E.A. Iusupovskaia1

1 Institute for Bionic Technologies and Engineering, Sechenov First Moscow State Medical University (Sechenov University) (Moscow, Russia)

1 yusupovskaya_e_a@staff.sechenov.ru

An organic semiconductor implant based on HpPc/PTCDI was previously developed as a capacitive photocapacitor for peripheral nerve stimulation and is activated by light with a wavelength of 625 nm. The initial polyimide substrate with a thickness of 25 microns caused tissue damage due to its high rigidity compared to nervous tissue.

The aim of the study is to improve the mechanical characteristics of the implant by replacing the substrate material to increase the flexibility of the implant. At the same time, it is important to maintain the efficiency of the device without reducing the level of photon voltage generated on it and the density of the photocurrent at constant parameters of the light pulses.

As a result of the study, a scientific justification was presented for the possibility of replacing a polyimide film with a thickness of 25 nm with a film made of parylene with a thickness of 5 microns. This replacement reduces bending stiffness by 125 times while maintaining photovoltaic characteristics: the photovoltaic voltage of optoelectronic devices on both types of substrates reaches about 330 mV, and the photocurrent density is 8.2 A/m2. Thus, parylene-C significantly improves the mechanical biocompatibility of the implant without compromising its functional characteristics.

The practical significance of the work is due to the fact that the substrate material proposed and described in the work will provide a reduction in injury reduction by the device during implantation due to the greater flexibility of the implant on a parylene substrate. The photovoltaic characteristics of the stimulation device remain at the same level.

Iusupovskaia E.A. Improving the mechanical properties of an organic semiconductor implant for optoelectronic neurostimulation // Biomedical Radioelectronics. 2026. V. 29. № 6. P. 136−140. DOI: https://doi.org/10.18127/j15604136-202606-23

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