Innovative Molecularly Imprinted Electrochemical Sensor for Selective Nanomolar Detection of the Anti-COVID-19 Medication Molnupiravir

Abstract

For the first time, a green ecofriendly approach is applied, to develop a molecularly imprinted polymer (MIP) electrochemical for the assay of the oral anti-viral molnupiravir (MLN) in various matrices as confirmed by referring to analytical eco-scale, green analytical procedure index (GAPI), Raynie and Driver, analytical greenness metric (AGREE), and national environmental index (NEMI). AuNPs were chronoamperometry deposited on the glassy carbon electrode surface (GCE) using 0.01 gm ml−1 gold solution (HAuCl4.3H2O) in 0.5 M H2SO4 at a constant potential of −0.4 V for 60 s. Then, the MIP was created by electropolymerizing OPDA on the surface of AuNPs GCE using cyclic voltammetry in the potential range between −0.5 and +1 V for 15 cycles (scan rate: 50 mV.s−1). To optimize the sensor’s performance, factors such as number of electropolymerization cycles, template: monomer ratio, binding and rebinding time, pH of rebinding buffer, extraction solvent, deposition time of Au nanoparticles, order of deposition on the electrode; surface, as well as differential pulse voltammetry parameters including accumulation potential and time, and potential step, were all investigated. The detection limit was set at 0.00098 ng ml−1 (3 × 10−12M) and the linearity range of MLN was between 0.033 ng ml−1 and 164 ng ml−1 (1 × 10−10–5 × 10−7 M). The MIP sensor was employed for MLN determination in its pharmaceutical product (capsules), spiked human plasma, and human urine samples with mean recovery % ± mean relative standard deviation (RSD) (99.82% ± 0.53), (99.88% ± 0.62), and (97.90% ± 0.70), respectively. The investigated sensor provided good reproducibility, repeatability, and durability. Acceptable selectivity regarding MLN when mixed with structurally comparable compounds was proved with mean recovery % ± mean RSD (97.10% ± 0.03). Additionally, when molnupiravir was exposed to oxidative, hydrolytic, and thermal stress conditions, good results in stability-indicating studies served as an indicator of sensor selectivity. The developed electrode is coupled with a portable potentiostat, making it a promising point-of-care diagnostic platform for on-site measurements.