# The Morphological Dependence of PEDOT on the Supporting Electrolytes Used and the Acquisition of Gold Nanoparticles with a View to Their Use in the Covalent Modification of the Ki-67 Antibody

## TL;DR

This study explores how different electrolytes affect the structure of PEDOT films and gold nanoparticles, aiming to improve antibody modification for biosensors.

## Contribution

The study identifies TBAPF6 as the optimal electrolyte for creating PEDOT films and gold nanoparticles suitable for covalent antibody modification.

## Key findings

- Supporting electrolytes significantly influence the morphology and conductivity of PEDOT films.
- Gold nanoparticles can be electrosynthesized on all films, with TBAPF6 showing the best distribution for antibody modification.
- SEM and ESEM-EDS confirmed the structural and compositional differences in the films and nanoparticles.

## Abstract

We studied the influence of different supporting electrolytes (TBAPF6, TMAPF6, TEAPF6, TBAClO4, and LiClO4) on the morphology of PEDOT films electrochemically polymerized on screen-printed carbon electrodes, as part of which the synthesis of gold nanoparticles was tested for the subsequent modification of Ki-67 antibodies. Electrochemical deposition of the polymer was carried out using cyclic voltammetry and was characterized in the same way in solutions without the monomer. The nanoparticles were obtained using chronoamperometry at a constant potential for 3 s. The processes of p- and n-doping/undoping of both deposits (with and without gold) were studied, as was their characterization using SEM and ESEM-EDS. It was found that the supporting electrolytes intervened in the morphology and conductivity of the polymer films. In all films, it was possible to electrosynthesize gold nanoparticles, but the type of supporting electrolyte also influenced their distribution, showing that for this study, the most suitable were those obtained using TBAPF6, giving the most promising results for the covalent modification of antibodies to obtain future biosensors.