrate its suitability as interface platform for organic neuroelectronic devices [2]. Notably, the morphological, structural and photophysical features of P13 thin-films do not change significantly upon exposure to the cell-culture media. It is noteworthy that the field-effect transistors preserve their electrical characteristics even after 10 days of incubation in cell culture media. Finally, we report on a impedance spectroscopy study performed onto O-CST device platform aimed at optimizing the device sensing performance by means of device architecture engineering (i.e. layer thickness, materials implemented electrode geometry). Indeed, it is generally known that the ability to record action potentials from individual neurons is dependent on a trade-off between the geometric area of the recording site and the site impedance, often referred to as the trade-off between selectivity and sensitivity. Thus, the cross-correlation of different electrical, spectroscopic, and morphological investigation techniques coupled to cell-viability and electrophysiology tools allows us to validate n-type perylene derivatives as a suitable long-term interface platform for organic neuroelectronic devices. [1] Benfenati V., et al. Nature Mat., 2013, 12, 672-680. [2] Toffanin S., et al. J. Mater. Chem. B, 2013, 1, 3850-3859.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
