Bioinspired composite: influence on electrical conductivity of carbon nanotubes with different hydrodynamic radii in photoresist

Introduction

Based on carbon nanotubes, neuroimplants are being developed whose task is to faciliatate communication between neurons through a damaged area of tissue, as well as blocking pain signals. In such systems, feedback between the stimulated area and the neurostimulator is important. The design of such implants is being developed, taking into account the characteristics of the biological system.

The bioinspired composite includes single-walled carbon nanotubes (SWCNTs), bovine serum albumin (BSA), collagen, chitosan, and Eosin Y. To achieve the required electrical conductivity with minimal use of nanotubes, a study was conducted to determine the effect of the size of their bundles.

Methods

When developing artificial synapses, the use of SWCNTs in combination with biopolymers is promising. The change in electrical conductivity of the composite manufactured by photolithography, with a content of 0.03 wt. % SWCNTs in the photoresist, was estimated. As a result of ultrasonic treatment, variants of SWCNT size distributions in bundles were obtained, which were characterized by the dynamic light scattering (DLS) method.

Results

Depending on the amounts of bundles of SWCNTs with different hydrodynamic radii, the values of relative specific conductivity of the composite were obtained. The specific indicators were 1 (0.35 μm, 73%), 1.7 (28 μm, 99%) and 3.7 (95 μm, 97%). Conductivity was normalized relatively to the minimum obtained value.

Conclusions

With an increase in the size of bundles of nanotubes in a composite manufactured by photolithography, an increase in specific conductivity by 3.7 times is achieved. The structure of such a neurointerface is based on the principles of the original biological system, which contributes to its bio-inspired design and functionality.

Funding: This work was carried out with the financial support of the Ministry of Education and Science of Russia within the framework of a major scientific project (Agreement № 075-15-2024-555 from 25.04.2024).