Edge and Basal Plane Anisotropy of a Preanodized Pencil Graphite Electrode Surface Revealed Using Scanning Electrochemical Microscopy and Electrocatalytic Dopamine Oxidation as a Molecular Probe

Electrical Wiring of Malarial Parasite Intermediate Hematin on a Tailored N-Doped Carbon Nanomaterial Surface and Its Bioelectrocatalytic Hydrogen Peroxide Reduction and Sensing

“…It is interesting to note that the N-GQD-loaded modified electrode exhibited a well-defined redox peak at an apparent standard electrode potential (E o ’) of −0.410 V vs Ag/AgCl, with a surface excess value (Γ Hemat ) of 3.54 × 10 –9 mol cm –2 (major peak) and peak-to-peak separation value (Δ E p ) of 75 mV. There was a minor peak at 0 V vs Ag/AgCl, which may be due to the immobilization of hematin on energetically different edge/basal sites of MWCNT . Twenty successive CV responses of the modified electrode at a scan rate 50 mV s –1 yielded the i pa -relative standard deviation value, 2.9%, demonstrating the excellent stability of the modified electrode.…”

“…A well-defined electroreduction response at E pc = −0.423 V vs Ag/AgCl, along with a minor reduction peak at 0 V vs Ag/AgCl (C1’), was observed for the H 2 O 2 reduction reaction on the modified electrode. The minor peak observed at low potential is attributed to hematin immobilized on energetically distinct sites of MWCNT, such as the edge plane site, while the major peak observed is associated with the larger basal plane sites of the MWCNT . When the same experiment was performed with an unmodified GCE/MWCNT@N-GQD, a 40-fold decrease in the cathodic peak current signal and a reduction in potential ranging from 200 to 600 mV were noticed.…”

“…These controlled experiments establish biomimicking conditions for the electrochemical and ET activity of the hematin in physiological condition. Unlike the electron microscopic images, which provide a bulk morphology of the surface, SECM offers real-time applications for visualizing electroactive spots on the surface . By correlating the electron microscopic image with SECM data, one can obtain information about the real-time ET behavior of the biomimicking system.…”

Benzene layer-aligned electrochemical transformation of SWCNTs to redox-active macro-walled CNTs: enabling oxygen interference-free monitoring of ROS release from HeLa cancer cells

“…To visualize the active catalytic site, the H 2 O 2 reduction reaction was also used as a molecular probe in the redoxcompetitive (RC) mode of the SECM operation, wherein the same electrochemical reactions are performed for imaging on both the substrate and the tip. Previously, our group implemented the RC mode of SECM imaging approach for visualizing the activities of a pre-anodized pencil graphite electrode (PGE) using DA, 78 nickel hexacyanoferrate, 79 and carbon nanofiber modified Binol redox species. 80 Fig.…”

Nanosheet like Ni-MOFs/MWCNTs Composite Synthesis: Application to Trace Level Dopamine Measurement

“…Upto now, many articles for dopamine sensing were reported at pH 7 to 7.4. [42][43][44] In this study, the reaction mechanism is significantly influenced under mildly acidic conditions, such as in pH 6 acetate buffer. At this pH level, dopamine exists primarily in its protonated form, and the deprotonation of its phenolic hydroxyl group, a critical precursor for subsequent reactions like the Michael addition, is limited.…”