Engineering Proteins for PEDOT Dispersions: A New Horizon for Highly Mixed Ionic‐Electronic Biocompatible Conducting Materials

Abstract

Poly (3,4‐ethylenedioxythiophene) (PEDOT) doped with polystyrene sulfonate (PSS) is the most used conducting polymer from energy to biomedical applications. Despite its exceptional properties, there is a need for developing new materials that can improve some of its inherent limitations, e.g., biocompatibility. In this context, doping PEDOT is propose with a robust recombinant protein with tunable properties, the consensus tetratricopeptide repeated protein (CTPR). The doping consists of an oxidative polymerization, where the PEDOT chains are stabilized by the negative charges of the CTPR protein. CTPR proteins are evaluated with three different lengths (3, 10, and 20 identical CTPR units) and optimized varied synthetic conditions. These findings revealed higher doping rate and oxidized state of the PEDOT chains when doped with the smallest scaffold (CTPR3). These PEDOT:CTPR hybrids possess ionic and electronic conductivity. Notably, PEDOT:CTPR3 displayed an electronic conductivity of 0.016 S cm−1, higher than any other reported protein‐doped PEDOT. This result places PEDOT:CTPR3 at the level of PEDOT‐biopolymer hybrids, and brings it closer in performance to PEDOT:PSS gold standard. Furthermore, PEDOT:CTPR3 dispersion is successfully optimized for inkjet printing, preserving its electroactivity properties after printing. This approach opens the door to the use of these novel hybrids for bioelectronics.

Copolymers of Gelatin-graft-poly(3-hexylthiophene) for Transient Electronics

“…The circular dichroism (CD) spectrum of gelatin in Gel- g -P3HT-2 (Figure S7), compared to that of pristine gelatin, shows a decrease in the amplitude of the negative band at 198 nm and a perturbation of the very weak positive band at 220 nm, associated with polyproline II helix conformation (Figure S7). The CD results confirm that the gelatin structure remains largely unchanged after the attachment of P3HT to the gelatin backbone, which is consistent with the previous report …”

“…The CD results confirm that the gelatin structure remains largely unchanged after the attachment of P3HT to the gelatin backbone, which is consistent with the previous report. 16 The thermal properties of the graft copolymers were investigated by DSC and TGA. DSC trace of Gel-g-P3HT-2 (Figure 2C) suggests that Gel-g-P3HT-2 showed two glass transition temperatures (T g1 at −19.13 °C and T g2 at 91.40 °C).…”

“…11 Proteins, as a class of biodegradable polymers, have also been integrated with CPs to prepare composites for transient polymer electronics, serving to introduce degradability to the composite system [12][13][14][15]20 and/or act as the dopant for CPs. 16 For instance, PEDOT:PSS was mixed with curli fibers (a protein polymer) to obtain a composite thin film, exhibiting self-healing ability and enhanced conductivity compared to those of the pristine PEDOT:PSS. 20 Although crystalline regions are necessary to facilitate efficient electron charge transfer in CPs, 22 it has been also recognized that charge transport can be enhanced via connecting ordered regions (crystallites and aggregates) by long conducting polymer chains.…”

“…As a result, functionalized CP-based materials with enough conductivity and degradability are emerging as the ideal materials to fulfill the requirements of transient electronics. , The typical approaches to fabricate transient polymer electronics are to prepare either composites or block copolymers of conductive polymers and degradable polymers, with applications ranging from biomedical applications to organic thin-film transistors. − For example, Gandla et al reported the composites of conducting polymer poly­(3,4-ethylenedioxythiophene)-poly­(styrenesulfonate) (PEDOT:PSS) and degradable polymer polylactic acid (PLA) that were utilized to fabricate transient electrophysiological sensors for monitoring of the signals generated during eye movement and control home electronics in real-time, achieving human–machine interactions . Proteins, as a class of biodegradable polymers, have also been integrated with CPs to prepare composites for transient polymer electronics, serving to introduce degradability to the composite system − , and/or act as the dopant for CPs . For instance, PEDOT:PSS was mixed with curli fibers (a protein polymer) to obtain a composite thin film, exhibiting self-healing ability and enhanced conductivity compared to those of the pristine PEDOT:PSS .…”