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. 2023 Mar 24;28(7):2917.
doi: 10.3390/molecules28072917.

Self-Assembly and Electrical Conductivity of a New [1]benzothieno[3,2-b][1]-benzothiophene (BTBT)-Peptide Hydrogel

Anna Fortunato  1 , Rafael Cintra Hensel  1 , Stefano Casalini  1 , Miriam Mba  1
Affiliations

Self-Assembly and Electrical Conductivity of a New [1]benzothieno[3,2-b][1]-benzothiophene (BTBT)-Peptide Hydrogel

Anna Fortunato et al. Molecules. .

Abstract

The conjugation of small-molecule semiconductors with self-assembling peptides is a powerful tool for the fabrication of supramolecular soft materials for organic electronics and bioelectronics. Herein, we introduced the benchmark organic semiconductor [1]benzothieno[3,2-b][1]-benzothiophene (BTBT) within the structure of a self-assembling amphipathic peptide. The molecular structure of the conjugate was rationally designed to favour π-π stacking between BTBT cores and π-delocalization within the self-assembled architectures. Hydrogels with fibrillar structure were obtained upon self-assembly. Spectroscopic studies confirmed that both hydrogen bonding between peptide segments and π-π stacking between BTBT chromophores are responsible for the formation of the 3D fibrillar network observed by transmission electron microscopy. The hydrogel was successfully deposited on gold interdigitated electrodes and a conductivity up to 1.6 (±0.1) × 10-5 S cm-1 was measured.

Keywords: [1]benzothieno[3,2-b][1]-benzothiophene; electrically conductive hydrogel; peptide; peptide-chromophore conjugate; supramolecular hydrogel; π-gel.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Scheme 1
Scheme 1
Synthesis of the BTBT-peptide conjugate 1.
Figure 1
Figure 1
(a) Photograph of the gel under daylight and UV lamp; gel formation was assessed by the vial inversion test. (b,c) TEM micrographs of the xerogels.
Figure 2
Figure 2
(a) Frequency sweep experiment and (b) strain sweep experiment of gel at 0.5 wt % concentration; filled circles represent G′ while open circles represent G″.
Figure 3
Figure 3
Normalized (a) UV-Vis absorption and (b) emission spectra and (c) CD spectra of 1 in aqueous solution at 10−5 M (black line), at 5.6×10−3 M (red line) and the gelled sample (blue line).
Figure 4
Figure 4
Schematic representation of the deposition process.
Figure 5
Figure 5
Dark-field optical microscope images of 1 deposited on gold interdigitated electrodes (a,b). (c,d) Dark- field optical microscope images before and after rising with water, respectively. White circle highlights the removal of adsorbed dendrimeric shapes.
Figure 6
Figure 6
I-V plots of the BTBT onto Au IDEs in which the applied voltage swept from (a) 0 V to +1 V, and (b) −3 V to +3 V.
See this image and copyright information in PMC

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