A label-free electrochemical bianalyte immunosensor has been designed for simultaneous detection of lung cancer biomarkers (anti-MAGE A2 and anti-MAGE A11) using carbon nanotubes-chitosan (CNT-CHI) composite. To achieve this, acid-functionalized single-walled CNTs were used to prepare CNT-CHI gel and electrodes were fabricated by drop casting method onto graphite surface. Lung cancer biomarkers specific antigens (Ag), i.e., MAGE A2 and MAGE A11, were covalently immobilized onto CNT-CHI/graphite electrode separately for fabrication process. Fabricated immunoelectrodes (MAGE A2/CNT-CHI/graphite and MAGE A11/CNT-CHI/graphite) were characterized at each modification step by cyclic voltammetry (CV), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Both immunoelectrodes showed successful detection of respective analytes (anti-MAGE A2 and anti-MAGE A11) from 5 fg mL(-1) to 50 ng mL(-1) using differential pulse voltammetry (DPV). Both Ag/CNT-CHI/graphite immunoelectrodes (using MAGE A2 and MAGE A11) were independently capable of distinguishing specific and nonspecific analytes like CD59, D-dimers, etc. Response studies of both immunoelectrodes revealed successful demonstration of simultaneous detection of anti-MAGE A2 and A11 independently in a single experimental run when exposed to a mixture of various analyte concentrations in different combinations irrespective of the presence of other analyte present in the same vessel.
