Metallophthalocyanine-nanofibre-based electrodes for electrochemical sensing of biomolecules

Abstract

Metal phthalocyanines, possessing rich redox chemistry due to the presence of the central metal cation and pyrrolic nitrogen atoms of the macrocycle, are explored as electrochemical sensors. Nickel phthalocyanine nanofibres (NiPc NF) prepared by a simple chemical route are coated on a pencil graphite rod and the electrocatalytic performance of NiPc NF electrode is investigated for quantitative detection of ascorbic acid (AA) in 0.2 M phosphate buffer solution. The performance of NiPc NFs is shown to be superior to that of commercial NiPc and is attributed to the high electrochemically active surface area available for fibres. The electrode exhibits linearity for the detection over a wide concentration range of AA from 5.5 μM to 5.2 mM. The detection limit for AA sensing with NiPc-NF-modified electrode is 1.5 μM. The higher performance of NiPc fibres due to its nanostructure morphology may be utilized for the quantitative detection of other biomolecules.

Solution Processable Transition Metal Phthalocyanine Nanofibres

“…It can be noticed that the aspect ratio is very high in the case of FePc, CoPc and CuPc. In the case of NiPc, the morphology showed a width of 150 nm and length of 5 μm, shorter than FePc, CoPc and CuPc. ZnPc also exhibits structural features similar to the case of MnPc, with a width of about 650 nm and length of 25–35 μm.…”

“…Also, the exchange current density values derived from the Tafel plots are found to be 7.49 × 10 −3 and 2.51 × 10 −3 mA cm −2 for CuPc NF and CoPc NF, respectively. The high electrochemical activity of the nanofibres is attributed to the higher electrochemical active surface area available for redox reactions of the analyte compared to the commercially procured ones as reported earlier …”

“…In this report, we extend the simple chemical synthesis, which was reported earlier by us for NiPc synthesis, as a general route to the synthesis of various other transition metal MPcs (M=Mn, Fe, Co, Cu and Zn). The MPc molecules self‐assemble and stack into one‐dimensional (1‐D) nanostructures.…”

“…It is a widely investigated system for electrochemical applications such as energy storage and electrochemical sensing. The richness in electrochemical activity arises from the metal centre and the nitrogen atoms constituting the macrocycle that are capable of undergoing redox or Faradaic reactions …”

“…This bottom‐up approach can be applied to other MPcs, in general, without using surfactants providing high aspect ratio nanostructures. We have earlier shown the solution processing of NiPc nanofibres as modified electrodes for supercapacitor and electrochemical sensing applications . Lately, MPc modified electrodes have also received attention for electrochemical oxygen reduction facilitated through M 2+ redox reactions.…”