Innovative approaches in electrochemical sensing for the sensitive and selective label-free detection of vericiguat in real blood samples

An innovative imprinted electrochemical platform was designed for the first time to detect vericiguat (VER), a soluble guanylate cyclase stimulator, in real samples. The smart sensor was fabricated by mixing a molecularly imprinted polymer (MIP) with graphite powder, obtained from a broken battery, and multiwalled carbon nanotubes (MWCNT) in the presence of paraffin oil. Density functional theory (DFT) was utilized not only to predict promising monomers for the polymerization process but also to investigate the interaction between the selected monomers and the VER template. Highly interactive acrylamide and methyl methacrylate monomers were first employed to interact with the VER template; then, the initiator, 2,2′-azobisisobutyronitrile, and the cross linker, ethylene glycol dimethacrylate, were added. The resulting MIP was characterized using different techniques including Fourier transform infrared spectroscopy, atomic force microscopy, scanning electron microscopy, and elemental mapping. The electrochemical performance of the synthesized sensor was investigated using cyclic voltammetry and electrochemical impedance spectroscopy. Using differential pulse voltammetry, the fabricated imprinted sensor was successfully utilized to monitor VER with a low limit of detection of 1.68 × 10 −9 mol L −1 over a linear concentration range of 5.1 × 10 −9 mol L −1 –2.3 × 10 −4 mol L −1 , with a correlation coefficient of 0.98. In addition, it showed excellent selectivity in the presence of other coexisting molecules, high stability (32 days), and good reproducibility (RSD = 4.68 %) and repeatability (RSD = 3.86 %). The proposed technique was successfully employed to detect VER in real blood samples and pharmaceutical tablets with quantitative extraction recovery (99.40 %–100.05 %).