Ionic‐complementary peptide‐modified highly ordered pyrolytic graphite electrode for biosensor application

Abstract

Ionic-complementary peptides are promising new biomaterials with potential applications in bionanotechnology. In the present investigation, a typical ionic-complementary peptide, EFK16-II, was used to modify a highly ordered pyrolytic graphite (HOPG) electrode. Upon modification, peptide nanofibers, parallel or oriented 608 or 1208 to each other, were formed on the surface of HOPG electrode. Surface wettability of the electrode was improved as indicated by a significant decrease in the water contact angle. The electrochemical response of the EFK16-II nanofiber-modified HOPG electrode for the ferricyanide/ferrocyanide redox couple was characterized. Cyclic voltammograms indicated that the presence of peptide nanofibers on the HOPG electrode did not block electron transfer at slow scan rates ($2 mV/s), but did so at high scan rates ($ 100 mV/s). A model enzyme glucose oxidase (GOx) was covalently immobilized onto this nanofiber-modified electrode, and its potential as an enzyme-based biosensor for glucose was examined. At an applied potential of þ0.45 V (vs. Ag/AgCl), the current increased linearly with glucose concentration up to 7.5 mM and a relative high sensitivity was obtained at 11.3 AE 1.0 nA/(mM mm 2 ). The immobilized GOx showed high affinity for glucose, with a Michaelis-Menten constant K m of 6.8 AE 0.9 mM. It also exhibited relatively good storage and operational stabilities, and reflected in only a small decrease (13%) in the current response after 1 month storage and negligible changes upon 50 cyclic voltammetric scans.The results presented here demonstrate an excellent potential of the use of ionic-complementary peptides to modify electrode surfaces for biomolecular sensing and diagnostics.

Selective Detection of Target Proteins by Peptide‐Enabled Graphene Biosensor

“…This enables the solid binding peptides to assemble and function in aqueous solutions and in biological buffers . Various graphite, graphene‐, and CNT‐binding peptide sequences and poly amino acids have been identified in the literature through combinatorial display and other means. They have been employed for applications such as bioinorganic nano‐material formation, and non‐specific control of surface chemistry .…”

“…Various graphite, graphene‐, and CNT‐binding peptide sequences and poly amino acids have been identified in the literature through combinatorial display and other means. They have been employed for applications such as bioinorganic nano‐material formation, and non‐specific control of surface chemistry . The dodecapeptide GrBP5‐WT (with amino acid sequence: IMVTESSDYSSY, affinity constant: K a = 3.78 μM −1 ) is unique among graphite‐ and CNT‐binding peptide sequences identified so far as, upon binding, it forms long‐range ordered, uniform, and crystallographic molecular nanostructures on graphitic materials.…”

Controlling the Surface Chemistry of Graphite by Engineered Self-Assembled Peptides

“…They have been employed for applications such as bioinorganic nano-structure formation 35 as well as non-specific control of surface chemistry 29 .…”

Phenylalanine-Rich Peptide Mediated Binding with Graphene Oxide and Bioinspired Synthesis of Silver Nanoparticles for Electrochemical Sensing

“…Previously, a few sequence-designed peptides such as EPLQLKM, YWYAF, and GAMHLPWHMGTL with highly specific graphene-binding ability have been discovered through both experimental and theoretical studies [24][25][26][27]. In addition, the formed graphene-peptide nanohybrids have shown high potentials to fabricate graphene-NPs [23,28] and graphene-hydroxyapatite [22,29] nanohybrids for various biomedical applications.…”