Electrochemical Immunosensor with Enhanced Electrocatalytic Activity Using Au-Pt Alloy and f-MWCNT

Thin films of f-MWCNT (functionalised multiwalled carbon nanotubes) were formed on surface of Indium-Tin-Oxide (ITO) electrode of size ۱x۲ cm۲ by pouring ۱۰ µl of prepared solution of f-MWCNT (۱mg/ml). After drying the electrode, optimised gold-platinum alloy nanoparticles (Au۳Pt۱NP) were electrochemically deposited on the surface of modified ITO electrode under the optimised deposition conditions for solution and number of deposition cycles [۱–۵]. Deposition of layers of f-MWCNT and Au۳Pt۱NP (alloy nanoparticles of gold and platinum in ۳:۱ ratio) on ITO surface were confirmed by Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Analysis (EDAX) and X-ray diffraction (XRD) techniques while to investigate the electrochemical properties, electrochemical methods (cyclic voltammetry (CV), differential pulse voltammetry (DPV) and Electrochemical Impedance Spectroscopy (EIS) were used which indicated improved electrochemical performance of f-MWCNT/ITO electrode. This electrode was further modified with Serum Amyloid A protein (SAA) specific antibodies immobilisation (SAA-Ab/f-MWCNT/ITO) and used to detect protein biomarker Serum Amyloid A (APO-SAA). Electrochemical sensing studies by prepared immunoelectrode confirmed detection in a linearity range of ۱۰ fg/ml to ۱۰۸ fg/ml. By using equation ۳σ/sensitivity, Limit of detection (LOD) was found to be ۸.۷۸ fg/ml. Excellent selectivity of fabricated immunoelectrode for SAA biomarker, its stability up to five weeks with ۸۹.۱۸% of current retention and reproducibility studies with relative standard deviation of ۳.۹۵% indicates the successful fabrication of immunosensor that can be used to detect SAA biomarker.

کلیدواژه ها:

Multiwalled carbon nanotubes ، Gold-Platinum alloy nanoparticles ، Biomarker ، Immunoelectrode ، Electrochemical techniques