Electrochemical Biosensing Platforms Using Phthalocyanine-Functionalized Carbon Nanotube Electrode

Iron-phthalocyanines (FePc) are functionalized at multi-walled carbon nanotubes (MWNTs) to remarkably improve the sensitivity toward hydrogen peroxide. We constructed a highly sensitive and selective glucose sensor on FePc-MWNTs electrode based on the immobilization of glucose oxidase (GOD) on poly-o-aminophenol (POAP)-electropolymerized electrode surface. SEM images indicate that GOD enzymes trapped in POAP film tend to deposit primarily on the curved tips and evenly disperse along the sidewalls. The resulting GOD^@POAP/FePc-MWNTs biosensor exhibits excellent performance for glucose with a rapid response (less than 8 s), a wide linear range (up to 4.0×10⁻³ M), low detection limits (2.0×10⁻⁷ M with a signal-to-noise of 3), a highly reproducible response (RSD of 2.6%), and long-term stability (120 days). Such characteristics may be attributed to the catalytic activity of FePc and carbon nanotube, permselectivity of POAP film, as well as the large surface area of carbon nanotube materials.