Dopant-Dependent Electrical and Biological Functionality of PEDOT in Bioelectronics

Abstract

The aspiration to interact living cells with electronics challenges researchers to develop materials working at the interface of these two distinct environments. A successful interfacing coating should exhibit both biocompatibility and desired functionality of a bio-integrated device. Taking into account biodiversity, the tissue interface should be fine-tuned to the specific requirements of the bioelectronic systems. In this study, we pointed to electrochemical doping of conducting polymers as a strategy enabling the efficient manufacturing of interfacing platforms, in which features could be easily adjusted. Consequently, we fabricated conducting films based on a poly(3,4-ethylenedioxythiophene) (PEDOT) matrix, with properties modulated through doping with selected ions: PSS− (poly(styrene sulfonate)), ClO4− (perchlorate), and PF6− (hexafluorophosphate). Striving to extend the knowledge on the relationships governing the dopant effect on PEDOT films, the samples were characterized in terms of their chemical, morphological, and electrochemical properties. To investigate the impact of the materials on attachment and growth of cells, rat neuroblastoma B35 cells were cultured on their surface and analyzed using scanning electron microscopy and biological assays. Eventually, it was shown that through the choice of a dopant and doping conditions, PEDOT-based materials can be efficiently tuned with diversified physicochemical properties. Therefore, our results proved electrochemical doping of PEDOT as a valuable strategy facilitating the development of promising tissue interfacing materials with characteristics tailored as required.

Strategies for interface issues and challenges of neural electrodes

“…20,37,43,44 When the glial scar becomes too bushy and the neurons around the electrode die due to inflammation (acute and chronic), 45,46 the electrode loses its function. So far, methods for perfecting the compatibility of bioelectrodes include: (i) surface coating; 47 (ii) doping; 48 (iii) covalent grafting; 49 and (iv) layer-by-layer self-assembly technology based on electrostatic attraction. 50…”

Guidelines for a Morphometric Analysis of Prokaryotic and Eukaryotic Cells by Scanning Electron Microscopy

“…In our research, we used SEM imaging to visualise the morphology of two types of biological samples representing prokaryotic and eukaryotic cells: a model Gram-negative bacterial strain Escherichia coli (DSM 30083, U5/41), and a cultured cell model of central nervous system neurons, namely rat neuroblastoma cell line B-35 (ATCC ® CRL-2754™). The details of culturing both types of cells can be found in our previous reports [ 43 , 44 , 45 ]. According to the optimised sample preparation protocol [ 43 , 44 , 45 ], cells were fixed using 3% glutaraldehyde for 24 h, then washed three times with sterile distilled water.…”

“…The details of culturing both types of cells can be found in our previous reports [ 43 , 44 , 45 ]. According to the optimised sample preparation protocol [ 43 , 44 , 45 ], cells were fixed using 3% glutaraldehyde for 24 h, then washed three times with sterile distilled water. Subsequently, samples were dehydrated by immersing them for 10 min in the solutions of ethanol with increasing concentrations (30%, 50%, 70%, 80%, 90%, 95%, 99.8%), then dried for 24 h at 50 °C.…”

“…SEM is widely used in microbiological analysis to assess the morphology of bacterial cells, their adhesion to the surface, as well as their tendency to form bacterial biofilms [ 43 , 44 , 45 ]. Moreover, SEM allows to estimate the number and distribution of microorganisms on the investigated surface [ 43 ].…”

“…Moreover, SEM allows to estimate the number and distribution of microorganisms on the investigated surface [ 43 ]. The versatility of results that can be collected by SEM analysis makes this type of microscopy favourable for the evaluation of antimicrobial character of medical surfaces [ 43 ], effectiveness of new antibiotic agents [ 47 ] or bioactive materials [ 44 , 45 ]. What is more, a high resolving power of SEM allows obtaining reliable information on the state of microorganisms in their natural environment [ 47 , 48 , 49 ].…”