Investigation of poly(CTAB-MWCNTs) composite based electrochemical DNA biosensor and interaction study with anticancer drug Irinotecan

Development of sensitive, rapid and low-cost DNA detection tools and elucidation of the structural changes of DNA after interaction with chemotherapeutic drugs is of great significance. In this respect, the objective of this work was to construct a DNA biosensor based on electrodeposited cetyl trimethylammonium bromide-multiwalled carbon nanotubes (poly(CTAB-MWCNTs)) composite on single-use graphite electrodes (PGEs) for the direct detection of dsDNA and further implementation for the anticancer drug screening. The morphology and electrochemical characterization of the fabricated biosensor were utilized. The new surfactant-carbon nanotubes based electrode with porous composite structure led to significant improvement for the detection of dsDNA in the linear range of 4–150 μg mL −1 with detection limit of (LOD) 3.06 μg mL −1. Under the optimized conditions, the dsDNA modified poly(CTAB-MWCNTs)/PGEs were utilized to evaluate the binding interaction of an anticancer drug, irinotecan (CPT-11) with DNA by differential pulse voltammetry (DPV) and also by UV–vis spectroscopy. The guanine oxidation signal was linear in a CPT-11 concentration range of 2–500 μg mL −1 with LOD of 1.03 μg mL −1. Moreover, equilibrium constant (K) for the binding process was determined as 6.84 × 10 4 M −1. The applicability of the procedure was examined by quantitative measuring of CPT-11 in serum samples with high recoveries (106.0–98.2%). The proposed DNA biosensor hold considerable promise for different biointeraction applications.