Amino Acid Modified Glassy Carbon Electrode Surface Ion Channel Behavior

The modification of carbon surface is an important objective in electrochemistry and material science and much attention has been paid to it. In this work, three glassy carbon electrodes (GCEs) modified with glycine (Gly), aspartic acid (Asp) and lysine (Lys), respectively, were prepared via an electrochemical oxidation procedure. It was due to the pole defect in the amino acid modified electrode that Fe(CN)₆^3-/4- ion channel was formed. The ion channel behaviors of amino acid modified GCEs were investigated. The study has potential application in improving the blood compatibility of biomedical materials to modify the surface of carbon electrode through electrochemical oxidation. The experiment results are as follows:1. Three GCEs modified with glycine (Gly), aspartic acid (Asp) and lysine (Lys), respectively, had been fabricated via an electrochemical oxidation procedure. The modified layer was not compact which conduced to the formation of the ion channel. The best condition of forming ion channels were: scanning potential 0.5-2.0 V, scanning rate, 10 mV/s, and three cycles.2. The electrochemical behaviors of amino acid modified GCEs were investigated via Fe(CN))₆^3-/4- as an electroactive redox probe. The results proved that the formation of ion channels on the surface of amino acid modified GCEs. While the ion channel behaviors on different amino acid modified GCEs had difference.3. The ion channel behaviors of the amino acid modified GCEs were studied with Fe(CN)₆^3-/4- by varying the concentration of H⁺. Results showed that the ion channel behaviors of different amino acid modified GCEs had the same trend: at lower pH, ion channel was opened relatively, while at higher pH it was closed relatively.4. To further investigate the behaviors of ion channel of amino acid modified GCEs, Ca²⁺ were added to the Fe(CN)₆^3-/4- solution to change the charges on the surface of the modified electrodes. Results proved that at higher concentration of Ca²⁺, ion channel was opened relatively, whereas at lower concentration of Ca²⁺, it was closed relatively.5. The ion channel behaviors of three modified GCEs were investigated under the same conditions to show the similarities and the differences of the ion channels. It was found that the behaviors of ion channel were due to electrostatic interactions. The different structures of amino acids resulted in the different ion channel behaviors of the amino acid modified GCEs.