Electrochemical Response alfa/beta-peptides: Influence of the Peptide Length, stereochemistry and Self-Assembly on the Performance of Peptide-Based Electrochemical Sensors

Electrochemical Response alfa/ß-peptides: Influence of the
Peptide Length, Stereochemistry and Self-Assembly on the Performance of Peptide-Based Electrochemical Sensors

The electrochemical response of alfa-beta-peptides with (L-Ala-ß-Fpg)n sequence, where ß-Fpg refers to syn acid, has been investigated examining the effects of the peptide length (n = 1—3), the stereochemistry of the ß2’3 diaryl-amino acid and their self-assembly. Alfa/ß-Peptides have been deposited by drop-casting on a conducting polymer (CP) film, which is previously electropolymerized on a stainless steel conducting substrate. The current-potential response of the CP coated by the different studied peptides suggests that, for am-peptides, the role played by the electron transport through intermolecular stacking of aromatic side groups prevails over peptide length and stereochemistry. In order to prove such a hypothesis, the experimental conditions used to achieve an ordered self-assembly are optimized for one ofthe am-peptides. The achieved self-assembled structures, which consist of well-defined long microfibers, considerably improve the electrochemical response of the CP. Finally, the prepared am-peptide-based electrodes are used to electrochemically detect the oxidation of nicotinamide adenine dinucleotide (NADH). The analytical parameters are better for electrodes with well-defined peptide microfibers than for uncoated CP, corroborating the importance of stacking interactions in the response of C/F-peptides.

DOI: 10.1002/admi.202500254