Combined Organic Wireless Stimulator for Optoelectronic Control of a Single Cell

A lofty vision in the bioelectronic field is photoelectrical addressability at the single-cell level realized by means of miniature light-driven stimulation devices capable to elicit a sufficient action potential, which remains unmet by the state-of-the-art technology. Here, we report an optical wireless cell stimulator based on the combination of stable biocompatible multilayered organic semiconductors and PEDOT:PSS, an electroactive polymer formulation exhibiting superior ionic charge accumulation commonly used for device interconnection. Unconventional sandwiching of PEDOT:PSS between the organic semiconductor layers resulted in a remarkable increase of the charge density 3-fold in comparison with the state-of-the-art single-junction devices. The performance of our several PEDOT:PSS-sandwiched devices was tested using single-cell electrophysiology measurements of Xenopus laevis oocytes and compared with a relevant numerical model. A photoinduced opening of the voltage-gated K+ channels occurring at the excitation light intensity level 10–100 times lower than that of the conventional single-junction devices was demonstrated. Our miniature light-driven stimulation device significantly outperforms the existing devices, paving the way for the generation of organic photovoltaic devices, such as wireless retinal implants with electrooptical response operated well below the maximum permissible exposure limit.