A robust electrochemical sensing platform for the detection of erlotinib based on nitrogen-doped graphene quantum dots/copper nanoparticles-polyaniline-graphene oxide nanohybrid

Erlotinib is a potent and highly specific tyrosine kinase inhibitor with the hindering effects on the growth of cancer cells. An electrochemical sensor with the great sensitivity and selectivity was fabricated for determining erlotinib by using a graphite rod electrode modified by the nitrogen-doped graphene quantum dots (N-GQDs) and a ternary nanohybrid comprising copper nanoparticles, polyaniline, along with graphene oxide (N-GQDs/CuNPs-PANI@GO) for the first time. The establishment of PANI and CuNPs was done simultaneously on the GO surface by the in situ oxidative polymerization method. The morphological characteristics and elemental structure of the synthesized nanoparticles were examined by some microscopy techniques and x-ray energy/diffraction methods. The fabricated sensor represented the electrocatalytic activity towards erlotinib with a linear detection range from 1.0 nM to 35.0 mu M, a detection limit of 0.712 nM, and a sensitivity of 1.3604 mu A mu M-1. Moreover, the N-GQDs/CuNPs-PANI@GO sensor showed acceptable stability up to 30 d (94.82%), reproducibility (RSD values of 3.19% intraday and 3.52% interday), and repeatability (RSD value of 3.65%) as a novel and powerful electrochemical sensor. It was successfully applied to monitor erlotinib in the drug-injected aqueous solution, serum, and urine samples that proved the capability of the sensor for the erlotinib monitoring in the biological samples.